A new book from Dr. Ricky Lee entitled "Law and Regulation of Commercial Mining of Minerals in Outer Space (Space Regulations Library)" from Springer Press (Due: February 10, 2012). From Springer Press...
This monograph addresses the legal and policy issues relating to the commercial exploitation of natural resources in outer space. It begins by establishing the economic necessity and technical feasibility of space mining today, an estimate of the financial commitments required, followed by a risk analysis of a commercial mining venture in space, identifying the economic and legal risks. This leads to the recognition that the legal risks must be minimised to enable such projects to be financed. This is followed by a discussion of the principles of international space law, particularly dealing with state responsibility and international liability, as well as some of the issues arising from space mining activities. Much detail is devoted to the analysis of the content of the common heritage of mankind doctrine. The monograph then attempts to balance such interests in creating a legal and policy compromise to create a new regulatory regime.
Content Level » Research
Keywords » Asteroids - Celestial Bodies - Comets - Commercial Exploration - Common Heritage of Mankind - Economic Prospects of Mining - Exploitation Rights - Extraction of Mineral Resources - International Space Law - Lander Mission - Lex Specialis Priniciple - Mineral Resources - Moon Agreement - Outer Space Treaty - Planets - Space Law - Space Mining - Technological Prospects of Mining - The Wellington Convention
Related subjects » Extraterrestrial Physics, Space Sciences - Law - Mineralogy & Sedimentology
TABLE OF CONTENTS
List of Figures.- List of Tables.- Glossary.- Table of Abbreviations.- Table of Reports, Series and Journal Titles.- Acknowledgements.- Chapter I Introduction and Overview.- Chapter II Economic and Technical Prospects of Mining on Celestial Bodies.- Chapter III State Responsibility and Liability for Compliance with International Space Law.- Chapter IV Rights and Duties in the Commercial Exploration and Extraction of Mineral Resources on Celestial Bodies.- Chapter V Exploitation Rights: Evolving from the “Province of Mankind” to the “Common Heritage of Mankind”.- Chapter VI Meeting the Challenges and Balancing the Competing Interests in Creating a Legal and Regulatory Framework.- Chapter VII Concluding Observations.- References.- Index.
Link: Springer Books
Link: Amazon.com
17 September 2011
10 September 2011
B612 Foundation Website Update
The B612 Foundation has updated its website.
About them...
The B612 is a non-profit organization founded by a group of astronauts and scientists whose goal is to predict and prevent catastrophic asteroid impacts on Earth. B612 aims to find potentially threatening asteroids, track their trajectories, and to demonstrate the technology to alter the orbit of an asteroid in a controlled manner.
About them...
The B612 is a non-profit organization founded by a group of astronauts and scientists whose goal is to predict and prevent catastrophic asteroid impacts on Earth. B612 aims to find potentially threatening asteroids, track their trajectories, and to demonstrate the technology to alter the orbit of an asteroid in a controlled manner.
09 September 2011
SGAC Announces the Winner of the 2011 Move an Asteroid Competition ("Smart Cloud" for Asteroid Mitigation)
The Space Generation Advisory Council (SGAC) announced the winner of its 2011 Move An Asteroid International Technical Paper Competition. Here is the announcement from SGAC. The winner, Alison Gibbings, is currently is currently a PhD student at the University of Strathclyde within the Advanced Concept Laborator in Glasgow, Scotland. She will be on National Public Radio (NPR) radio show Science Friday. Here is the NPR show information.
Her proposal outlined in the paper is for a "Smart Cloud" utilizing, multiple small particles for momentum transfer for asteroid deflection.
2011 Move an Asteroid Winning Paper Abstract:
This paper presents a novel idea for the successful deflection of asteroids. Adapted initially from the kinematic impactor approach, this new concept – Smart Cloud – combines the relative benefits of ion beaming in providing a large cloud of small particles for the effective deflection and mitigation of asteroids. The cloud consists of a large number of incredibly low mass nano-size spacecraft that are released at a high relative velocity. Upon impact with the asteroid the smart cloud is shown to be highly effective in creating a large artificial drag, and therefore an associated thrust, onto the asteroid. The technique is also advantageous in avoiding the catastrophic fragmentation of the asteroid which might otherwise occur with the impact of a monolithic spacecraft and/or projectile. The impact energy of each colliding particle is significantly lower than the impact energy for disruption. . For analysis the smart cloud approach has been compared to other methods of potential deflection. This includes the low-thrust tug and the ion beaming technique. The paper will show that when the total deflection mass of the smart cloud is equivalent to the ion beaming approach, is has the advantage of significantly reducing the system mass and complexity of the spacecraft design. It is also superior in the deflection and mitigation of deep crossing asteroids.
Link: SGAC News Annoucement
Her proposal outlined in the paper is for a "Smart Cloud" utilizing, multiple small particles for momentum transfer for asteroid deflection.
2011 Move an Asteroid Winning Paper Abstract:
This paper presents a novel idea for the successful deflection of asteroids. Adapted initially from the kinematic impactor approach, this new concept – Smart Cloud – combines the relative benefits of ion beaming in providing a large cloud of small particles for the effective deflection and mitigation of asteroids. The cloud consists of a large number of incredibly low mass nano-size spacecraft that are released at a high relative velocity. Upon impact with the asteroid the smart cloud is shown to be highly effective in creating a large artificial drag, and therefore an associated thrust, onto the asteroid. The technique is also advantageous in avoiding the catastrophic fragmentation of the asteroid which might otherwise occur with the impact of a monolithic spacecraft and/or projectile. The impact energy of each colliding particle is significantly lower than the impact energy for disruption. . For analysis the smart cloud approach has been compared to other methods of potential deflection. This includes the low-thrust tug and the ion beaming technique. The paper will show that when the total deflection mass of the smart cloud is equivalent to the ion beaming approach, is has the advantage of significantly reducing the system mass and complexity of the spacecraft design. It is also superior in the deflection and mitigation of deep crossing asteroids.
Link: SGAC News Annoucement
31 August 2011
Target NEO Workshop Final Report
A recent space.com article on the final report from the Target: NEO workshop.
Selections from the article...
Developing the capability to launch human missions to asteroids would aid humanity's ability to foil a potentially devastating asteroid strike and help spur our march to Mars, a new report finds.
What's most needed to make manned asteroid missions possible, the report further concludes, is a comprehensive survey of the Near Earth Object (NEO) population, which would greatly aid planning efforts.
The new report, entitled "Target NEO: Open Global Community NEO Workshop," is anchored in views expressed by experts who gathered at George Washington University (GWU) in Washington in February. But this latest appraisal includes extensive peer review and refined findings from a number of follow-up meetings, both in the United States and abroad.
The key question posed by the GWU workshop: What information about NEOs is still needed to support a robust, sustainable human exploration program?
While this question prompted a variety of recommendations, a primary conclusion by the participants is the need for a space-based survey telescope to greatly expand the catalog of accessible asteroid targets for human exploration.
The space rock menace
There is a growing list of stakeholders supportive of NEO exploration, said Paul Abell, lead scientist for planetary small bodies at the Astromaterials Research and Exploration Science Directorate of NASA's Johnson Space Center in Houston.
"This report is timely," Abell told SPACE.com.
Small bodies have become a magnet for multiple interest groups in the U.S. and abroad, Abell said, be they space scientists, astrobiologists, planetary defense planners or NEO specialists who eye the rocky worlds as resource nodes.
For example, NASA recently selected an asteroid sample return mission called Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer, or OSIRIS-Rex. OSIRIS-Rex will be the first U.S. mission to carry samples from an asteroid back to Earth.
Japanese space officials are moving forward on their Hayabusa 2 asteroid explorer. Russia is readying its Phobos-Grunt spacecraft to explore a moon of Mars, and Canada is pressing forward on its dual-purpose microsatellite, NEOSSAT.
Then there’s the new, surprising data flooding in from NASA’s Dawn probe that’s taking a long look at Vesta, the second-largest object in the main asteroid belt between Mars and Jupiter.
"It shows you that, every time we go places, we’re always surprised and there’s so much to learn," Abell said. "That’s the fun part of science and exploration."
The "Target NEO" report points out that programs and planned missions to asteroids may be leveraged for mutual benefit in terms of data exchange. It also recommends coordination with the European Space Agency and other space agencies on a planetary defense demonstration mission.
Stepping stones to Mars
As for dispatching astronauts to asteroids, the report envisions that a target NEO will need to be discovered several years in advance to provide enough lead time to deliver robotic precursor missions, plan the human mission and deliver the crew to the chosen destination.
Abell also said that piloted flight to a NEO would hone techniques that could enable an exploration mission to the Red Planet.
"They provide good stepping stones out to Mars," Abell said.
Operating at an asteroid or Mars would be completely different than working at the moon, on the space shuttle or aboard the International Space Station.
Both asteroids and Mars, for example, would have much greater lags in communication times. So deep space missions would require the sharpening of true autonomy acumen, as well as a great deal of confidence in redundant hardware, deep space propulsion, life support gear and radiation shielding.
Link: Space.com article
Link: Target: NEO workshop final report (PDF)
Selections from the article...
Developing the capability to launch human missions to asteroids would aid humanity's ability to foil a potentially devastating asteroid strike and help spur our march to Mars, a new report finds.
What's most needed to make manned asteroid missions possible, the report further concludes, is a comprehensive survey of the Near Earth Object (NEO) population, which would greatly aid planning efforts.
The new report, entitled "Target NEO: Open Global Community NEO Workshop," is anchored in views expressed by experts who gathered at George Washington University (GWU) in Washington in February. But this latest appraisal includes extensive peer review and refined findings from a number of follow-up meetings, both in the United States and abroad.
The key question posed by the GWU workshop: What information about NEOs is still needed to support a robust, sustainable human exploration program?
While this question prompted a variety of recommendations, a primary conclusion by the participants is the need for a space-based survey telescope to greatly expand the catalog of accessible asteroid targets for human exploration.
The space rock menace
There is a growing list of stakeholders supportive of NEO exploration, said Paul Abell, lead scientist for planetary small bodies at the Astromaterials Research and Exploration Science Directorate of NASA's Johnson Space Center in Houston.
"This report is timely," Abell told SPACE.com.
Small bodies have become a magnet for multiple interest groups in the U.S. and abroad, Abell said, be they space scientists, astrobiologists, planetary defense planners or NEO specialists who eye the rocky worlds as resource nodes.
For example, NASA recently selected an asteroid sample return mission called Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer, or OSIRIS-Rex. OSIRIS-Rex will be the first U.S. mission to carry samples from an asteroid back to Earth.
Japanese space officials are moving forward on their Hayabusa 2 asteroid explorer. Russia is readying its Phobos-Grunt spacecraft to explore a moon of Mars, and Canada is pressing forward on its dual-purpose microsatellite, NEOSSAT.
Then there’s the new, surprising data flooding in from NASA’s Dawn probe that’s taking a long look at Vesta, the second-largest object in the main asteroid belt between Mars and Jupiter.
"It shows you that, every time we go places, we’re always surprised and there’s so much to learn," Abell said. "That’s the fun part of science and exploration."
The "Target NEO" report points out that programs and planned missions to asteroids may be leveraged for mutual benefit in terms of data exchange. It also recommends coordination with the European Space Agency and other space agencies on a planetary defense demonstration mission.
Stepping stones to Mars
As for dispatching astronauts to asteroids, the report envisions that a target NEO will need to be discovered several years in advance to provide enough lead time to deliver robotic precursor missions, plan the human mission and deliver the crew to the chosen destination.
Abell also said that piloted flight to a NEO would hone techniques that could enable an exploration mission to the Red Planet.
"They provide good stepping stones out to Mars," Abell said.
Operating at an asteroid or Mars would be completely different than working at the moon, on the space shuttle or aboard the International Space Station.
Both asteroids and Mars, for example, would have much greater lags in communication times. So deep space missions would require the sharpening of true autonomy acumen, as well as a great deal of confidence in redundant hardware, deep space propulsion, life support gear and radiation shielding.
Link: Space.com article
Link: Target: NEO workshop final report (PDF)
30 August 2011
PR on Recent Workshop on Planetary Defense Policy Workshop with SWF/NASA/UN/ASE
From the press release from Secure World Foundation...
A workshop has brought together leading representatives from space agencies and international experts to discuss key issues related to global response and cooperation in the event of a Near Earth Object (NEO) impact threat to Earth.
The gathering of specialists took place August 25-26 in Pasadena, California. The meeting was co-organized and co-sponsored by Action Team-14, part of the United Nations Committee on the Peaceful Uses of Outer Space (UN COPUOS) Scientific and Technical Subcommittee, Secure World Foundation (SWF), and the Association of Space Explorers (ASE) that represents over 350 individuals from 35 nations who have flown in space.
The supporting agency host of the meeting was the National Aeronautics and Space Administration (NASA) Near Earth Object Observations Program Office.
This recent workshop is a follow-up to previous meetings that took place last year in Mexico City to discuss a NEO Information, Analysis, and Warning Network (IAWN) and in Darmstadt, Germany to confer about a NEO Mission Planning and Operations Group, or MPOG, to plan, organize, and conduct any necessary missions to threatening asteroids.
Decisive step: set of recommendations
“As we now have the technological capacity, we should be able to prevent the threat of an asteroid impact on Earth or mitigate its consequences,” said Dr. Sergio Camacho, Secretary General of the Regional Centre for Space Science and Technology Education in Latin America and the Caribbean (CRECTEALC) in Mexico City. Camacho is a former Director of the United Nations Office for Outer Space Affairs, a post that he held from 2002 to 2007.
“I am very pleased with the progress made at this workshop towards establishing a space agency Mission Planning and Operations Group (MPOG) to plan, prepare and respond, if need be, to an asteroid threat,” Camacho said.
Preparing a draft Terms of Reference for such a group, with the participation of four space agencies, is a decisive step in this direction, Comacho added.
These results, together with those garnered from previous policy workshops -- also co-sponsored by Secure World Foundation -- on establishing an IAWN, an MPOG, and results to date from the multi-year work plan of the Action Team-14 on Near Earth Objects of the United Nations Committee on the Peaceful Uses of Outer Space, will result in February 2013 with a set of recommendations on which the Committee can act.
“I am also very pleased by the progress that we made in preparing these recommendations,” Comacho said. “By joining and coordinating efforts, the international community will be much better prepared to prevent the devastating consequences of an asteroid impact on Earth.”
Substantial progress
“This workshop made substantial progress toward an international interagency plan to mitigate the damaging effects of an asteroid strike against Earth. It also made headway in an effort to develop an overall international governance model for the response to a threatening Near Earth Object,” said Dr. Ray A. Williamson, Executive Director of Secure World Foundation.
The Association of Space Explorers has been promoting international efforts to plan for averting a future asteroid impact for more than five years, and last week’s Mission Planning and Operations Group meeting shows the world’s space agencies are moving closer to cooperative action, said Tom Jones, former NASA shuttle astronaut and current Chair of the ASE Committee on Near-Earth Objects.
Jones said that the “rules of the road” for the group should lead to joint technology development to deflect a rogue asteroid.
“What’s needed now is top-level agency endorsement of international planning and research, leading to a space demonstration of how we would change the course of an asteroid,” Jones said. “That’s the goal, so we can be ready for a hazardous asteroid down the road.”
Link: Press Release
A workshop has brought together leading representatives from space agencies and international experts to discuss key issues related to global response and cooperation in the event of a Near Earth Object (NEO) impact threat to Earth.
The gathering of specialists took place August 25-26 in Pasadena, California. The meeting was co-organized and co-sponsored by Action Team-14, part of the United Nations Committee on the Peaceful Uses of Outer Space (UN COPUOS) Scientific and Technical Subcommittee, Secure World Foundation (SWF), and the Association of Space Explorers (ASE) that represents over 350 individuals from 35 nations who have flown in space.
The supporting agency host of the meeting was the National Aeronautics and Space Administration (NASA) Near Earth Object Observations Program Office.
This recent workshop is a follow-up to previous meetings that took place last year in Mexico City to discuss a NEO Information, Analysis, and Warning Network (IAWN) and in Darmstadt, Germany to confer about a NEO Mission Planning and Operations Group, or MPOG, to plan, organize, and conduct any necessary missions to threatening asteroids.
Decisive step: set of recommendations
“As we now have the technological capacity, we should be able to prevent the threat of an asteroid impact on Earth or mitigate its consequences,” said Dr. Sergio Camacho, Secretary General of the Regional Centre for Space Science and Technology Education in Latin America and the Caribbean (CRECTEALC) in Mexico City. Camacho is a former Director of the United Nations Office for Outer Space Affairs, a post that he held from 2002 to 2007.
