21 January 2010
Russian Scientists Discuss NEOs
"Russian scientists brace for approaching asteroid"
Russia Today (RT)
Published 20 January, 2010, 08:48
Russia’s space agency has been holding meetings about Apophis – the asteroid due to pass close to Earth in 2029. If it is not diverted, a collision could potentially kill millions, scientists say. “Apophis was discovered in 2004,” explains Boris Shustov, Director of the Institute of Astronomy. “The probability of a collision with the Earth was very high, about 1 to 30. The collision of such a large body with our planet will cause great damage."
Link: Russia Today News Report (20 January 2010)
"Armageddon 2036: Russian scientists say no"
Russia Today (RT)
Published 31 December, 2009, 01:52
A huge asteroid, 350 meters in diameter, will come dangerously close to Earth, risking a lethal crash with our planet. However, Russian Federal Space Agency says there are ways to avert the collision. A celestial body named Apophis – asteroid 2004 MN4 – is considered the greatest space danger for Earth. In 2029 it will pass within 30 thousand kilometers of Earth, closer than some orbital satellites. The greater danger, though, is to be expected in 2036 when the next encounter with Earth by the asteroid is planned – the trajectory of the celestial body is expected to change so that the collision is quite likely, the head of Federal Space Agency, Anatoly Perminov, said in an interview with the Voice of Russia radio. He mentioned the data comes from research by an unnamed scientist claiming the accident is almost inevitable.
Link: Russia Today News Report (31 December 2009)
2010 Mexico City Workshop on global asteroid monitoring network
Recently concluded workshop following upon the report last year by Association of Space Explorers (ASE) Committee on Near-Earth Objects (NEOs) and its Panel on Asteroid Threat Mitigation on recommendations for global information, mitigation, and decision-making as related to planetary defense.
The Association of Space Explorers co-sponsored with the Secure World Foundation a January workshop in Mexico City on an international Information, Analysis, and Warning network [IAWN] to distribute reliable information on hazardous NEOs. This is part of the proposal laid out in the ASE report for an IAWN.
Link: Astronaut Tom Jones Blog Article
The Association of Space Explorers co-sponsored with the Secure World Foundation a January workshop in Mexico City on an international Information, Analysis, and Warning network [IAWN] to distribute reliable information on hazardous NEOs. This is part of the proposal laid out in the ASE report for an IAWN.
Link: Astronaut Tom Jones Blog Article
Article: Sudan arrests Europeans over asteroid fragments
From Reuters:
KHARTOUM, Jan 19 (Reuters) - Sudanese police said on Tuesday they had arrested two European tourists for collecting fragments of an asteroid from the country's northern desert without permission.
The tourists, from France and Belgium, found pieces of an asteroid that crashed to earth in the Abu-Hamad area of Sudan's remote Northern state, said a statement published by Sudan's interior ministry.
"This was a clear violation and an illegal act because they didn't get the right permission from the geological or other relevant authorities," a police spokesman told Reuters.
The statement did not say what charges the Europeans might face.
Scientists tracked a car-sized asteroid as it entered the Earth's atmosphere and exploded over northern Sudan's Nubian desert in October 2008.
Experts from NASA and the University of Khartoum, collected fragments from the site soon afterwards.
They described the find as extremely rare as fragile asteroids usually explode high in the atmosphere and because it was the first time scientists had been able to predict an object was heading to earth and follow it to its final destination.
Sudan has very few tourists, largely thanks to its insecurity, cumbersome visa regulations and the restrictions on visitors' movements imposed when they arrive.
Link: Reuters Article
KHARTOUM, Jan 19 (Reuters) - Sudanese police said on Tuesday they had arrested two European tourists for collecting fragments of an asteroid from the country's northern desert without permission.
The tourists, from France and Belgium, found pieces of an asteroid that crashed to earth in the Abu-Hamad area of Sudan's remote Northern state, said a statement published by Sudan's interior ministry.
"This was a clear violation and an illegal act because they didn't get the right permission from the geological or other relevant authorities," a police spokesman told Reuters.
The statement did not say what charges the Europeans might face.
Scientists tracked a car-sized asteroid as it entered the Earth's atmosphere and exploded over northern Sudan's Nubian desert in October 2008.