“I am very pleased with the progress made at this workshop towards establishing a space agency Mission Planning and Operations Group (MPOG) to plan, prepare and respond, if need be, to an asteroid threat,” Camacho said.
Preparing a draft Terms of Reference for such a group, with the participation of four space agencies, is a decisive step in this direction, Comacho added.
These results, together with those garnered from previous policy workshops -- also co-sponsored by Secure World Foundation -- on establishing an IAWN, an MPOG, and results to date from the multi-year work plan of the Action Team-14 on Near Earth Objects of the United Nations Committee on the Peaceful Uses of Outer Space, will result in February 2013 with a set of recommendations on which the Committee can act.
“I am also very pleased by the progress that we made in preparing these recommendations,” Comacho said. “By joining and coordinating efforts, the international community will be much better prepared to prevent the devastating consequences of an asteroid impact on Earth.”
Substantial progress
“This workshop made substantial progress toward an international interagency plan to mitigate the damaging effects of an asteroid strike against Earth. It also made headway in an effort to develop an overall international governance model for the response to a threatening Near Earth Object,” said Dr. Ray A. Williamson, Executive Director of Secure World Foundation.
The Association of Space Explorers has been promoting international efforts to plan for averting a future asteroid impact for more than five years, and last week’s Mission Planning and Operations Group meeting shows the world’s space agencies are moving closer to cooperative action, said Tom Jones, former NASA shuttle astronaut and current Chair of the ASE Committee on Near-Earth Objects.
Jones said that the “rules of the road” for the group should lead to joint technology development to deflect a rogue asteroid.
“What’s needed now is top-level agency endorsement of international planning and research, leading to a space demonstration of how we would change the course of an asteroid,” Jones said. “That’s the goal, so we can be ready for a hazardous asteroid down the road.”
Link: Press Release
New Papers on low delta-V asteroids, asteroid mission measurement requirements, Human mission NEO targets, and detection of radiation pressure
Several new papers.
PAPER REFERENCE:
Physical characterisation of low delta-V asteroid (175706) 1996 FG3
Authors: Stephen D. Wolters, Ben Rozitis, Samuel R. Duddy, Stephen C. Lowry, Simon F. Green, Colin Snodgrass, Olivier R. Hainaut, Paul Weissman (Submitted on 08 Aug 2011)
Abstract: Asteroid (175706) 1996 FG3 is a binary asteroid and the baseline target for the proposed MarcoPolo-R sample-return mission. We present thermal IR photometry obtained with the ESO VLT+VISIR together with optical photometry obtained with the ESO NTT+EFOSC2 . An absolute visual magnitude H_V = 17.833 \pm 0.024 and phase parameter G = -0.041 \pm 0.005 is derived. The Near-Earth Asteroid Thermal Model (NEATM) has been fitted to the measured fluxes to derive a geometric visual albedo p_v = 0.046 \pm 0.014, effective diameter at the observed aspect D_eff = 1.68 \pm 0.25 km, and beaming parameter {\eta} = 1.15 for phase angle {\alpha} = 11.7{\deg}. The Advanced Thermophysical Model (ATPM) has been fitted to the measured fluxes to derive a more accurate effective diameter D_eff = 1.71 \pm 0.07 km and albedo p_v = 0.044 \pm 0.004. Based on the ATPM results, assuming the same albedo for primary and secondary, we derive a primary mean spherical diameter D_p = (1.69 +0.18/-0.12) km, secondary diameter D_s = 0.51 \pm 0.03 km, and a secondary orbital semi-major axis a = (2.8 +1.7/-0.7) km. A low surface thermal inertia {\Gamma} = 120 \pm 50 J m^-2 s^-1/2 K^-1 was also derived, suggesting a dusty surface and raising questions as to the binary formation mechanism of this asteroid. These physical properties are used to predict a Yarkovsky drift in semi-major axis of (-60 +31/-45) m yr-1.
Cite as: 1108.1831v1 [astro-ph.IM]
Link: Paper (PDF format)
PAPER REFERENCE:
Measurement requirements for a near-Earth asteroid impact mitigation demonstration mission
Authors: Stephen D. Wolters, Andrew J. Ball, Nigel Wells, Christopher Saunders, Neil McBride (Submitted on 21 Jul 2011)
Abstract: A concept for an Impact Mitigation Preparation Mission, called Don Quijote, is to send two spacecraft to a Near-Earth Asteroid (NEA): an Orbiter and an Impactor. The Impactor collides with the asteroid while the Orbiter measures the resulting change in the asteroid's orbit, by means of a Radio Science Experiment (RSE) carried out before and after impact. Three parallel Phase A studies on Don Quijote were carried out for the European Space Agency: the research presented here reflects outcomes of the study by QinetiQ. We discuss the mission objectives with regards to the prioritisation of payload instruments, with emphasis on the interpretation of the impact. The Radio Science Experiment is described and it is examined how solar radiation pressure may increase the uncertainty in measuring the orbit of the target asteroid. It is determined that to measure the change in orbit accurately a thermal IR spectrometer is mandatory, to measure the Yarkovsky effect. The advantages of having a laser altimeter are discussed. The advantages of a dedicated wide-angle impact camera are discussed and the field-of-view is initially sized through a simple model of the impact.
Cite as: 1107.4229v1 [astro-ph.IM]
Link: Paper (PDF format)
PAPER REFERENCE:
Ultra-Low Delta-v Objects and the Human Exploration of Asteroids
Authors: Martin Elvis, Jonathan McDowell, Jeffrey A. Hoffman, Richard P. Binzel (Submitted on 20 May 2011 (v1), last revised 15 Jun 2011 (this version, v2))
Abstract: Missions to near-Earth objects (NEOs) are key destinations in NASA's new "Flexible Path" approach. NEOs are also of interest for science, for the hazards they pose, and for their resources. We emphasize the importance of ultra-low delta-v from LEO to NEO rendezvous as a target selection criterion, as this choice can greatly increase the payload to the NEO. Few such ultra-low delta-v NEOs are currently known; only 65 of the 6699 known NEOs (March2010) have delta-v <4.5 km/s, 2/3 of typical LEO-NEO delta-v. Even these are small and hard to recover. Other criteria - short transit times, long launch windows, a robust abort capability, and a safe environment for proximity operations - will further limit the list of accessible objects. Potentially there are at least an order of magnitude more ultra-low delta v NEOs but, to find them all on a short enough timescale (before 2025) requires a dedicated survey in the optical or mid-IR, optimally from a Venus-like orbit because of the short synodic period for NEOs in that orbit, plus long arc determination of their orbits.
Cite as: 1105.4152v2 [astro-ph.IM]
Link: Paper (PDF format)
PAPER REFERENCE:
Detection of radiation pressure acting on 2009 BD
Authors: Marco Micheli, David J. Tholen, Garrett T. Elliott (Submitted on 03 Jun 2011)
Abstract: We report the direct detection of radiation pressure on the asteroid 2009 BD, one of the smallest multi-opposition near-Earth objects currently known, with H ~ 28.4. Under the purely gravitational model of NEODyS the object is currently considered a possible future impactor, with impact solutions starting in 2071. The detection of a radiation-related acceleration allows us to estimate an Area to Mass Ratio (AMR) for the object, that can be converted (under some assumptions) into a range of possible values for its average density. Our result AMR = (2.97 \pm 0.33) x 10^(-4) m^2 kg^(-1) is compatible with the object being of natural origin, and it is narrow enough to exclude a man-made nature. The possible origin of this object, its future observability, and the importance of radiation pressure in the impact monitoring process, are also discussed.
Cite as: 1106.0564v1 [astro-ph.IM]
Link: Paper (PDF format)
PAPER REFERENCE:
Physical characterisation of low delta-V asteroid (175706) 1996 FG3
Authors: Stephen D. Wolters, Ben Rozitis, Samuel R. Duddy, Stephen C. Lowry, Simon F. Green, Colin Snodgrass, Olivier R. Hainaut, Paul Weissman (Submitted on 08 Aug 2011)
Abstract: Asteroid (175706) 1996 FG3 is a binary asteroid and the baseline target for the proposed MarcoPolo-R sample-return mission. We present thermal IR photometry obtained with the ESO VLT+VISIR together with optical photometry obtained with the ESO NTT+EFOSC2 . An absolute visual magnitude H_V = 17.833 \pm 0.024 and phase parameter G = -0.041 \pm 0.005 is derived. The Near-Earth Asteroid Thermal Model (NEATM) has been fitted to the measured fluxes to derive a geometric visual albedo p_v = 0.046 \pm 0.014, effective diameter at the observed aspect D_eff = 1.68 \pm 0.25 km, and beaming parameter {\eta} = 1.15 for phase angle {\alpha} = 11.7{\deg}. The Advanced Thermophysical Model (ATPM) has been fitted to the measured fluxes to derive a more accurate effective diameter D_eff = 1.71 \pm 0.07 km and albedo p_v = 0.044 \pm 0.004. Based on the ATPM results, assuming the same albedo for primary and secondary, we derive a primary mean spherical diameter D_p = (1.69 +0.18/-0.12) km, secondary diameter D_s = 0.51 \pm 0.03 km, and a secondary orbital semi-major axis a = (2.8 +1.7/-0.7) km. A low surface thermal inertia {\Gamma} = 120 \pm 50 J m^-2 s^-1/2 K^-1 was also derived, suggesting a dusty surface and raising questions as to the binary formation mechanism of this asteroid. These physical properties are used to predict a Yarkovsky drift in semi-major axis of (-60 +31/-45) m yr-1.
Cite as: 1108.1831v1 [astro-ph.IM]
Link: Paper (PDF format)
PAPER REFERENCE:
Measurement requirements for a near-Earth asteroid impact mitigation demonstration mission
Authors: Stephen D. Wolters, Andrew J. Ball, Nigel Wells, Christopher Saunders, Neil McBride (Submitted on 21 Jul 2011)
Abstract: A concept for an Impact Mitigation Preparation Mission, called Don Quijote, is to send two spacecraft to a Near-Earth Asteroid (NEA): an Orbiter and an Impactor. The Impactor collides with the asteroid while the Orbiter measures the resulting change in the asteroid's orbit, by means of a Radio Science Experiment (RSE) carried out before and after impact. Three parallel Phase A studies on Don Quijote were carried out for the European Space Agency: the research presented here reflects outcomes of the study by QinetiQ. We discuss the mission objectives with regards to the prioritisation of payload instruments, with emphasis on the interpretation of the impact. The Radio Science Experiment is described and it is examined how solar radiation pressure may increase the uncertainty in measuring the orbit of the target asteroid. It is determined that to measure the change in orbit accurately a thermal IR spectrometer is mandatory, to measure the Yarkovsky effect. The advantages of having a laser altimeter are discussed. The advantages of a dedicated wide-angle impact camera are discussed and the field-of-view is initially sized through a simple model of the impact.
Cite as: 1107.4229v1 [astro-ph.IM]
Link: Paper (PDF format)
PAPER REFERENCE:
Ultra-Low Delta-v Objects and the Human Exploration of Asteroids
Authors: Martin Elvis, Jonathan McDowell, Jeffrey A. Hoffman, Richard P. Binzel (Submitted on 20 May 2011 (v1), last revised 15 Jun 2011 (this version, v2))
Abstract: Missions to near-Earth objects (NEOs) are key destinations in NASA's new "Flexible Path" approach. NEOs are also of interest for science, for the hazards they pose, and for their resources. We emphasize the importance of ultra-low delta-v from LEO to NEO rendezvous as a target selection criterion, as this choice can greatly increase the payload to the NEO. Few such ultra-low delta-v NEOs are currently known; only 65 of the 6699 known NEOs (March2010) have delta-v <4.5 km/s, 2/3 of typical LEO-NEO delta-v. Even these are small and hard to recover. Other criteria - short transit times, long launch windows, a robust abort capability, and a safe environment for proximity operations - will further limit the list of accessible objects. Potentially there are at least an order of magnitude more ultra-low delta v NEOs but, to find them all on a short enough timescale (before 2025) requires a dedicated survey in the optical or mid-IR, optimally from a Venus-like orbit because of the short synodic period for NEOs in that orbit, plus long arc determination of their orbits.
Cite as: 1105.4152v2 [astro-ph.IM]
Link: Paper (PDF format)
PAPER REFERENCE:
Detection of radiation pressure acting on 2009 BD
Authors: Marco Micheli, David J. Tholen, Garrett T. Elliott (Submitted on 03 Jun 2011)
Abstract: We report the direct detection of radiation pressure on the asteroid 2009 BD, one of the smallest multi-opposition near-Earth objects currently known, with H ~ 28.4. Under the purely gravitational model of NEODyS the object is currently considered a possible future impactor, with impact solutions starting in 2071. The detection of a radiation-related acceleration allows us to estimate an Area to Mass Ratio (AMR) for the object, that can be converted (under some assumptions) into a range of possible values for its average density. Our result AMR = (2.97 \pm 0.33) x 10^(-4) m^2 kg^(-1) is compatible with the object being of natural origin, and it is narrow enough to exclude a man-made nature. The possible origin of this object, its future observability, and the importance of radiation pressure in the impact monitoring process, are also discussed.
Cite as: 1106.0564v1 [astro-ph.IM]
Link: Paper (PDF format)
29 August 2011
Paper: Capturing Near Earth Objects
From the MIT Technology Review article of a new paper from Baoyin, et al called "Capturing Near Earth Objects"...
Most of the discussion about near Earth asteroids focuses on whether they represent a threat to Earth and what to do take if they turn out to be heading our way. But today, Hexi Baoyin and pals at Tsinghua University in Beijing offer a different take. The question they ask is how to place an asteroid in orbit around the Earth. Their conclusion is a little surprising. They say it's relatively straightforward to nudge a small asteroid in our direction. They've even discovered a number of candidates nearby that we might want to bring as little closer. Their inspiration is a phenomenon that astronomers have noticed with Jupiter. Every now and again, the gas giant captures a nearby object, which hangs around for a few years and then wanders off into space. A good example is the comet Oterma which went into orbit about Jupiter in1936 before heading off into the Solar System two years later. Could a similar thing happen to Earth, ask Baoyin and co. Having studied the orbits of the 6000 known near Earth objects (NEO), they say the short answer is no. None of them will come close enough for Earth to capture. However, a few of these objects will come maddeningly close. So near, in fact, that a small nudge would send them into Earth orbit. "When such an NEO approaches Earth, it is possible to change its orbit energy...to make the NEO become a small satellite of the Earth," they say. A particularly good candidate is a 10-meter object called 2008EA9 which will pass within a million kilometres or so of Earth in 2049. 2008EA9 has a very similar orbital velocity as Earth's. Baoyin and co calculate that it could be fired into Earth orbit by changing its velocity by 410 metres per second. That's tiny. This nudge should place the asteroid in an orbit at about twice the distance of the Moon. From there it can be studied and mined, they say. Just like Oterma's, this orbit is likely to be temporary so 2008EA9 will probably wander off into the heavens after a few years.
PAPER REFERENCE:
Capturing Near Earth Objects
Authors: Hexi Baoyin, Yang Chen, Junfeng Li (Submitted on 24 Aug 2011)
Abstract: Recently, Near Earth Objects (NEOs) have been attracting great attention, and thousands of NEOs have been found to date. This paper examines the NEOs' orbital dynamics using the framework of an accurate solar system model and a Sun-Earth-NEO three-body system when the NEOs are close to Earth to search for NEOs with low-energy orbits. It is possible for such an NEO to be temporarily captured by Earth; its orbit would thereby be changed and it would become an Earth-orbiting object after a small increase in its velocity. From the point of view of the Sun-Earth-NEO restricted three-body system, it is possible for an NEO whose Jacobian constant is slightly lower than C1 and higher than C3 to be temporarily captured by Earth. When such an NEO approaches Earth, it is possible to change its orbit energy to close up the zero velocity surface of the three-body system at point L1 and make the NEO become a small satellite of the Earth. Some such NEOs were found; the best example only required a 410m/s increase in velocity.
Cite as: 1108.4767v1 [astro-ph.IM]
Link: MIT Technology Review Article
Link: Paper (PDF format)
Most of the discussion about near Earth asteroids focuses on whether they represent a threat to Earth and what to do take if they turn out to be heading our way. But today, Hexi Baoyin and pals at Tsinghua University in Beijing offer a different take. The question they ask is how to place an asteroid in orbit around the Earth. Their conclusion is a little surprising. They say it's relatively straightforward to nudge a small asteroid in our direction. They've even discovered a number of candidates nearby that we might want to bring as little closer. Their inspiration is a phenomenon that astronomers have noticed with Jupiter. Every now and again, the gas giant captures a nearby object, which hangs around for a few years and then wanders off into space. A good example is the comet Oterma which went into orbit about Jupiter in1936 before heading off into the Solar System two years later. Could a similar thing happen to Earth, ask Baoyin and co. Having studied the orbits of the 6000 known near Earth objects (NEO), they say the short answer is no. None of them will come close enough for Earth to capture. However, a few of these objects will come maddeningly close. So near, in fact, that a small nudge would send them into Earth orbit. "When such an NEO approaches Earth, it is possible to change its orbit energy...to make the NEO become a small satellite of the Earth," they say. A particularly good candidate is a 10-meter object called 2008EA9 which will pass within a million kilometres or so of Earth in 2049. 2008EA9 has a very similar orbital velocity as Earth's. Baoyin and co calculate that it could be fired into Earth orbit by changing its velocity by 410 metres per second. That's tiny. This nudge should place the asteroid in an orbit at about twice the distance of the Moon. From there it can be studied and mined, they say. Just like Oterma's, this orbit is likely to be temporary so 2008EA9 will probably wander off into the heavens after a few years.
PAPER REFERENCE:
Capturing Near Earth Objects
Authors: Hexi Baoyin, Yang Chen, Junfeng Li (Submitted on 24 Aug 2011)
Abstract: Recently, Near Earth Objects (NEOs) have been attracting great attention, and thousands of NEOs have been found to date. This paper examines the NEOs' orbital dynamics using the framework of an accurate solar system model and a Sun-Earth-NEO three-body system when the NEOs are close to Earth to search for NEOs with low-energy orbits. It is possible for such an NEO to be temporarily captured by Earth; its orbit would thereby be changed and it would become an Earth-orbiting object after a small increase in its velocity. From the point of view of the Sun-Earth-NEO restricted three-body system, it is possible for an NEO whose Jacobian constant is slightly lower than C1 and higher than C3 to be temporarily captured by Earth. When such an NEO approaches Earth, it is possible to change its orbit energy to close up the zero velocity surface of the three-body system at point L1 and make the NEO become a small satellite of the Earth. Some such NEOs were found; the best example only required a 410m/s increase in velocity.
Cite as: 1108.4767v1 [astro-ph.IM]
Link: MIT Technology Review Article
Link: Paper (PDF format)
28 August 2011
Job Posting in Planetary Defense: Minor Planet Center (MPC) looking for IT Specialist
An IT specialist job announcement from the Minor Planet Center (MPC).
From Wikipedia: "Under the auspices of the International Astronomical Union, the MPC is the official organization in charge of collecting observational data for minor planets (asteroids) and comets, calculating their orbits and publishing this information via the Minor Planet Circulars." The MPC is part of the Smithsonian Astrophysical Observatory (SAO) at the Harvard-Smithsonian Center for Astrophysics.
Here is the MPC link as well as the USAJOBS link. Here is the listing:
SMITHSONIAN ASTROPHYSICAL OBSERVATORY
HR: Employment Opportunities
Job posting 11-59
Opening date: August 26, 2011
Closing date: September 16, 2011
TITLE: IT Specialist, IS-2210 (SYSADMIN/APPSW), Grade 13, $89,449 to $116,282/yr
TYPE OF POSITION: Trust Fund (non-federal) Indefinite
DIVISION: - Minor Planet Center, Solar, Stellar and Planetary Sciences Division
LOCATION: Cambridge, Massachusetts
AREA OF CONSIDERATION: All qualified candidates First consideration may be made 14 days after the opening date.
DUTIES: Duties may include but are not limited to: implementing all aspects of the software development lifecycle, including requirements generation, design, code, verification and test, and maintenance; interfacing with science staff at the highest project levels to obtain information regarding their needs as the user of the system; designing software following the Minor Planet Center (MPC) software design standards, applicable vendor's literature, and established practices; overseeing the translation of design into code within the MPC programming team and coordinating software development activities between subsystem teams to ensure design consistency; designing software subsystems and components, coding and debugging complex programs to support mission planning, scientific data analysis and reduction, and data archiving and retrieval on workstation computer and image display systems; verifying and testing all generated software and maintaining code as part of an overall system and overseeing these activities within the team.
QUALIFICATIONS : For all positions individuals must have IT-related experience demonstrating each of the four competencies listed below.
1. Attention to Detail - Is thorough when performing work and conscientious about attending to detail.
2. Customer Service - Works with clients and customers (that is, any individuals who use or receive the services or products that your work unit produces, including the general public, individuals who work in the agency, other agencies, or organizations outside the Government) to assess their needs, provide information or assistance, resolve their problems, or satisfy their expectations; knows about available products and services; is committed to providing quality products and services.
3. Oral Communication - Expresses information (for example, ideas or facts) to individuals or groups effectively, taking into account the audience and nature of the information (for example, technical, sensitive, controversial); makes clear and convincing oral presentations; listens to others, attends to nonverbal cues, and responds appropriately.
4. Problem Solving - Identifies problems; determines accuracy and relevance of information; uses sound judgment to generate and evaluate alternatives, and to make recommendations. In addition to the basic requirements listed above applicants must possess a minimum of one year of specialized experience equivalent to at least the grade 12 in the normal line of progression for this occupation which should demonstrate mastery of and skill in applying the various phases of the system software development lifecycles, including requirements generation, design, code, verification and test, systems integration, and maintenance; knowledge of the physical systems for which software is being developed to be able to define scientific requirements and develop software requirements; knowledge of FORTRAN, C, scripting languages, Unix and Linux; knowledge of the current state of system software technology and related computer equipment in the assigned area; knowledge of mathematics, sufficient to be able to communicate with scientists and engineers concerning calculations and algorithms; knowledge of image handling, graphics, display systems, and database management systems; ability to develop software at the subsystem level while conforming to standards; ability to assess emerging technologies as alternatives to current practices; ability to provide expert technical guidance to management and other staff; ability to present findings to management and staff on complex issues; and the ability to communicate both orally and in writing.
APPLICATION PROCEDURE: We will only accept applications on line for this position.
For a copy of the complete vacancy announcement and how to apply, visit: USAJOBS
The Smithsonian Astrophysical Observatory is an equal opportunity employer committed to diversity in our workplace.
Link: MPC Job Posting
From Wikipedia: "Under the auspices of the International Astronomical Union, the MPC is the official organization in charge of collecting observational data for minor planets (asteroids) and comets, calculating their orbits and publishing this information via the Minor Planet Circulars." The MPC is part of the Smithsonian Astrophysical Observatory (SAO) at the Harvard-Smithsonian Center for Astrophysics.
Here is the MPC link as well as the USAJOBS link. Here is the listing:
SMITHSONIAN ASTROPHYSICAL OBSERVATORY
HR: Employment Opportunities
Job posting 11-59
Opening date: August 26, 2011
Closing date: September 16, 2011
TITLE: IT Specialist, IS-2210 (SYSADMIN/APPSW), Grade 13, $89,449 to $116,282/yr
TYPE OF POSITION: Trust Fund (non-federal) Indefinite
DIVISION: - Minor Planet Center, Solar, Stellar and Planetary Sciences Division
LOCATION: Cambridge, Massachusetts
AREA OF CONSIDERATION: All qualified candidates First consideration may be made 14 days after the opening date.
DUTIES: Duties may include but are not limited to: implementing all aspects of the software development lifecycle, including requirements generation, design, code, verification and test, and maintenance; interfacing with science staff at the highest project levels to obtain information regarding their needs as the user of the system; designing software following the Minor Planet Center (MPC) software design standards, applicable vendor's literature, and established practices; overseeing the translation of design into code within the MPC programming team and coordinating software development activities between subsystem teams to ensure design consistency; designing software subsystems and components, coding and debugging complex programs to support mission planning, scientific data analysis and reduction, and data archiving and retrieval on workstation computer and image display systems; verifying and testing all generated software and maintaining code as part of an overall system and overseeing these activities within the team.
QUALIFICATIONS : For all positions individuals must have IT-related experience demonstrating each of the four competencies listed below.
1. Attention to Detail - Is thorough when performing work and conscientious about attending to detail.
2. Customer Service - Works with clients and customers (that is, any individuals who use or receive the services or products that your work unit produces, including the general public, individuals who work in the agency, other agencies, or organizations outside the Government) to assess their needs, provide information or assistance, resolve their problems, or satisfy their expectations; knows about available products and services; is committed to providing quality products and services.
3. Oral Communication - Expresses information (for example, ideas or facts) to individuals or groups effectively, taking into account the audience and nature of the information (for example, technical, sensitive, controversial); makes clear and convincing oral presentations; listens to others, attends to nonverbal cues, and responds appropriately.
4. Problem Solving - Identifies problems; determines accuracy and relevance of information; uses sound judgment to generate and evaluate alternatives, and to make recommendations. In addition to the basic requirements listed above applicants must possess a minimum of one year of specialized experience equivalent to at least the grade 12 in the normal line of progression for this occupation which should demonstrate mastery of and skill in applying the various phases of the system software development lifecycles, including requirements generation, design, code, verification and test, systems integration, and maintenance; knowledge of the physical systems for which software is being developed to be able to define scientific requirements and develop software requirements; knowledge of FORTRAN, C, scripting languages, Unix and Linux; knowledge of the current state of system software technology and related computer equipment in the assigned area; knowledge of mathematics, sufficient to be able to communicate with scientists and engineers concerning calculations and algorithms; knowledge of image handling, graphics, display systems, and database management systems; ability to develop software at the subsystem level while conforming to standards; ability to assess emerging technologies as alternatives to current practices; ability to provide expert technical guidance to management and other staff; ability to present findings to management and staff on complex issues; and the ability to communicate both orally and in writing.
APPLICATION PROCEDURE: We will only accept applications on line for this position.
For a copy of the complete vacancy announcement and how to apply, visit: USAJOBS
The Smithsonian Astrophysical Observatory is an equal opportunity employer committed to diversity in our workplace.
Link: MPC Job Posting
26 August 2011
Applications for the GSA Planetary Science Division’s Eugene M. Shoemaker Impact Cratering Award are due September 9, 2011
From Dr. David A. Kring, Ph.D. at the Center for Lunar Science & Exploration at the USRA – Lunar and Planetary Institute...
Applications for the GSA Planetary Science Division’s Eugene M. Shoemaker Impact Cratering Award are due September 9, 2011.
The Eugene M. Shoemaker Impact Cratering Award is for undergraduate or graduate students, of any nationality, working in any country, in the disciplines of geology, geophysics, geochemistry, astronomy, or biology. The award, which will include $2500, is to be applied for the study of impact craters, either on Earth or on the other solid bodies in the solar system. Areas of study may include but shall not necessarily be limited to impact cratering processes; the bodies (asteroidal or cometary) that make the impacts; or the geological, chemical, or biological results of impact cratering. Details about the award as well as an application form for interested students can be found here.
Link: Shoemaker Award Page
Applications for the GSA Planetary Science Division’s Eugene M. Shoemaker Impact Cratering Award are due September 9, 2011.
The Eugene M. Shoemaker Impact Cratering Award is for undergraduate or graduate students, of any nationality, working in any country, in the disciplines of geology, geophysics, geochemistry, astronomy, or biology. The award, which will include $2500, is to be applied for the study of impact craters, either on Earth or on the other solid bodies in the solar system. Areas of study may include but shall not necessarily be limited to impact cratering processes; the bodies (asteroidal or cometary) that make the impacts; or the geological, chemical, or biological results of impact cratering. Details about the award as well as an application form for interested students can be found here.
Link: Shoemaker Award Page
22 August 2011
Next Pixar Film in 2013: Earth if K-T Extinction Event Did Not Happen
The next Pixar film will involve a scenario where the K-T extinction event did not happen, and the resulting consequences for evolution on planet Earth. From the article...
Pixar films with explore two new worlds in two upcoming films - the land of dinosaurs and the world inside the human mind - filmmakers announced at the D23 Expo 2011 Saturday.
The fan exposition in Anaheim, Calif., featured the announcement of the two yet untitled movies as executives promoted the entire Disney/Pixar slate.
The untitled dinosaur film will be released in the holiday season of 2013. Bob Peterson, who co-directed and voiced Dug the dog in the monster Pixar hit Up, will direct the new movie. He said he was inspired by a childhood visit to the World's Fair in New York where he saw animatronic dinosaurs created by Walt Disney. "It made a big impression on me," he said.
Peterson said the premise of the film will take aim at the notion that dinosaurs were made instinct by a giant asteroid hitting the Earth. "In this film, the asteroid missed the Earth and dinosaurs continued to live," he says.
Link: USA Today article
Pixar films with explore two new worlds in two upcoming films - the land of dinosaurs and the world inside the human mind - filmmakers announced at the D23 Expo 2011 Saturday.
The fan exposition in Anaheim, Calif., featured the announcement of the two yet untitled movies as executives promoted the entire Disney/Pixar slate.
The untitled dinosaur film will be released in the holiday season of 2013. Bob Peterson, who co-directed and voiced Dug the dog in the monster Pixar hit Up, will direct the new movie. He said he was inspired by a childhood visit to the World's Fair in New York where he saw animatronic dinosaurs created by Walt Disney. "It made a big impression on me," he said.
Peterson said the premise of the film will take aim at the notion that dinosaurs were made instinct by a giant asteroid hitting the Earth. "In this film, the asteroid missed the Earth and dinosaurs continued to live," he says.
Link: USA Today article
21 August 2011
Masters Thesis: Design of a Surface Albedo Modification Payload for Near Earth Asteroid (NEA) Mitigation
A new Masters thesis paper from student Shen Ge at Texas A&M University called "Design of a Surface Albedo Modification Payload for Near Earth Asteroid (NEA) Mitigation".
PAPER REFERENCE:
Design of a Surface Albedo Modification Payload for Near Earth Asteroid (NEA) Mitigation
Authors: Shen Ge
Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Aerospace Engineering (August 2011)
Abstract: The development of the Surface Albedo Treatment System (SATS) onboard a spacecraft mission to the near earth asteroid (NEA) Apophis in 2012 is an innovative concept of deflecting NEAs from possible impact with the Earth through altering the Yarkovsky effect, a non-secular force in the solar system due to uneven surface thermal emission most profoundly affecting small rotating bodies subjected to sunlight. Though this force is small, its magnitude can be dramatic if extended over a period of time and if it uses the close approach of an asteroid near Earth to magnify the perturbation. The payload dispenses colored powder called albedo changing particles (ACPs) onto the surface changing its albedo and indirectly the surface temperature which changes the Yarkovsky effect. This study gives an in-depth description of both computational and experimental parts of the design of this system with primary focus on initial ground test setup. The initial experiments proposed to design the SATS is outlined in detail and justified by the mission criterion of interest as well as modeling the actual dispersal on the surface.
Link: Thesis (PDF)
PAPER REFERENCE:
Design of a Surface Albedo Modification Payload for Near Earth Asteroid (NEA) Mitigation
Authors: Shen Ge
Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Aerospace Engineering (August 2011)
Abstract: The development of the Surface Albedo Treatment System (SATS) onboard a spacecraft mission to the near earth asteroid (NEA) Apophis in 2012 is an innovative concept of deflecting NEAs from possible impact with the Earth through altering the Yarkovsky effect, a non-secular force in the solar system due to uneven surface thermal emission most profoundly affecting small rotating bodies subjected to sunlight. Though this force is small, its magnitude can be dramatic if extended over a period of time and if it uses the close approach of an asteroid near Earth to magnify the perturbation. The payload dispenses colored powder called albedo changing particles (ACPs) onto the surface changing its albedo and indirectly the surface temperature which changes the Yarkovsky effect. This study gives an in-depth description of both computational and experimental parts of the design of this system with primary focus on initial ground test setup. The initial experiments proposed to design the SATS is outlined in detail and justified by the mission criterion of interest as well as modeling the actual dispersal on the surface.
Link: Thesis (PDF)
Paper: Orbital dispersion and Earth-impact probability analysis for fragmented asteroids
A new paper from Lee, et al called "Orbital dispersion and Earth-impact probability analysis for fragmented asteroids".
PAPER REFERENCE:
Orbital dispersion and Earth-impact probability analysis for fragmented asteroids
Authors: Daero Lee(a), John E. Cochran Jr.(b), and Tas Soo No(c)
a. Wind Power Grid-Adaptive Technology Research Center, Chonbuk National University, Jeonju 560-756, Republic of Korea
b. Department of Aerospace Engineering, Auburn University, Auburn, AL 36849, USA
c. Department of Aerospace Engineering, Chonbuk National University, Jeonju 560-756, Republic of Korea
Received 10 November 2010; revised 21 March 2011; accepted 25 May 2011. Available online 1 June 2011.
Abstract:This paper describes the orbital dispersion problem for a fragmented asteroid in an elliptical orbit. The use of a state transition matrix derived from the general relative equation of motion for an elliptical orbit is emphasized in this paper. The state transition matrix is used to propagate the orbital dispersion. The Earth-impact probability is then computed to obtain a measure of the likelihood of impact with the Earth after the asteroid is fragmented with a high-energy fragmentation method. The state transition matrix approach is also compared with numerical integration approaches that use the two-body equation and the general relative equations of motion. The computational efficiency of such a state transition matrix approach is verified with accuracy equal to the numerical integration approaches. The employed state transition matrix, known as the Cochran, Lee and Jo (CLJ) state transition matrix, is also evaluated for the numerous fragments with data from the burst.
Link: Paper (Reference)
PAPER REFERENCE:
Orbital dispersion and Earth-impact probability analysis for fragmented asteroids
Authors: Daero Lee(a), John E. Cochran Jr.(b), and Tas Soo No(c)
a. Wind Power Grid-Adaptive Technology Research Center, Chonbuk National University, Jeonju 560-756, Republic of Korea
b. Department of Aerospace Engineering, Auburn University, Auburn, AL 36849, USA
c. Department of Aerospace Engineering, Chonbuk National University, Jeonju 560-756, Republic of Korea
Received 10 November 2010; revised 21 March 2011; accepted 25 May 2011. Available online 1 June 2011.
Abstract:This paper describes the orbital dispersion problem for a fragmented asteroid in an elliptical orbit. The use of a state transition matrix derived from the general relative equation of motion for an elliptical orbit is emphasized in this paper. The state transition matrix is used to propagate the orbital dispersion. The Earth-impact probability is then computed to obtain a measure of the likelihood of impact with the Earth after the asteroid is fragmented with a high-energy fragmentation method. The state transition matrix approach is also compared with numerical integration approaches that use the two-body equation and the general relative equations of motion. The computational efficiency of such a state transition matrix approach is verified with accuracy equal to the numerical integration approaches. The employed state transition matrix, known as the Cochran, Lee and Jo (CLJ) state transition matrix, is also evaluated for the numerous fragments with data from the burst.
Link: Paper (Reference)
Paper: Optimal impact strategies for asteroid deflection
A new paper from Vasile, et al called "Optimal impact strategies for asteroid deflection".
PAPER REFERENCE:
Optimal impact strategies for asteroid deflection
Authors: Massimiliano Vasile, Camilla Colombo (Submitted on 25 Apr 2011)
Abstract:This paper presents an analysis of optimal impact strategies to deflect potentially dangerous asteroids. To compute the increase in the minimum orbit intersection distance of the asteroid due to an impact with a spacecraft, simple analytical formulas are derived from proximal motion equations. The proposed analytical formulation allows for an analysis of the optimal direction of the deviating impulse transferred to the asteroid. This ideal optimal direction cannot be achieved for every asteroid at any time; therefore, an analysis of the optimal launch opportunities for deviating a number of selected asteroids was performed through the use of a global optimization procedure. The results in this paper demonstrate that the proximal motion formulation has very good accuracy in predicting the actual deviation and can be used with any deviation method because it has general validity. Furthermore, the characterization of optimal launch opportunities shows that a significant deviation can be obtained even with a small spacecraft.
Cite as: arXiv:1104.4670v1 [astro-ph.IM]
Link: Paper (PDF format)
PAPER REFERENCE:
Optimal impact strategies for asteroid deflection
Authors: Massimiliano Vasile, Camilla Colombo (Submitted on 25 Apr 2011)
Abstract:This paper presents an analysis of optimal impact strategies to deflect potentially dangerous asteroids. To compute the increase in the minimum orbit intersection distance of the asteroid due to an impact with a spacecraft, simple analytical formulas are derived from proximal motion equations. The proposed analytical formulation allows for an analysis of the optimal direction of the deviating impulse transferred to the asteroid. This ideal optimal direction cannot be achieved for every asteroid at any time; therefore, an analysis of the optimal launch opportunities for deviating a number of selected asteroids was performed through the use of a global optimization procedure. The results in this paper demonstrate that the proximal motion formulation has very good accuracy in predicting the actual deviation and can be used with any deviation method because it has general validity. Furthermore, the characterization of optimal launch opportunities shows that a significant deviation can be obtained even with a small spacecraft.
Cite as: arXiv:1104.4670v1 [astro-ph.IM]
Link: Paper (PDF format)
19 August 2011
Ed Lu at TEDxNASA@SiliconValley 2011 on asteroid detection
From ZDNet Smart Planet....At TEDxNASA in San Francisco, former astronaut and physicist Ed Lu discusses the need to develop an early-warning and precision tracking/guidance system to prevent asteroids from hitting the planet.
18 August 2011
Media Confusion on ESA Don Quijote Mission
A recent spate of news articles over the last 1-2 days needed some clarification regarding the ESA asteroid mission Don Quijote. I have noticed an inordinate amount of web articles on this mission yesterday and today (August 16-17), several years after it was analyzed as a potential mission concept study.
From some preliminary investigating it seems as if some of the articles/blogs that have carried this new item across the planet have indicated that the asteroid Apophis is a mission target (which it was not) and suggesting that the mission is more truly funded than it is (indicating a launch in 2015). One of the referenced articles is the London Daily Mail article. Another article is from Gizmodo and another article is from RedOrbit. These articles/posts seem to have been picked up and referenced by other news sources.
This FoxNews article attempts to correct the interpretation, the following comes from the article: "If an asteroid were ever detected, we'd want to do something -- and deflection is definitely one of the options," an ESA source told FoxNews.com. But despite a Daily Mail story touting the program as current, Don Quijote has long been shuttered. "The Don Quijote mission has been a study only. ESA is not working on this mission anymore," ESA spokesman Andreas Schepers told FoxNews.com.
My current perception is that this was a mission study that was never picked up by ESA for an actual mission (such as a NASA Discovery Class mission) since it was developed in a slightly different administrative area of ESA. UPDATE: The mission was initiated and performed by the ESA General Studies Programme in ESA's Future and Strategic Studies Office (with the technical support of the Concurrent Design Facility - CDF). The "missions" part of ESA did not pick up this concept study for an actual mission (my own estimate of ESA's organizational structure may be slightly off, but the general concept is probably correct). There may be attempts in the next 2-3 years to market this mission concept by ESA to its management within the EU but my opinion is that there is no actual funded mission as such as indicated in these articles (unfortunately for those with an interest in this area).
Generally, I think one would want to be very careful of any asteroid mitigation demonstration mission on the asteroid Apophis. That would probably be a test target of last resort. Given the uncertainty of effect of any impact mitigation mission, one would want to choose a relatively benign target (which Apophis is not given potential for disruption in its orbit during certain keyhole passes at a minimum). This comment is not mean to be any negative comment on any one specific news source but an attempt to clarify the general media record.
Here is some accurate information from the European Space Agency (ESA) on the mission: Don Quijote mission page.
Update: Video Report from Australia that also potentially adds confusion to the story in terms of the current status of the Don Quijote mission.
From some preliminary investigating it seems as if some of the articles/blogs that have carried this new item across the planet have indicated that the asteroid Apophis is a mission target (which it was not) and suggesting that the mission is more truly funded than it is (indicating a launch in 2015). One of the referenced articles is the London Daily Mail article. Another article is from Gizmodo and another article is from RedOrbit. These articles/posts seem to have been picked up and referenced by other news sources.
This FoxNews article attempts to correct the interpretation, the following comes from the article: "If an asteroid were ever detected, we'd want to do something -- and deflection is definitely one of the options," an ESA source told FoxNews.com. But despite a Daily Mail story touting the program as current, Don Quijote has long been shuttered. "The Don Quijote mission has been a study only. ESA is not working on this mission anymore," ESA spokesman Andreas Schepers told FoxNews.com.
My current perception is that this was a mission study that was never picked up by ESA for an actual mission (such as a NASA Discovery Class mission) since it was developed in a slightly different administrative area of ESA. UPDATE: The mission was initiated and performed by the ESA General Studies Programme in ESA's Future and Strategic Studies Office (with the technical support of the Concurrent Design Facility - CDF). The "missions" part of ESA did not pick up this concept study for an actual mission (my own estimate of ESA's organizational structure may be slightly off, but the general concept is probably correct). There may be attempts in the next 2-3 years to market this mission concept by ESA to its management within the EU but my opinion is that there is no actual funded mission as such as indicated in these articles (unfortunately for those with an interest in this area).
Generally, I think one would want to be very careful of any asteroid mitigation demonstration mission on the asteroid Apophis. That would probably be a test target of last resort. Given the uncertainty of effect of any impact mitigation mission, one would want to choose a relatively benign target (which Apophis is not given potential for disruption in its orbit during certain keyhole passes at a minimum). This comment is not mean to be any negative comment on any one specific news source but an attempt to clarify the general media record.
Here is some accurate information from the European Space Agency (ESA) on the mission: Don Quijote mission page.
Update: Video Report from Australia that also potentially adds confusion to the story in terms of the current status of the Don Quijote mission.
Paper: Measurement requirements for a near-Earth asteroid impact mitigation demonstration mission
From the MIT Technology Review article of a new paper from Wolters, et al called "Measurement requirements for a near-Earth asteroid impact mitigation demonstration mission"...
In 2002, the European Space Agency began a program called Don Quijote to find out how best to perform such a deflection. Don Quijote involves sending two spacecraft to a near Earth asteroid; one to smash into it and the other to watch while in orbit above the impact crater. The goal is to change the asteroid's semimajor axis by more than 100 metres and to measure the change with an accuracy greater than 1 per cent. But the question is how best to monitor what's going on in a way that is relevant to other asteroids. After all, the ultimate plan is to use the information from this mission to move some other asteroid with our name on it. Now, Stephen Wolters at the Open University in the UK and a few friends have published a new analysis of the mission saying that measuring the change in orbit is not enough. Instead, the spacecraft needs to characterise the impact in detail, determining the density of the material near the asteroid's surface, the size of the surface grains as well as the mass and speed distribution of the impact ejecta. Only with this information will it be possible to work out exactly how the momentum from the impactor was transferred to the asteroid. That significantly changes the mission. In addition to an on-board radio transmitter that will allow space scientists back on Earth to work out its distance exactly, the spacecraft will need a sophisticated imaging suite capable of photographing the damage and carrying out infrared spectroscopy to determine the asteroid's mineral content.
PAPER REFERENCE:
Measurement requirements for a near-Earth asteroid impact mitigation demonstration mission
Authors: Stephen D. Wolters, Andrew J. Ball, Nigel Wells, Christopher Saunders, Neil McBride (Submitted on 21 Jul 2011)
Abstract: A concept for an Impact Mitigation Preparation Mission, called Don Quijote, is to send two spacecraft to a Near-Earth Asteroid (NEA): an Orbiter and an Impactor. The Impactor collides with the asteroid while the Orbiter measures the resulting change in the asteroid's orbit, by means of a Radio Science Experiment (RSE) carried out before and after impact. Three parallel Phase A studies on Don Quijote were carried out for the European Space Agency: the research presented here reflects outcomes of the study by QinetiQ. We discuss the mission objectives with regards to the prioritisation of payload instruments, with emphasis on the interpretation of the impact. The Radio Science Experiment is described and it is examined how solar radiation pressure may increase the uncertainty in measuring the orbit of the target asteroid. It is determined that to measure the change in orbit accurately a thermal IR spectrometer is mandatory, to measure the Yarkovsky effect. The advantages of having a laser altimeter are discussed. The advantages of a dedicated wide-angle impact camera are discussed and the field-of-view is initially sized through a simple model of the impact.
Cite as: arXiv:1107.4229v1 [astro-ph.IM]
Link: MIT Technology Review Article
Link: Paper (PDF format)
Paper: Utilization of H-reversal Trajectory of Solar Sail for Asteroid Deflection
From the MIT Technology Review article of a new paper from Gong, et al called "Utilization of H-reversal Trajectory of Solar Sail for Asteroid Deflection"...
Apophis is a 46 million tonne asteroid that will pass within a hair's breath of Earth in 2029. However, Apophis's trajectory is likely to take it through a region of space near Earth known as a keyhole that will ensure the asteroid returns in 2036. Nobody knows how close Apophis will come on that pass. But if there's a chance of a collision, we'll have only 7 years to work out how to avoid catastrophe. Today, Shengping Gong and pals at Tsinghua University in Beijing say they've come up with a plan that will ensure Apophis never returns to Earth on this timescale . They point out that keyholes are tiny, in this case just 600 metres wide. So deflecting Apophis by only a small amount in the near future will ensure it misses the keyhole and so cannot return to Earth. There are various ways to deflect an asteroid. Gong and pals say their preference is to use a solar sail to place a small spacecraft into a retrograde orbit and on collision course with Apophis. The retrograde orbit will give it an impact velocity of 90km/s which, if they do this well enough in advance, should lead to a collision large enough to do the trick.
PAPER REFERENCE:
Utilization of H-reversal Trajectory of Solar Sail for Asteroid Deflection
Authors: Shengping Gong, Junfeng Li, Xiangyuan Zeng (Submitted on 16 Aug 2011)
Abstract: Near Earth Asteroids have a possibility of impacting with the Earth and always have a thread on the Earth. This paper proposes a way of changing the trajectory of the asteroid to avoid the impaction. Solar sail evolving in a H-reversal trajectory is utilized for asteroid deflection. Firstly, the dynamics of solar sail and the characteristics of the H-reversal trajectory are analyzed. Then, the attitude of the solar sail is optimized to guide the sail to impact with the object asteroid along a H-reversal trajectory. The impact velocity depends on two important parameters: the minimum solar distance along the trajectory and lightness number. A larger lightness number and a smaller solar distance lead to a higher impact velocity. Finally, the deflection capability of a solar sail impacting with the asteroid along the H-reversal is discussed. The results show that a 10 kg solar sail with a lead-time of one year can move Apophis out of a 600-m keyhole area in 2029 to eliminate the possibility of its resonant return in 2036.
Cite as: arXiv:1108.3183v1 [astro-ph.IM]
Link: MIT Technology Review Article
Link: Paper (PDF format)
Apophis is a 46 million tonne asteroid that will pass within a hair's breath of Earth in 2029. However, Apophis's trajectory is likely to take it through a region of space near Earth known as a keyhole that will ensure the asteroid returns in 2036. Nobody knows how close Apophis will come on that pass. But if there's a chance of a collision, we'll have only 7 years to work out how to avoid catastrophe. Today, Shengping Gong and pals at Tsinghua University in Beijing say they've come up with a plan that will ensure Apophis never returns to Earth on this timescale . They point out that keyholes are tiny, in this case just 600 metres wide. So deflecting Apophis by only a small amount in the near future will ensure it misses the keyhole and so cannot return to Earth. There are various ways to deflect an asteroid. Gong and pals say their preference is to use a solar sail to place a small spacecraft into a retrograde orbit and on collision course with Apophis. The retrograde orbit will give it an impact velocity of 90km/s which, if they do this well enough in advance, should lead to a collision large enough to do the trick.
PAPER REFERENCE:
Utilization of H-reversal Trajectory of Solar Sail for Asteroid Deflection
Authors: Shengping Gong, Junfeng Li, Xiangyuan Zeng (Submitted on 16 Aug 2011)
Abstract: Near Earth Asteroids have a possibility of impacting with the Earth and always have a thread on the Earth. This paper proposes a way of changing the trajectory of the asteroid to avoid the impaction. Solar sail evolving in a H-reversal trajectory is utilized for asteroid deflection. Firstly, the dynamics of solar sail and the characteristics of the H-reversal trajectory are analyzed. Then, the attitude of the solar sail is optimized to guide the sail to impact with the object asteroid along a H-reversal trajectory. The impact velocity depends on two important parameters: the minimum solar distance along the trajectory and lightness number. A larger lightness number and a smaller solar distance lead to a higher impact velocity. Finally, the deflection capability of a solar sail impacting with the asteroid along the H-reversal is discussed. The results show that a 10 kg solar sail with a lead-time of one year can move Apophis out of a 600-m keyhole area in 2029 to eliminate the possibility of its resonant return in 2036.
Cite as: arXiv:1108.3183v1 [astro-ph.IM]
Link: MIT Technology Review Article
Link: Paper (PDF format)
12 July 2011
Dr. Tom Gehrels (1925-2011): Planetary Scientist and Astronomer
News announcement from the University of Arizona. From the Lunar and Planetary Laboratory In Memoriam Page for Dr. Tom Gehrels...
Professor Tom Gehrels, 1925–2011
Professor Tom Gehrels joined the UA's Lunar and Planetary Laboratory (LPL) in 1961 as an Associate Professor. He earned his B.S. in Physics and Astronomy from Leiden (Netherlands) University in 1951, and his Ph.D. in Astronomy and Astrophysics from the University of Chicago in 1956.
While at Chicago, he worked with Subrahmanyan Chandrasekhar and Gerard P. Kuiper (who founded LPL in 1960). Dr. Gehrels' distinguished science career featured many highlights. During the 1950s, Professor Gehrels pioneered the first photometric system of asteroids and discovered the opposition effect in the brightness of asteroids. In the 1960s, he pioneered wavelength dependence of polarization of stars and planets. His research interests then migrated to imaging photopolarimetry of Jupiter and Saturn, and Dr. Gehrels was named principal investigator for the Pioneer 10 and 11 Imaging Photopolarimeters, which discovered Saturn's F ring.
In 1980, Tom Gehrels founded the Spacewatch Project, which uses telescopes on Kitt Peak to survey the sky for dangerous asteroids; he led the project until 1997. Professor Gehrels also founded the well known and well respected Space Science Series, still published by the University of Arizona Press. He served as general editor for the first 30 volumes of the series. At its start in the 1980s, the Space Science Series represented a new way of producing research textbooks. In 2007, Tom Gehrels was the recipient of the Harold Masursky Award, presented by the American Astronomical Society's Division for Planetary Sciences in recognition of meritorious service to planetary science.
Professor Gehrels' recent research interests were in universal evolution. Each fall, he taught an undergraduate course for non-science majors at the University of Arizona and each spring, he presented a brief version of that course at the Physical Research Laboratory in Ahmedabad, India, where he was a lifetime Fellow.
Link: University of Arizona News Announcement
Link: LPL In Memoriam Page (Tom Gehrels)
Link: Wikipedia (Tom Gehrels)
Link: PryS/LPL Faculty Page
Link: mpml annoucement
Professor Tom Gehrels, 1925–2011
Professor Tom Gehrels joined the UA's Lunar and Planetary Laboratory (LPL) in 1961 as an Associate Professor. He earned his B.S. in Physics and Astronomy from Leiden (Netherlands) University in 1951, and his Ph.D. in Astronomy and Astrophysics from the University of Chicago in 1956.
While at Chicago, he worked with Subrahmanyan Chandrasekhar and Gerard P. Kuiper (who founded LPL in 1960). Dr. Gehrels' distinguished science career featured many highlights. During the 1950s, Professor Gehrels pioneered the first photometric system of asteroids and discovered the opposition effect in the brightness of asteroids. In the 1960s, he pioneered wavelength dependence of polarization of stars and planets. His research interests then migrated to imaging photopolarimetry of Jupiter and Saturn, and Dr. Gehrels was named principal investigator for the Pioneer 10 and 11 Imaging Photopolarimeters, which discovered Saturn's F ring.
In 1980, Tom Gehrels founded the Spacewatch Project, which uses telescopes on Kitt Peak to survey the sky for dangerous asteroids; he led the project until 1997. Professor Gehrels also founded the well known and well respected Space Science Series, still published by the University of Arizona Press. He served as general editor for the first 30 volumes of the series. At its start in the 1980s, the Space Science Series represented a new way of producing research textbooks. In 2007, Tom Gehrels was the recipient of the Harold Masursky Award, presented by the American Astronomical Society's Division for Planetary Sciences in recognition of meritorious service to planetary science.
Professor Gehrels' recent research interests were in universal evolution. Each fall, he taught an undergraduate course for non-science majors at the University of Arizona and each spring, he presented a brief version of that course at the Physical Research Laboratory in Ahmedabad, India, where he was a lifetime Fellow.
Link: University of Arizona News Announcement
Link: LPL In Memoriam Page (Tom Gehrels)
Link: Wikipedia (Tom Gehrels)
Link: PryS/LPL Faculty Page
Link: mpml annoucement
17 May 2011
Article: Anders Sandberg on Progress in Mitigating Asteroid Impact Risks
Anders Sandberg, postdoctoral fellow at the Future of Humanity Institute of Oxford University, gave the keynote address at the May 9-12, 2011, Planetary Defense Conference in Bucharest, Romania sponsored by the International Academy of Astronautics. Here is his short microsummary of the event:
Link: Article ("Anders Sandberg on Progress in Mitigating Asteroid Impact Risks")
Microsummary: we are on the right track!
The latest estimates of the NEO size distribution by Alan W Harris retain the shape of previous estimates, a power law with a pretty steep exponent and an unexplained ‘dimple’ where there are too few 10-100 m NEOs.
Donald Yeomans showed that the impact flux from comets is small compared to Near Earth Asteroids (NEAs) (less than a percent). Satelite surveys have produced a flood of data (check out this animation or my graphs) and we have good reason to think we have already seen a sizeable fraction of the NEAs that would be serious global catastrophic risks (GCRs) - and they are in orbits that are safe for at least the next century. This has really reduced the expected risk.
The mandate from the US Congress wants a 90% completion by 2020 for the big (>140) NEAs, which might be tough unless there is some extra push (ideally a Venus orbit satelite or more time at the Large Synoptic Survey).
The LSS will be able to catch a lot of 45 m objects 1-3 months out, and people are starting to seriously look at finding smaller objects on their “death plunge” just before they hit Earth. They pose just local risk (if any at all) but as the GCR risk is retired their relative risk go up. Mark Boslough showed that some of them might produce pretty destructive airbursts. This domain also deals with the “we are going to be so successful that we are going to put ourselves out of business” problem - we are 10 times more likely to save lives by including imminent impactors in the next surveys, although the number of lives saved might be smallish.
Obama’s call for a manned NEO mission is a tough challenge, mainly because the best objects from a mission technical perspective (low deltav etc) might be smaller than the spaceship! Overall, NEO missions are maturing but the Japanese seem to be a decade ahead with Hayabusa and Hayabusa II.
Deflecting asteroids with kinetic impactors looks pretty good, but a lot hinges on the porosity of the asteroid. A fluffy asteroid just absorbs the impact, while a “hard” asteroid will eject a plume of debris that gives an extra push. Unfortunately we have no way of measuring the porosity, so plenty of talks investigated models and ways of estimating it.
Gravity tractors are wimpy, but seem to be fairly close to a realistic technology. They are pretty useless for deflecting an asteroid away from Earth, but enough for preventing it from going through a keyhole. This makes them a pretty ideal supplement for any mission. Flotillas of tractors can be more effective than single tractors. Paul W. Chodas also showed that there are “Jabbas”, robust states of an orbit that are hard to budge.
Nuclear deflection looks like it is workable, but it is definitely a last resort and mainly useful for imminent hits. Some serious issues about how to avoid dispersing loosely held together impactors. The main problem is getting the warheads to the impactor in time and to have them detonate at the right standoff distance.
Erick Ball described a real “Armageddon” scenario where a 5 km long periodic comet discovered ~290 days out could be deflected if mankind really got its act together - something we all felt was doubtful. Several other deflection methods (laser ablation, robotic rockthrowing, ion beam shepherds, painting to cause Yarkovsky effect deviations…) are investigated but not ready from prime time. Another problem is that NEOs seem to be quite different from each other, and methods that work for one type might need to be tweaked for other types.
Organisationally, things are moving forward. NEO study and defense is becoming more and more organised in the big space agencies, the UN and the US government. Some interesting notes from Frans von der Dunk on the legal aspects: check out the report “Legal Aspects of NEO Threat Response and Related Institutional Issues.”
In particular, the ‘responsibility to protect’ might apply here, requiring states to have capabilities to deal with NEO risks. There are also an interesting possible tradeoff between sharing information and doing missions in an open manner and avoiding liability: if damage occurs in the course of a NEO response states might not be held liable as long as the mission is within parameters set by proper mandate international community groups.
My own talk was about the issue of cognitive bias and rationality in impact mitigation. Basically, our biases are interfering with both the public, decisionmakers and the research community, and overcoming them is an important part in public relations, explaining the situation and doing the research. Not all of them are bad for the impact risk community: the preference for hard numbers really helps it in the “competition” with softer risks. But availability bias (it has never happened, never will) and scope neglect (a million dead are just
statistics) make many decisions rather irrational.
statistics) make many decisions rather irrational.
There are also problems with planetary defence being a public good, being long-term (it might be rational to put off doing things for a while, since tech is advancing - but this easily leads to putting off doing things too long; the “sweet spot” might be a decade, about a political lifetime) and discounting the future too heavily.
However, I think the impact community are an example to all of us dealing with other existential risks. They are doing a pretty good job. They have managed to 1) demonstrate the existence of a risk and quantify it, 2) convinced enough decisionmakers to fund preliminary investigation, 3) built a lively interdisciplinary community devoted to the risk and mitigation (with an inflow of new students carrying on and developing the thinking). Other risk communities may do well to study how they did it.
And finally, a great motto: “There ain’t no such thing as a free launch.”
Link: Article ("Anders Sandberg on Progress in Mitigating Asteroid Impact Risks")
16 May 2011
Paper: "New applications of the H-reversal trajectory using solar sails"
New applications of the H-reversal trajectory using solar sails
Xiangyuan Zeng, Hexi Baoyin, Junfeng Li, Shengping Gong
(Submitted on 8 Mar 2011)
Abstract:
Advanced solar sailing has been an increasingly attractive propulsion system for highly non-Keplerian orbits. Three new applications of the orbital angular momentum reversal (H-reversal) trajectories using solar sails are presented in this paper: space observation, heliocentric orbit transfer, and collision orbits with asteroids. A theoretical proof for the existence of double H-reversal trajectories (referred to as 'H2RTs') is given, and the characteristics of the H2RTs are introduced before the discussion of the mission applications. A new family of H2RTs was obtained using a 3D dynamic model of the two-body frame. In a time-optimal control model, the minimum period H2RTs both inside and outside the ecliptic plane were examined using an ideal solar sail. Due to the quasi-heliostationary property at its two symmetrical aphelia, the H2RTs were deemed suitable for space observation. For the second application, the heliocentric transfer orbit was able to function as the time-optimal H-reversal trajectory, as its perihelion velocity is circular or elliptic velocity. Such a transfer orbit can place the sailcraft into a clockwise orbit in the ecliptic plane, with a high inclination or displacement above or below the Sun. The third application of the H-reversal trajectory was simulated impacting an asteroid passing near Earth in a head-on collision. The collision point can be designed through selecting different perihelia or different launch windows. Sample orbits of each application were presented through numerical simulation. The results can serve as a reference for theoretical research and engineering design.
Link: Paper reference
Link: Paper [PDF}
Xiangyuan Zeng, Hexi Baoyin, Junfeng Li, Shengping Gong
(Submitted on 8 Mar 2011)
Abstract:
Advanced solar sailing has been an increasingly attractive propulsion system for highly non-Keplerian orbits. Three new applications of the orbital angular momentum reversal (H-reversal) trajectories using solar sails are presented in this paper: space observation, heliocentric orbit transfer, and collision orbits with asteroids. A theoretical proof for the existence of double H-reversal trajectories (referred to as 'H2RTs') is given, and the characteristics of the H2RTs are introduced before the discussion of the mission applications. A new family of H2RTs was obtained using a 3D dynamic model of the two-body frame. In a time-optimal control model, the minimum period H2RTs both inside and outside the ecliptic plane were examined using an ideal solar sail. Due to the quasi-heliostationary property at its two symmetrical aphelia, the H2RTs were deemed suitable for space observation. For the second application, the heliocentric transfer orbit was able to function as the time-optimal H-reversal trajectory, as its perihelion velocity is circular or elliptic velocity. Such a transfer orbit can place the sailcraft into a clockwise orbit in the ecliptic plane, with a high inclination or displacement above or below the Sun. The third application of the H-reversal trajectory was simulated impacting an asteroid passing near Earth in a head-on collision. The collision point can be designed through selecting different perihelia or different launch windows. Sample orbits of each application were presented through numerical simulation. The results can serve as a reference for theoretical research and engineering design.
Link: Paper reference
Link: Paper [PDF}
Paper: "Planetary Defense and an Energy Infrastructure for Near Earth Space"
Planetary Defense and an Energy Infrastructure for Near Earth Space
Fork, R.; Burgess, L.; Bergstue, G.; Gaillard, R.; Dept. of Electr./Comput. Eng., Univ. of Alabama Huntsville, Huntsville, AL, USA
Proceedings of the IEEE
Issue Date: March 2011
Volume: 99 Issue:3
On page(s): 359 - 362
ISSN: 0018-9219
INSPEC Accession Number: 11821910
Digital Object Identifier: 10.1109/JPROC.2010.2096250
Date of Current Version: 17 February 2011
Sponsored by: IEEE
Abstract:
The White House Office of Science and Technology (OSTP), in response to recent Congressional action, assigned National Aeronautics and Space Administration (NASA) the task of: "(A) protecting the United States from a near-Earth object that is expected to collide with Earth; and (B) implementing a deflection Digital Object campaign. A "functional analysis" of the task was recommended. A planetary defense strategy was considered to such an analysis. Using lasers in space for planetary defense and space energy infrastructure will reduce the current cost of lift to orbit, remove debris from space, assist in rescuing astronauts in difficulty, and deliver energy to other resources in space, and possibly, even eventually to Earth.
Link: IEEE XPlore
Fork, R.; Burgess, L.; Bergstue, G.; Gaillard, R.; Dept. of Electr./Comput. Eng., Univ. of Alabama Huntsville, Huntsville, AL, USA
Proceedings of the IEEE
Issue Date: March 2011
Volume: 99 Issue:3
On page(s): 359 - 362
ISSN: 0018-9219
INSPEC Accession Number: 11821910
Digital Object Identifier: 10.1109/JPROC.2010.2096250
Date of Current Version: 17 February 2011
Sponsored by: IEEE
Abstract:
The White House Office of Science and Technology (OSTP), in response to recent Congressional action, assigned National Aeronautics and Space Administration (NASA) the task of: "(A) protecting the United States from a near-Earth object that is expected to collide with Earth; and (B) implementing a deflection Digital Object campaign. A "functional analysis" of the task was recommended. A planetary defense strategy was considered to such an analysis. Using lasers in space for planetary defense and space energy infrastructure will reduce the current cost of lift to orbit, remove debris from space, assist in rescuing astronauts in difficulty, and deliver energy to other resources in space, and possibly, even eventually to Earth.
Link: IEEE XPlore
SGAC Future of Planetary Defense Video Clips
The Space Generation Advisory Council (SGAC) hosted a one day public event on the Future of Planetary Defense, prior to the start of the 2nd IAA Planetary Defense conference. These are selected videos from the event.
Link: YouTube Video ("Future of Planetary Defense News Broadcast.AVI")
Link: YouTube Video ("Rusty-about-Dorin_480p.wmv")
Link: YouTube Video ("Future of Planetary Defense News Broadcast.AVI")
Link: YouTube Video ("Rusty-about-Dorin_480p.wmv")
Posts from Bruce Betts at The Planetary Society on 2nd IAA Planetary Defense Conference
Bruce Betts from The Planetary Society had two blog posts summarizing some days at the 2011 IAA Planetary Defense Conference:
Bruce Betts reports from the Planetary Defense Conference in Romania
May. 9, 2011 | 15:00 PDT | 22:00 UTC
Day 2: Planetary Defense conference in Bucharest, Romania
May. 10, 2011 | 15:59 PDT | 22:59 UTC
Bruce Betts reports from the Planetary Defense Conference in Romania
May. 9, 2011 | 15:00 PDT | 22:00 UTC
Day 2: Planetary Defense conference in Bucharest, Romania
May. 10, 2011 | 15:59 PDT | 22:59 UTC
Annoucement: 2013 IAA Planetary Defense Conference in Flagstaff, Arizona USA (April 15-19, 2013)
The 2013 International Academy of Astronautics (IAA) Planetary Defense Conference will be held from April 15-19, 2013 in Flagstaff, Arizona USA. This announcement was made at the 2011 IAA Planetary Defense Conference. The 2013 conference will be organized by the NASA NEO office with potential assistance from several academic institutions in Arizona. Flagstaff is close to Barringer Crater.
12 May 2011
2011 IAA Planetary Defense Conference: Day 4 Session 8
Notes from Day 4 of 2011 IAA Planetary Defense Conference. Follow twitter feed for more information:
Day 4 (Thursday 12 May 2011) Session 8
Legal, Policy, POlitical Framework for Planetary Defense
- A'Hearn
"Recommendations of the US NRC Study on NEOs"
asked by US Congress a few years ago about NEO Surveys and NEO Hazard Mitigation
released Jan. 2010, reviewed 2006 NASA report
>-8 members from study at 2011 IAA PDC
different types of personnel (nukes, anti-nukes, robotic/astronaut enthusiasts)
independent costs estimates obtained but not in time (including in written report)
1. Cannot meet congressional mandate by 2020 (written in 2009), 90% of d>140m requires new technology
2. Venue trailing orbit can be done by 2022 if funding is available ($2-3B including 7 years of operations) - NRC Ah Hoc comm advocated in-space obs.
3. probably IR but maybe in optical
4. LSST could be it by 2025, by 2030, or sonner in NEO-optimized shared mods
Survey try to find smaller object less than 140m (30-50m diameter) if font interfere with >140m objects, do not stop once you have found <140 m objects
Arecibo radar important
4 approaches to mitigation: civil defense, slow push (tug, solar heating, albdeo change, GT), kinetic impact, nuclear blast
boundary between technique is fuzzy
Q: NRC report misunderstands role of gravity tractor, Rusty: not a deflection for an Earth impact, mission for keyhole impact (necessary for every mission) - needed for all missions, keyhole deflector not an earth deflector
Q: break connection of disruption with last minute defense
- Sergio Comacho
"Progress of NEO Activities within the UN COPUOS"
talks about Action Team 14 (on NEOs) and UN CONPUOS
Report by ASE's international panel on asteroid threat mitigation
finished 30 Sept. 2008m Nov. 2008 summary presented by AT-14
NEOs preocess under a work plan - 2009 until 2011 (work carried out by STSC(and its WG) and CONPUOS, internsessionally bt AT-14
Workshop on a NEO mission planning and operations group (MPOG) at ESA's ESOC in Darmstadt in Oct. 2010
Interim report, L.308, contains an annex to the revised " Draft Recommendation for international response to the Near Earth Object Impact Threat"
AT-14 (27 members) and WG reviewed L.308 and those updates were incorporated in the interim report of AT-14 (2011-2012)
Multi-year work plan on NEOs has been extended for two more years (2012-2013)
Intersessional work in 2011-2012 could include workshops of experts on various aspects of draft recommendations made by Action Team
Intersessional work on 2011-2012 to talk about MPOG
- Boris Shustov
"National NEO Program Plans" [in Russia]
Space Council for Russian Academy of Sciences include group looking at space debris and NEOs
Two major bodies include Russian Federal Agency (Yuri Makarov) and Russian Academy of Sciences (Ministry, 230 institutions)
Space Council of Russian Academy of Sciences
Activity on NEO problem in Russia is rising
Book on NEOs, published in Russia in 2010 (written in two levels)
Need a comprehensive (federal) program in Russia on international cooperation on NEOs
draft concept of long etmer federal NEO program group prepared by Expert Working Group on ACH by the Space Council of the RAS
June 2010, special joint meeting of the heads of Federal Space Agency and RAS was held
Roscomos and RAS want to integrate NEOs and space debris, preliminary name: "System of Mitigation of Space Threats", program under preparation, complex program (detail) presented in fall of 2011
items:
- new optical instruments for massive discovery
- wide-angle 1.6 m telescope (400-1100 nm) AZT-33VM
- space born telescope for NEOs
- includes follow-up observatories
- radar technology for NEos (Ukraine and Russian): 70m radar in Ussuriisk for study of PHO
- Space mission, pre phase A study of automated mission is completed, Phase A will be completed in 2012, study physical properties of PHA (maybe Apophis)
- put a radio beacon on asteroid (depends on Phobos-Grunt mission scheduled for launch in Nov. 2011)
Lockne meteorite crater: formed 450m years ago by impact of 600 meters
Tunguska investigation included in program
- Lindley Johnson
NASA HQ
references OSTP letter dates 15 oct. 2010 (response to NASA Authorization Act)
Damon Wells from OSTP coordinated from presentation
US National Policy in June 28, 2010 document: first time NASA policy specifies NEO threat action, first time in such a document at such a level, provided leverage for NASA to work with other agencies
plus up from NEO program from $5M program to $20.4M program
new plans for NEO human missions by 2025
NEO threat detection:
NASA will coordinate NEO detection and threat information, NASA would include direction of public information, NASA has set up information process for threats
upon notification from NASA:
1. threat to US territory, FEMA takes lead (FEMA can only advise on evacuation)
2. beyond US territory, US Department of State facilities efforts
homework needs to be done from WH perspective on potential NEO mitigation/deflection as to maturity of who to assign it to? (NASA-unclear)
Q: in terms of mitigation, who is leading within NASA
A: see the OCT put it in one of their calls, needs still to be organized: what is the outcome of the PD task force: has not been decided by the administrator: hope can announce at LPSC next year, perhaps not under one directorate, opportunities under Science and Space Exploration, and maybe technologist, may need to be a PLD coordination office to keep a focus on the activity
Day 4 (Thursday 12 May 2011) Session 8
Legal, Policy, POlitical Framework for Planetary Defense
- A'Hearn
"Recommendations of the US NRC Study on NEOs"
asked by US Congress a few years ago about NEO Surveys and NEO Hazard Mitigation
released Jan. 2010, reviewed 2006 NASA report
>-8 members from study at 2011 IAA PDC
different types of personnel (nukes, anti-nukes, robotic/astronaut enthusiasts)
independent costs estimates obtained but not in time (including in written report)
1. Cannot meet congressional mandate by 2020 (written in 2009), 90% of d>140m requires new technology
2. Venue trailing orbit can be done by 2022 if funding is available ($2-3B including 7 years of operations) - NRC Ah Hoc comm advocated in-space obs.
3. probably IR but maybe in optical
4. LSST could be it by 2025, by 2030, or sonner in NEO-optimized shared mods
Survey try to find smaller object less than 140m (30-50m diameter) if font interfere with >140m objects, do not stop once you have found <140 m objects
Arecibo radar important
4 approaches to mitigation: civil defense, slow push (tug, solar heating, albdeo change, GT), kinetic impact, nuclear blast
boundary between technique is fuzzy
Q: NRC report misunderstands role of gravity tractor, Rusty: not a deflection for an Earth impact, mission for keyhole impact (necessary for every mission) - needed for all missions, keyhole deflector not an earth deflector
Q: break connection of disruption with last minute defense
- Sergio Comacho
"Progress of NEO Activities within the UN COPUOS"
talks about Action Team 14 (on NEOs) and UN CONPUOS
Report by ASE's international panel on asteroid threat mitigation
finished 30 Sept. 2008m Nov. 2008 summary presented by AT-14
NEOs preocess under a work plan - 2009 until 2011 (work carried out by STSC(and its WG) and CONPUOS, internsessionally bt AT-14
Workshop on a NEO mission planning and operations group (MPOG) at ESA's ESOC in Darmstadt in Oct. 2010
Interim report, L.308, contains an annex to the revised " Draft Recommendation for international response to the Near Earth Object Impact Threat"
AT-14 (27 members) and WG reviewed L.308 and those updates were incorporated in the interim report of AT-14 (2011-2012)
Multi-year work plan on NEOs has been extended for two more years (2012-2013)
Intersessional work in 2011-2012 could include workshops of experts on various aspects of draft recommendations made by Action Team
Intersessional work on 2011-2012 to talk about MPOG
- Boris Shustov
"National NEO Program Plans" [in Russia]
Space Council for Russian Academy of Sciences include group looking at space debris and NEOs
Two major bodies include Russian Federal Agency (Yuri Makarov) and Russian Academy of Sciences (Ministry, 230 institutions)
Space Council of Russian Academy of Sciences
Activity on NEO problem in Russia is rising
Book on NEOs, published in Russia in 2010 (written in two levels)
Need a comprehensive (federal) program in Russia on international cooperation on NEOs
draft concept of long etmer federal NEO program group prepared by Expert Working Group on ACH by the Space Council of the RAS
June 2010, special joint meeting of the heads of Federal Space Agency and RAS was held
Roscomos and RAS want to integrate NEOs and space debris, preliminary name: "System of Mitigation of Space Threats", program under preparation, complex program (detail) presented in fall of 2011
items:
- new optical instruments for massive discovery
- wide-angle 1.6 m telescope (400-1100 nm) AZT-33VM
- space born telescope for NEOs
- includes follow-up observatories
- radar technology for NEos (Ukraine and Russian): 70m radar in Ussuriisk for study of PHO
- Space mission, pre phase A study of automated mission is completed, Phase A will be completed in 2012, study physical properties of PHA (maybe Apophis)
- put a radio beacon on asteroid (depends on Phobos-Grunt mission scheduled for launch in Nov. 2011)
Lockne meteorite crater: formed 450m years ago by impact of 600 meters
Tunguska investigation included in program
- Lindley Johnson
NASA HQ
references OSTP letter dates 15 oct. 2010 (response to NASA Authorization Act)
Damon Wells from OSTP coordinated from presentation
US National Policy in June 28, 2010 document: first time NASA policy specifies NEO threat action, first time in such a document at such a level, provided leverage for NASA to work with other agencies
plus up from NEO program from $5M program to $20.4M program
new plans for NEO human missions by 2025
NEO threat detection:
NASA will coordinate NEO detection and threat information, NASA would include direction of public information, NASA has set up information process for threats
upon notification from NASA:
1. threat to US territory, FEMA takes lead (FEMA can only advise on evacuation)
2. beyond US territory, US Department of State facilities efforts
homework needs to be done from WH perspective on potential NEO mitigation/deflection as to maturity of who to assign it to? (NASA-unclear)
Q: in terms of mitigation, who is leading within NASA
A: see the OCT put it in one of their calls, needs still to be organized: what is the outcome of the PD task force: has not been decided by the administrator: hope can announce at LPSC next year, perhaps not under one directorate, opportunities under Science and Space Exploration, and maybe technologist, may need to be a PLD coordination office to keep a focus on the activity
News Article: NASA's Dawn Captures First Image of Nearing Asteroid [Vesta]
Image obtained by NASA's Dawn spacecraft of the giant asteroid Vesta in front of a background of stars. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
This image, processed to show the true size of the giant asteroid Vesta, shows Vesta in front of a spectacular background of stars. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
From the article...
NASA's Dawn spacecraft has obtained its first image of the giant asteroid Vesta, which will help fine-tune navigation during its approach. Dawn is expected to achieve orbit around Vesta on July 16, when the asteroid is about 188 million kilometers (117 million miles) from Earth.
Link: News Release
2011 IAA Planetary Defense Conference: Day 4 Session 7
Notes from Day 4 of 2011 IAA Planetary Defense Conference. Follow twitter feed for more information:
Day 4 (Thursday 12 May 2011) Session 7
Student Session
- Charlotte Norlund
"NEOMiss: A New Earth Object Devision Support Tool"
Looking down at Earth, tool for investigation human vulnerability, uses the physical simulator used in NEOimpactor and NEOSim, previous work by Nick Bailey
includes uncertainties in model and data, uses a Monte Carlo approach, vulnerability models made for five land impact hazards, multi-hazard simulator, only looking at land impact and not water impact, behavior-based evacuation models base don US hurricane model
uses global gridded data (1x1km grid)
transportation: car, moped, walking options
National infrastructure: uses OpenStreetMap data (source of infrastructure data) and created gridded road network capacity and flow times
San Jose, CR evacuation simulation: evacuating an area north of San Jose is a challenge: 3.5 days is not enough (15% manage to evacuate)
An average of 2% of population in the affected area will be causalities along the Apophis risk corridor
Q: issues of different roads
Q: issue of different human perception
Q: issue of temporary or permanent evacuation
- Farnocchia, Davide
"The performances of A wide survey on a population of impactors"
deep survey: large objects >140m and large distance (0.5-1AU) for large warning time
wide survey: small objects < 140m, visible during close approach, wide field of view
Wide survey is a possible European asset (limited superposition with US surveys, significant NEO discovery rate)
survey stations: 4 survey stations (limiting mag from 23 and 21.5)
tracklet: set of observations in a short time span, need at least three tracklets for orbit
Q: issue on ecliptic region and looking for impactors there.
Day 4 (Thursday 12 May 2011) Session 7
Student Session
- Charlotte Norlund
"NEOMiss: A New Earth Object Devision Support Tool"
Looking down at Earth, tool for investigation human vulnerability, uses the physical simulator used in NEOimpactor and NEOSim, previous work by Nick Bailey
includes uncertainties in model and data, uses a Monte Carlo approach, vulnerability models made for five land impact hazards, multi-hazard simulator, only looking at land impact and not water impact, behavior-based evacuation models base don US hurricane model
uses global gridded data (1x1km grid)
transportation: car, moped, walking options
National infrastructure: uses OpenStreetMap data (source of infrastructure data) and created gridded road network capacity and flow times
San Jose, CR evacuation simulation: evacuating an area north of San Jose is a challenge: 3.5 days is not enough (15% manage to evacuate)
An average of 2% of population in the affected area will be causalities along the Apophis risk corridor
Q: issues of different roads
Q: issue of different human perception
Q: issue of temporary or permanent evacuation
- Farnocchia, Davide
"The performances of A wide survey on a population of impactors"
deep survey: large objects >140m and large distance (0.5-1AU) for large warning time
wide survey: small objects < 140m, visible during close approach, wide field of view
Wide survey is a possible European asset (limited superposition with US surveys, significant NEO discovery rate)
survey stations: 4 survey stations (limiting mag from 23 and 21.5)
tracklet: set of observations in a short time span, need at least three tracklets for orbit
Q: issue on ecliptic region and looking for impactors there.
11 May 2011
2011 IAA Planetary Defense Conference: Day 3 Session 6
Notes from Day 3 of 2011 IAA Planetary Defense Conference. Follow twitter feed for more information:
Day 3 (Wednesday 11 May 2011) Session 6
Mission Planning and Technologies
- Housen, K.
"Measuring the Momentum Transfer for Asteroid Deflection"
crater profile does not depend too much on void spaces
impact disruption of spinning bodies
rapid rotators will be more susceptible to disruption in a deflection mission
Beta for sand at 2km/s is 2, 10-20km/s for beta=3
beta may depend strongly on porosity
- Golubov
Influence of intermediate scale structure on Yarkovsky and YORP effects
YORP first pointed out by Rubincam
Asteroid Itokawa doe not demonstrate YORP model
- Andrew Klesh
Improved Navigation Techniques for Asteroid Landers and Impactors
based on JAXA work, Hayabusa 2 work
landed accuracy: NEAR (several hundred meters), Hayabusa, Marco Polo (3.5 n), H2 (several tens of meters)
Tracking features may not be an option
navigation by radio ranging
- Bombardelli, C.
"Ion Beam Shephred: A New Concept for Asteroid Deflection"
Ion Beam Shepherd (IBS)
primary ion engine pointed at asteroid surface, secondary propulsion to avoid IBS from drifting away from asteroid
currently under study by ESA and TU Madrid for space debris removal applications
beam divergence: need to make sure beam does not expand too much
for example. taking SOA thrusters, get 5-15 degrees and March of 20-30, handle 150 m diameter asteroid from a distance of 200m or less from center (50 m from surface)
force transmitted: penetrate asteroid surface a few nanometers, backsputtering is low
can beam pressure damage asteroid: local beam mechanical pressure: for example for 100m diameter asteroid, a 10N beam gives a peak pressure of less than 6mPa
for one year of thrusting have a Isp - 9000s
with Isp = 3k seconds
for asteroid below 500m gravity force is low
slow push asteroid deflection performance,
case: 2007 VK184 (D=130m)
1 N thrust for 2 years = 5 MT IBS (3000 sec Isp)
Gravity tractor needs more mass for same effect as IBS (50 MT needed for 150 m asteroid)
- Hayabusa2 Mission (Yoshikawa) - presented by alternative
has become project (Phase B)
budgetary request for H2 project was approved, on May 1, 2011 status of project becomes Phase B and under PDR (Preliminary Design Review)
C-type (1999 JU3) target now
0.922 km , around 1km in size (not irregular)
Spectrum is different
Launch of July 2014, arrival in June 2018, 3 samplings (sample, crater, and 2 samplings), reath return in 2019/2020,
500 m altitude release, canister will explode with projectile release, spacecraft will fly over crater and take sample)
small lander (MASCOT - under discussion): DLR/CNES MASCOT (10 kg lander) Mobile Asteroid Surface Scout
NASA: similar as H1
international collaboration may be possible
Day 3 (Wednesday 11 May 2011) Session 6
Mission Planning and Technologies
- Housen, K.
"Measuring the Momentum Transfer for Asteroid Deflection"
crater profile does not depend too much on void spaces
impact disruption of spinning bodies
rapid rotators will be more susceptible to disruption in a deflection mission
Beta for sand at 2km/s is 2, 10-20km/s for beta=3
beta may depend strongly on porosity
- Golubov
Influence of intermediate scale structure on Yarkovsky and YORP effects
YORP first pointed out by Rubincam
Asteroid Itokawa doe not demonstrate YORP model
- Andrew Klesh
Improved Navigation Techniques for Asteroid Landers and Impactors
based on JAXA work, Hayabusa 2 work
landed accuracy: NEAR (several hundred meters), Hayabusa, Marco Polo (3.5 n), H2 (several tens of meters)
Tracking features may not be an option
navigation by radio ranging
- Bombardelli, C.
"Ion Beam Shephred: A New Concept for Asteroid Deflection"
Ion Beam Shepherd (IBS)
primary ion engine pointed at asteroid surface, secondary propulsion to avoid IBS from drifting away from asteroid
currently under study by ESA and TU Madrid for space debris removal applications
beam divergence: need to make sure beam does not expand too much
for example. taking SOA thrusters, get 5-15 degrees and March of 20-30, handle 150 m diameter asteroid from a distance of 200m or less from center (50 m from surface)
force transmitted: penetrate asteroid surface a few nanometers, backsputtering is low
can beam pressure damage asteroid: local beam mechanical pressure: for example for 100m diameter asteroid, a 10N beam gives a peak pressure of less than 6mPa
for one year of thrusting have a Isp - 9000s
with Isp = 3k seconds
for asteroid below 500m gravity force is low
slow push asteroid deflection performance,
case: 2007 VK184 (D=130m)
1 N thrust for 2 years = 5 MT IBS (3000 sec Isp)
Gravity tractor needs more mass for same effect as IBS (50 MT needed for 150 m asteroid)
- Hayabusa2 Mission (Yoshikawa) - presented by alternative
has become project (Phase B)
budgetary request for H2 project was approved, on May 1, 2011 status of project becomes Phase B and under PDR (Preliminary Design Review)
C-type (1999 JU3) target now
0.922 km , around 1km in size (not irregular)
Spectrum is different
Launch of July 2014, arrival in June 2018, 3 samplings (sample, crater, and 2 samplings), reath return in 2019/2020,
500 m altitude release, canister will explode with projectile release, spacecraft will fly over crater and take sample)
small lander (MASCOT - under discussion): DLR/CNES MASCOT (10 kg lander) Mobile Asteroid Surface Scout
NASA: similar as H1
international collaboration may be possible
Canadian NEOSSat at 2011 IAA Planetary Defense Conference
Canadian NEOSSat (Near Earth Object Surveillance Satellite) at 2011 IAA planetary defense conference
Fully funded PhD in asteroid deflection research at Univ of Surrey in UK
Fully funded PhD in asteroid deflection research at Univ of Surrey in UK
2011 IAA Planetary Defense Conference: Day 3 Session 5
Notes from Day 3 of 2011 IAA Planetary Defense Conference. Follow twitter feed for more information:
Day 3 (Wednesday 11 May 2011) Session 5
Campaign Planning
- J-T Grundman
AsteroidSQAUDS/iSSB - Synergistic NEO Deflection Campaign and Mitigation Effects Test Mission
DLR
reflection of past IAA 2009 conference white paper: campaign studies and focus on smaller objects
looking at desires of various missions: heavy launcher development, fast mission scenarios, low space debris generation, include amateurs,
small and smart interceptor design produced in advance of heavy launch vehicle development
launcher test schedule triggers search for suitable target (3-6 months to launch)
every month 8-20 known NEOs approach Earth within 0.2 AU
NEAs about the size of 100m chosen
instruments: ranger like camera bank, dust counters, plasma instruments
take the AsteroidFinder spacecraft
have a more modular approach to spacecraft development
using CEF (Concurrent Engineering Facility)
put a kit together
interceptor: 179 kg mass
fits in standard secondary payload volume
took a Ariane 5 model for heavy life (12 MT to GTO)
20 impactors on a launch vehicle
Use Shoemaker Levi 9 multiple impact scenario
Q: need for observer spacecraft for any deflection
A: not about a proper deflection (testing mission) - not a deflection
- A. Zimmer
"Target Selection and Mission Analysis of Human Exploration Missions to NEAs"
Univ. of Stuttgart
complex trade space, multiple NEAs too many filers, launch window investigation, mission abort options
better understanding of parameter space for trajectory options for human missions
accessibility model: pre-selection of asteroid, based on celestial mechanics rather than scientific gain
approach: based on upper stage performance, departure from LEO, two impulse round trip mission, termination condition: deltaV limit (first burn) <10k/s, mission duration <365 days
verification of model: used 7812 NEAs, size criterion (H<=25) and slow rotation rate, 6704 NEAS, then semi-major axis, eccentricity, inclination: 2567 NEAs, then termination condition:
left with 240 NEAs between 2010 and 2040
statisitics: most attractive tragets with deltaV<7.5 km/s left with 73 targets - most of PHAs, pre-dominantly Atens and Apollos, many targets require long missions and high DeltaV
absolute mag less than 22-only about 20 NEOs
170 launch windows between 2020 and 2040
gradually increase in mission duration and then increase time with 1 mission every 2 years
looking at anytime abort (duration of return to Earth minimized) and free return (delta V minimized)
only investigated outbound mission leg only (once at asteroid)
long missions (= 365 day return, free return possible, anytime abort is limited)
better understand of abort options and assessment of prx ops, and Near Earth Largrnage points
design a building block of architecture
- Sugimoto, Y.
"Effects of NEO Composition on Deflection Methodologies"
Univ. of Glasgow
Looking at short warning time cases
for small bodies mass is not always available and estimate from bulk density if highly unlikely
most abundant NEOs are S-type asteroids (about 50%)
evidence theory can quantify epistemic uncertainties without assuming a distribution function specific to asteroid composition
NEO properties: micro-density, micro-porosity, bulk porosity, and albedo (out dist. on those)
two measures of uncertainty: beliefs and plausibility
set scene, set a baseline composition: 40% bulk porosity and 3.6g/cm?^2, and 0m2 albedo
deviation required (1.66 Earth-radii and 2.5 Earth-radii safe distance)
three types of mitigation missions: kinetic, nuclear, and solar collector
Q: did listing of meteorite densities did it include all data: did not include data, only a fraction of data are usable since meteorites have been weathered and potential better samples needed that are less weathered and handled better
Q: what is important is physical properties
- Cyrus Foster
"Multiple Concepts and Operations for Asteroid Mitigation including Multiple Gravity Tractors"
Deflection campaigns uses more than gravity tractor
redundant gravity tractor for insurance against failure
how does deflection scale with use of multiple gravity tractors
three concepts: single gravity tractors at a time, simultaneously tractor GTs w/station keeping, simultaneously tracting with mechanical docking to form single gravity tractor
used Apophis
looking at six launch opportunities: sending single 1MT gravity tractor
Concept 1: single GT at a time
other GTs an acts are tracking and use as backup
simpler operational concept but poorer deflection, total deflection of 76.1 km
Concept 2: simultaneous GTs
station keep around single point (could also be interested in halo orbits)
enables simultaneous ops but
total deflection of 122.4 km
Concept 3: mechanical docking approach
eliminates strict station keeping requirements but requires mechanical interface and docking ops
Concept 3b: keep empty gravity tractor docked
total deflection of 134.6 km
for Apophis: docked stacking provided a 10% improvement,
Trajectory Browser Tool at NASA Ames (web based tool to search rendezvous opportunities)
transfer from Earth to 8k NEOs and user can access database and select constraints
database of 2 body ballistic trajectories for various missions configurations
Mission Design Center Small Body Missions at NASA Ames
currently a NASA internal website
Q: perhaps increase efficiency for concept 1 if one if to use expended GT is sent
Q: use kinetic impactor and GT to trim perhaps, that might be easier
A: for Apophis multiple gravity tractor is overkill for this example (just providing it for example)
Q: how robust is the scenario are, launching GT at different times, putting GT later
Q: Looked at refueling GTs
A: Have not considered
Q: is the NEO tool distinguish types of NEOs based upon quality of observations
A: Yes, have orbit condition code as user input
- Nahum Melamed
"Development of Handbook and an online tool on Defending Earth against potentially hazardous objects"
develop a handbook for kinetic impact
develop a web based resource center for first order deflection mission requirements
aid in KI design
outreach
characterize NEO, determine deflection maneuver by using Lambert solution, select launch vehicle, determine deltaV, determine B Plan position
currently development B plane position is finished, working on the determine the trajectory phase portion
available on JPL portal at future stage
Current state of the web tool (Phase 1a)
ongoing development, save and retrieve buttons, B-plan updates, add variable resolution on earth impacts, possibly to vary to DeltaV slides, show keyholes,
Phase 1b development:
integrate with launch capability and use LV payload planners guide, use Lambert solution to connect departure, get DeltaV to imparted NEO
tool ready in a could of months
- Andres Glavez
"ESA Asteroid Mission Studies: What we have learnt"
Don Quijote was an interesting exercise
how can a generic precursor be defined? complicated missions, many options, have freedom how to select a target (not like reality), multiple trade-offs in architecture
clever use of orbital mechanics (Don Q. Mission): dual launch with spacecraft separated into different trajectories
flexible mission timelines
orbit stability
be prepared for the unexpected
mission layer is related to the type of information mission is expected to gather
radio science experiment: requires iterative process with determination of position and computation of position of asteroid
- Sam Wagner
"Robotic and Human Exploration/Deflection Mission Design for Asteroid Apophis"
Human mission requirements for 180 and 365 day crewed mission
2028/2029 human mission
two launch windows for each close encounter
180 days is the max for most NASA missions
for 2028/2029 launch dates, very small launch windows (2-12 days)
180 day summary, need 12 km/s
365 day mission: lower Delta V required, 6 km/s deltaV needed, similar to Ares I with Orion
Use Apophis for NEO missions, similar to Lunar deltaV with 6.5-7 km/s
Fictional crewed 2036 deflection missions: minimum one year mission length, 8.5 km/s deltaV
launch window exactly one year prior to impact, arrival 15 days prior to impact (only one chance)
Apophis arrival, departures, Earth arrival in last 1.5 months
Fictional post 2029 Intercept mission
continuously launch from 2035-2036, max deltaV is 4 km/s
arrival velocities from 0.09 - 20 km/s
Human pilot Mission Conclusions:
180 day mission: 11-12 km/s
365 mission: 6.5-7 km.s
- Erik Ball
"NEO Object Interception Using Nuclear Thermal Rocket Propulsion"
in place of Steven Hoewe
Scenario: Need to deflect large long Period Comet (10 km)
deflection or destruction
minimum energy for example is 3300 terajoules, thermonuclear explosion
NTR is very useful for such applications, CSNR worked on such NTRs,
chose NTR since high specific impulse (engine T/W, 6:1) up to 1000s ISP
ROVER/NERVA tests
yield requirements for deflection: scales linearly with comet size (effect based on comet properties are unknown), effects of trapped volatiles
surface burst or close standoff
40km/s: penetration impossible
Beta assumption: 3X10-4 (kg*m/s)/J
hundreds of megatons for large comet
independent variables: time of launch, angle of launch, rocket delta-V
optimize trade off between high mission deltaV and high payload mass
choose best engine size (larger engine is more mass but more thrust reduces gravity drag)
how crucial is an early launch (fast mission: 50 days before impact): high deltaV, later launches (12-27 days before impact) have 20-40 days for launch windows
early interceptor have a high fuel mass, low fuel mass but high payload mass, optimal point at about 17 days before impact (0.25 T/W of interceptor rocket)
Chemical rocket not a feasible rocket because mass to LEO is very high for chemical
even low thrust is too massive and not enough thrust for short time
3600 MT in LEO (very massive
how big could we deal with (21 HLLV in 2-3 months, carrying 20 MT interception - 1 MT is engine, most if fuel mass), 9 MT of payload, arrive at comet within 2 days of each other (7-8 month flight time), mission deltaV is 7 km/s
perhaps may be able to get up to 5 km diameter in terms of mitigation with feasible approaches
need to have technology ready perhaps
Day 3 (Wednesday 11 May 2011) Session 5
Campaign Planning
- J-T Grundman
AsteroidSQAUDS/iSSB - Synergistic NEO Deflection Campaign and Mitigation Effects Test Mission
DLR
reflection of past IAA 2009 conference white paper: campaign studies and focus on smaller objects
looking at desires of various missions: heavy launcher development, fast mission scenarios, low space debris generation, include amateurs,
small and smart interceptor design produced in advance of heavy launch vehicle development
launcher test schedule triggers search for suitable target (3-6 months to launch)
every month 8-20 known NEOs approach Earth within 0.2 AU
NEAs about the size of 100m chosen
instruments: ranger like camera bank, dust counters, plasma instruments
take the AsteroidFinder spacecraft
have a more modular approach to spacecraft development
using CEF (Concurrent Engineering Facility)
put a kit together
interceptor: 179 kg mass
fits in standard secondary payload volume
took a Ariane 5 model for heavy life (12 MT to GTO)
20 impactors on a launch vehicle
Use Shoemaker Levi 9 multiple impact scenario
Q: need for observer spacecraft for any deflection
A: not about a proper deflection (testing mission) - not a deflection
- A. Zimmer
"Target Selection and Mission Analysis of Human Exploration Missions to NEAs"
Univ. of Stuttgart
complex trade space, multiple NEAs too many filers, launch window investigation, mission abort options
better understanding of parameter space for trajectory options for human missions
accessibility model: pre-selection of asteroid, based on celestial mechanics rather than scientific gain
approach: based on upper stage performance, departure from LEO, two impulse round trip mission, termination condition: deltaV limit (first burn) <10k/s, mission duration <365 days
verification of model: used 7812 NEAs, size criterion (H<=25) and slow rotation rate, 6704 NEAS, then semi-major axis, eccentricity, inclination: 2567 NEAs, then termination condition:
left with 240 NEAs between 2010 and 2040
statisitics: most attractive tragets with deltaV<7.5 km/s left with 73 targets - most of PHAs, pre-dominantly Atens and Apollos, many targets require long missions and high DeltaV
absolute mag less than 22-only about 20 NEOs
170 launch windows between 2020 and 2040
gradually increase in mission duration and then increase time with 1 mission every 2 years
looking at anytime abort (duration of return to Earth minimized) and free return (delta V minimized)
only investigated outbound mission leg only (once at asteroid)
long missions (= 365 day return, free return possible, anytime abort is limited)
better understand of abort options and assessment of prx ops, and Near Earth Largrnage points
design a building block of architecture
- Sugimoto, Y.
"Effects of NEO Composition on Deflection Methodologies"
Univ. of Glasgow
Looking at short warning time cases
for small bodies mass is not always available and estimate from bulk density if highly unlikely
most abundant NEOs are S-type asteroids (about 50%)
evidence theory can quantify epistemic uncertainties without assuming a distribution function specific to asteroid composition
NEO properties: micro-density, micro-porosity, bulk porosity, and albedo (out dist. on those)
two measures of uncertainty: beliefs and plausibility
set scene, set a baseline composition: 40% bulk porosity and 3.6g/cm?^2, and 0m2 albedo
deviation required (1.66 Earth-radii and 2.5 Earth-radii safe distance)
three types of mitigation missions: kinetic, nuclear, and solar collector
Q: did listing of meteorite densities did it include all data: did not include data, only a fraction of data are usable since meteorites have been weathered and potential better samples needed that are less weathered and handled better
Q: what is important is physical properties
- Cyrus Foster
"Multiple Concepts and Operations for Asteroid Mitigation including Multiple Gravity Tractors"
Deflection campaigns uses more than gravity tractor
redundant gravity tractor for insurance against failure
how does deflection scale with use of multiple gravity tractors
three concepts: single gravity tractors at a time, simultaneously tractor GTs w/station keeping, simultaneously tracting with mechanical docking to form single gravity tractor
used Apophis
looking at six launch opportunities: sending single 1MT gravity tractor
Concept 1: single GT at a time
other GTs an acts are tracking and use as backup
simpler operational concept but poorer deflection, total deflection of 76.1 km
Concept 2: simultaneous GTs
station keep around single point (could also be interested in halo orbits)
enables simultaneous ops but
total deflection of 122.4 km
Concept 3: mechanical docking approach
eliminates strict station keeping requirements but requires mechanical interface and docking ops
Concept 3b: keep empty gravity tractor docked
total deflection of 134.6 km
for Apophis: docked stacking provided a 10% improvement,
Trajectory Browser Tool at NASA Ames (web based tool to search rendezvous opportunities)
transfer from Earth to 8k NEOs and user can access database and select constraints
database of 2 body ballistic trajectories for various missions configurations
Mission Design Center Small Body Missions at NASA Ames
currently a NASA internal website
Q: perhaps increase efficiency for concept 1 if one if to use expended GT is sent
Q: use kinetic impactor and GT to trim perhaps, that might be easier
A: for Apophis multiple gravity tractor is overkill for this example (just providing it for example)
Q: how robust is the scenario are, launching GT at different times, putting GT later
Q: Looked at refueling GTs
A: Have not considered
Q: is the NEO tool distinguish types of NEOs based upon quality of observations
A: Yes, have orbit condition code as user input
- Nahum Melamed
"Development of Handbook and an online tool on Defending Earth against potentially hazardous objects"
develop a handbook for kinetic impact
develop a web based resource center for first order deflection mission requirements
aid in KI design
outreach
characterize NEO, determine deflection maneuver by using Lambert solution, select launch vehicle, determine deltaV, determine B Plan position
currently development B plane position is finished, working on the determine the trajectory phase portion
available on JPL portal at future stage
Current state of the web tool (Phase 1a)
ongoing development, save and retrieve buttons, B-plan updates, add variable resolution on earth impacts, possibly to vary to DeltaV slides, show keyholes,
Phase 1b development:
integrate with launch capability and use LV payload planners guide, use Lambert solution to connect departure, get DeltaV to imparted NEO
tool ready in a could of months
- Andres Glavez
"ESA Asteroid Mission Studies: What we have learnt"
Don Quijote was an interesting exercise
how can a generic precursor be defined? complicated missions, many options, have freedom how to select a target (not like reality), multiple trade-offs in architecture
clever use of orbital mechanics (Don Q. Mission): dual launch with spacecraft separated into different trajectories
flexible mission timelines
orbit stability
be prepared for the unexpected
mission layer is related to the type of information mission is expected to gather
radio science experiment: requires iterative process with determination of position and computation of position of asteroid
- Sam Wagner
"Robotic and Human Exploration/Deflection Mission Design for Asteroid Apophis"
Human mission requirements for 180 and 365 day crewed mission
2028/2029 human mission
two launch windows for each close encounter
180 days is the max for most NASA missions
for 2028/2029 launch dates, very small launch windows (2-12 days)
180 day summary, need 12 km/s
365 day mission: lower Delta V required, 6 km/s deltaV needed, similar to Ares I with Orion
Use Apophis for NEO missions, similar to Lunar deltaV with 6.5-7 km/s
Fictional crewed 2036 deflection missions: minimum one year mission length, 8.5 km/s deltaV
launch window exactly one year prior to impact, arrival 15 days prior to impact (only one chance)
Apophis arrival, departures, Earth arrival in last 1.5 months
Fictional post 2029 Intercept mission
continuously launch from 2035-2036, max deltaV is 4 km/s
arrival velocities from 0.09 - 20 km/s
Human pilot Mission Conclusions:
180 day mission: 11-12 km/s
365 mission: 6.5-7 km.s
- Erik Ball
"NEO Object Interception Using Nuclear Thermal Rocket Propulsion"
in place of Steven Hoewe
Scenario: Need to deflect large long Period Comet (10 km)
deflection or destruction
minimum energy for example is 3300 terajoules, thermonuclear explosion
NTR is very useful for such applications, CSNR worked on such NTRs,
chose NTR since high specific impulse (engine T/W, 6:1) up to 1000s ISP
ROVER/NERVA tests
yield requirements for deflection: scales linearly with comet size (effect based on comet properties are unknown), effects of trapped volatiles
surface burst or close standoff
40km/s: penetration impossible
Beta assumption: 3X10-4 (kg*m/s)/J
hundreds of megatons for large comet
independent variables: time of launch, angle of launch, rocket delta-V
optimize trade off between high mission deltaV and high payload mass
choose best engine size (larger engine is more mass but more thrust reduces gravity drag)
how crucial is an early launch (fast mission: 50 days before impact): high deltaV, later launches (12-27 days before impact) have 20-40 days for launch windows
early interceptor have a high fuel mass, low fuel mass but high payload mass, optimal point at about 17 days before impact (0.25 T/W of interceptor rocket)
Chemical rocket not a feasible rocket because mass to LEO is very high for chemical
even low thrust is too massive and not enough thrust for short time
3600 MT in LEO (very massive
how big could we deal with (21 HLLV in 2-3 months, carrying 20 MT interception - 1 MT is engine, most if fuel mass), 9 MT of payload, arrive at comet within 2 days of each other (7-8 month flight time), mission deltaV is 7 km/s
perhaps may be able to get up to 5 km diameter in terms of mitigation with feasible approaches
need to have technology ready perhaps
NASA Ames Mission Design Center web based NEO browser tool to search pre computed trajectories
NASA Ames Mission Design Center is developing a web based NEO browser tool to search pre computed trajectories, database of 2 body ballistic trajectories for various mission configurations, could also filter by orbit condition codes, currently a NASA internal website but plans for public release
Image: twitpic
10 May 2011
2011 IAA Planetary Defense Conference: Day 2 Session 4
Notes from Day 2 of 2011 IAA Planetary Defense Conference. Follow twitter feed for more information:
Day 2 (Tuesday 10 May 2011) Session 4
Impact Consequences and Education
- Longo, G.
"Consequences of the Tunguska Impact and their Interpretation"
more than 100 theories of Tunguska event
many expeditions, 1991 Italian expedition to collect wood samples
new map obtained of 1908 treefall
from final traj. azimuths: single body trajectory or multiple bolide formed by two bodies
New hypothesis: Tunguska bolide underwent fragmentation or was a double body (perfers double body)
example crater to look at Carancas Crater
Lake Cheko: something perhaps under bottom of lake (reflection) (historical evidence refers to lake Cheko but not lake Cheko)
Several surviving trees have in 1908 an inclination toward the lake
Before 1908 think there was a forest before at the current lake location
Would like to drill to bottom of Lake Cheko - do not have the money to drill (but have plan), hopefully in the next decade can drill
http://www-th.bo.infn.it/tunguska
Q: Good to scrape enough particles (take logs apart), if get enough cromium could do isotopic analysis - could prove extraterrestrial nature
A: Have nanograms of particles in tree resin: possible consequence of body but cannot confirm (need to drill to bottom of Lake Cheko)
- Martin Mueller
"Creating Awareness" of the Impact Hazard
Univ. of Eichstaett-Ingolstadt
geographer
meteorite impact and their influence on human society are part of geography curriculum
interviews with experts and surveys of youth in Germany
Results:
the interest in meteorite impacts is above the expected average
both boys and girls are equally interested (not expected since boys more interested in natural disasters)
the interest is much higher in the 5th grade than in the 11th grade
for students, the issue of meteorites impacting today and consequences of a large impact are of highest interest (than pure natural science)
the more complex the concepts are they then are more in the way scientists think (perhaps specific to Germany)
students gather their knowledge from school and TV/movies
students do no know "nuclear winter"
students unaware of asteroid/comets
students do not know a single crater by name
most students are unaware of the geological timescale (missing a deep time framework)
two fundamentally different concepts could be identified" "hot stone in Earth orbit"
Have developed a website called CRATER with online calculator
central aim of future educational activities, covered best in geography classes
- Gritsevich, M.
"New Classification Scale for Impact Consequences"
MSU, University of Helsiknki (Russian Federation)
more reliable scale
non-dimensional parameters for asteroid entry
alpha: aerobraking efficiency
beta: fraction of KE to effective destructive enthalpy
u = meteorite rotation
- Mark Boslough
Airburst Warning and Response
looking at modeling airburst less as a point source, effects on ground greater than as point burst, policy implications of where community should go
LAA (low altitude airburst), talking referring to Harris event/mag chart and how difficult to visualize, reason airburst has gained interest is that larger objects have been mostly found
Two types of airbursts (Tunguska free fall and Libyan Desert glass)
nuclear airburst is a bubble, but asteroid energy is carried downward
Type 1 Tunguska airburst: fireball in sky, blast wave hitting ground
Type 2: fireball all the way to the ground
Kind Tut's scarab dung beetle - carved out of Libyan desert glass (referring to Anders Sandberg reference to searching for academic terms)
1908 Tunguska airburst 5 megatons (also trees potentially unhealthy so lower wind speeds could caused damage)
uncertainty quantification required
IPCC likelihood Scale - refer back to this for impact threat
politically relevant time scale is a decade (think in decade times of scales)
not paying attention to public concerns
probability of biggest impact in a decade - number of people - total number
integrates to 1363 (1409) deaths/year
current assessed threat = 126 (152) deaths/year
Future (after next survey) = 5 (17) deaths/year
point (non-point) values
we are going to be so successful that we will put ourselves out of business (for the next hundred years) - good news for humanity and bad news for this community
relative threat from airburst is increasing
100 Mt will dominate threat after current survey
mitigation should focus on small (~100m) NEOs
probability of an airburst in the next decade is about 1% (1 in a 1000 event) - Tunguska like
Probability that asteroid >140 m will be discovered in the next decade is on a collision course in the next century is about 0.1%
we are ~10 times more likely to save lives by reducing imminent impactors in the next survey
Evac plan needs to include uncertainty in size
NRC report: death lunge recommendation: next dangerous event is an airburst from <50m object, not a crater forming event
Proposed Bucharest style Airburst scale from 1 to 5
Research and Entertainment: TC3
Who would be willing to fund to witness the next TC3.
- G. Gisler, "Calculation of Impact of a Small Asteroid on a Continental Shelf"
should not call asteroid tsunami's tsunamis
what is the smallest size asteroid we need to defense against (200 m asteroid)
in Granada advocated: that is Apophis was targeting middle of Pacific because let it fall, well instrument with assets, to understand effects
of the ~200 recognized impact craters worldwide, very few are in the ocean (most on shelf)
tsunami deposits would be a sign of deep water impact
diameter of asteroid has to be 1/5 of depth of water
doing a continental shelf impact simulation, 200 m asteroid into a 100 m + 100 m sediment layers, 526 MT, used sage code with 1.5 m resolution using 200K of CPUs for 165 seconds of physical time
sediment-laden storm surge washes ashore with sand-blasting winds
Atmospheric effects from cont shelf are worse than impact tsunami, damage by blast wave and hot, fast winds
sediment laden surge is similar to powerful tropical storm
sediment on the shelf i lofted and then propelled by winds
propagation distance: 200 m impact (do not want to be 100km-200 km distance)
hydrocarbon finds craters on shelf (propitiatory data): lots more impacts on shelf
shelves are ideal for collapse and get most of tsunami like events
- Dragos Isvornau
"Dynamics of Tsunamis Generated by Asteroid Impact in the Black Sea"
- Verant, J.L
The protective role of Earth's atmosphere against the threat of asteroids"
Day 2 (Tuesday 10 May 2011) Session 4
Impact Consequences and Education
- Longo, G.
"Consequences of the Tunguska Impact and their Interpretation"
more than 100 theories of Tunguska event
many expeditions, 1991 Italian expedition to collect wood samples
new map obtained of 1908 treefall
from final traj. azimuths: single body trajectory or multiple bolide formed by two bodies
New hypothesis: Tunguska bolide underwent fragmentation or was a double body (perfers double body)
example crater to look at Carancas Crater
Lake Cheko: something perhaps under bottom of lake (reflection) (historical evidence refers to lake Cheko but not lake Cheko)
Several surviving trees have in 1908 an inclination toward the lake
Before 1908 think there was a forest before at the current lake location
Would like to drill to bottom of Lake Cheko - do not have the money to drill (but have plan), hopefully in the next decade can drill
http://www-th.bo.infn.it/tunguska
Q: Good to scrape enough particles (take logs apart), if get enough cromium could do isotopic analysis - could prove extraterrestrial nature
A: Have nanograms of particles in tree resin: possible consequence of body but cannot confirm (need to drill to bottom of Lake Cheko)
- Martin Mueller
"Creating Awareness" of the Impact Hazard
Univ. of Eichstaett-Ingolstadt
geographer
meteorite impact and their influence on human society are part of geography curriculum
interviews with experts and surveys of youth in Germany
Results:
the interest in meteorite impacts is above the expected average
both boys and girls are equally interested (not expected since boys more interested in natural disasters)
the interest is much higher in the 5th grade than in the 11th grade
for students, the issue of meteorites impacting today and consequences of a large impact are of highest interest (than pure natural science)
the more complex the concepts are they then are more in the way scientists think (perhaps specific to Germany)
students gather their knowledge from school and TV/movies
students do no know "nuclear winter"
students unaware of asteroid/comets
students do not know a single crater by name
most students are unaware of the geological timescale (missing a deep time framework)
two fundamentally different concepts could be identified" "hot stone in Earth orbit"
Have developed a website called CRATER with online calculator
central aim of future educational activities, covered best in geography classes
- Gritsevich, M.
"New Classification Scale for Impact Consequences"
MSU, University of Helsiknki (Russian Federation)
more reliable scale
non-dimensional parameters for asteroid entry
alpha: aerobraking efficiency
beta: fraction of KE to effective destructive enthalpy
u = meteorite rotation
- Mark Boslough
Airburst Warning and Response
looking at modeling airburst less as a point source, effects on ground greater than as point burst, policy implications of where community should go
LAA (low altitude airburst), talking referring to Harris event/mag chart and how difficult to visualize, reason airburst has gained interest is that larger objects have been mostly found
Two types of airbursts (Tunguska free fall and Libyan Desert glass)
nuclear airburst is a bubble, but asteroid energy is carried downward
Type 1 Tunguska airburst: fireball in sky, blast wave hitting ground
Type 2: fireball all the way to the ground
Kind Tut's scarab dung beetle - carved out of Libyan desert glass (referring to Anders Sandberg reference to searching for academic terms)
1908 Tunguska airburst 5 megatons (also trees potentially unhealthy so lower wind speeds could caused damage)
uncertainty quantification required
IPCC likelihood Scale - refer back to this for impact threat
politically relevant time scale is a decade (think in decade times of scales)
not paying attention to public concerns
probability of biggest impact in a decade - number of people - total number
integrates to 1363 (1409) deaths/year
current assessed threat = 126 (152) deaths/year
Future (after next survey) = 5 (17) deaths/year
point (non-point) values
we are going to be so successful that we will put ourselves out of business (for the next hundred years) - good news for humanity and bad news for this community
relative threat from airburst is increasing
100 Mt will dominate threat after current survey
mitigation should focus on small (~100m) NEOs
probability of an airburst in the next decade is about 1% (1 in a 1000 event) - Tunguska like
Probability that asteroid >140 m will be discovered in the next decade is on a collision course in the next century is about 0.1%
we are ~10 times more likely to save lives by reducing imminent impactors in the next survey
Evac plan needs to include uncertainty in size
NRC report: death lunge recommendation: next dangerous event is an airburst from <50m object, not a crater forming event
Proposed Bucharest style Airburst scale from 1 to 5
Research and Entertainment: TC3
Who would be willing to fund to witness the next TC3.
- G. Gisler, "Calculation of Impact of a Small Asteroid on a Continental Shelf"
should not call asteroid tsunami's tsunamis
what is the smallest size asteroid we need to defense against (200 m asteroid)
in Granada advocated: that is Apophis was targeting middle of Pacific because let it fall, well instrument with assets, to understand effects
of the ~200 recognized impact craters worldwide, very few are in the ocean (most on shelf)
tsunami deposits would be a sign of deep water impact
diameter of asteroid has to be 1/5 of depth of water
doing a continental shelf impact simulation, 200 m asteroid into a 100 m + 100 m sediment layers, 526 MT, used sage code with 1.5 m resolution using 200K of CPUs for 165 seconds of physical time
sediment-laden storm surge washes ashore with sand-blasting winds
Atmospheric effects from cont shelf are worse than impact tsunami, damage by blast wave and hot, fast winds
sediment laden surge is similar to powerful tropical storm
sediment on the shelf i lofted and then propelled by winds
propagation distance: 200 m impact (do not want to be 100km-200 km distance)
hydrocarbon finds craters on shelf (propitiatory data): lots more impacts on shelf
shelves are ideal for collapse and get most of tsunami like events
- Dragos Isvornau
"Dynamics of Tsunamis Generated by Asteroid Impact in the Black Sea"
- Verant, J.L
The protective role of Earth's atmosphere against the threat of asteroids"
Subscribe to:
Posts (Atom)