Experts from NASA and the University of Khartoum, collected fragments from the site soon afterwards.
They described the find as extremely rare as fragile asteroids usually explode high in the atmosphere and because it was the first time scientists had been able to predict an object was heading to earth and follow it to its final destination.
Sudan has very few tourists, largely thanks to its insecurity, cumbersome visa regulations and the restrictions on visitors' movements imposed when they arrive.
Link: Reuters Article
20 January 2010
Impact of Earth's Gravity on Nearby Asteroids
From MIT News Release...
For decades, astronomers have analyzed the impact that asteroids could have on Earth. New research by MIT Professor of Planetary Science Richard Binzel examines the opposite scenario: that Earth has considerable influence on asteroids — and from a distance much larger than previously thought. The finding helps answer an elusive, decades-long question about where most meteorites come from before they fall to Earth and also opens the door to a new field study of asteroid seismology.
By analyzing telescopic measurements of near-Earth asteroids (NEAs), or asteroids that come within 30 million miles of Earth, Binzel has determined that if an NEA travels within a certain range of Earth, roughly one-quarter of the distance between Earth and the moon, it can experience a “seismic shake” strong enough to bring fresh material called “regolith” to its surface. These rarely seen “fresh asteroids” have long interested astronomers because their spectral fingerprints, or how they reflect different wavelengths of light, match 80 percent of all meteorites that fall to Earth, according to a paper by Binzel appearing in the Jan. 21 issue of Nature. The paper suggests that Earth’s gravitational pull and tidal forces create these seismic tremors.
By hypothesizing about the cause of the fresh surfaces of some NEAs, Binzel and his colleagues have tried to solve a decades-long conundrum about why these fresh asteroids are not seen in the main asteroid belt, which is between Mars and Jupiter. They believe this is because the fresh surfaces are the result of a close encounter with Earth, which obviously wouldn’t be the case with an object in the main asteroid belt. Only those few objects that have ventured recently inside the moon’s orbital distance and have experienced a “fresh shake” match freshly fallen meteorites measured in the laboratory, Binzel said.
Clark Chapman, a planetary scientist at the Southwest Research Institute in Colorado, believes Binzel’s work is part of a “revolution in asteroid science” over the past five years that considers the possibility that something other than collisions can affect asteroid surfaces.
How they did it: Binzel’s team used a large NASA telescope in Hawaii to collect information on NEAs, including a huge amount of spectral fingerprint data. Analyzing this data, the group examined where a sample of 95 NEAs had been during the past 500,000 years, tracing their orbits to see how close they’d come to Earth. They discovered that 75 NEAs in the sample had passed well inside the moon’s distance within the past 500,000 years, including all 20 fresh asteroids in the sample.
Binzel next determined that an asteroid traveling within a distance equal to 16 times the Earth’s radius (about one-quarter of the distance to the moon) appears to experience vibrations strong enough to create fresh surface material. He reached that figure based on his finding that about one-quarter of NEAs are fresh, as well as two known facts — that the space weathering process that ages regolith can happen in less than one million years, and that about one-quarter of NEAs come within 16 Earth radii in one million years.
Before now, people thought an asteroid had to come within one to two Earth radii to undergo significant physical change.
Next steps: Many details about the shaking process remain unknown, including what exactly it is about Earth that shakes the asteroids, and why this happens from a distance as far away as 16 Earth radii. What is certain is that the conditions depend on complex factors such as the velocity and duration of the encounter, the asteroid’s shape and the nature of the preexisting regolith. “The exact trigger distance depends on all those seismology factors that are the totally new and interesting area for cutting edge research,” Binzel said.
Further research might include computer simulations, ground observations and sending probes to look at the surfaces of asteroids. Binzel’s next steps will be to try to discover counterexamples to his findings or additional examples to support it. He may also investigate whether other planets like Venus or Mars affect asteroids that venture close to them.
Link: MIT News Release
From Discovery News Article...
New research published in this week's Nature shows Earth's gravity triggers ground-shifting quakes on asteroids passing as far as about 30 million miles away.
The findings may not only help scientists deflect an Earth-bound asteroid, but also provide fresh insights into the connections between asteroids and meteorites.
Scientists made the discovery by comparing differences in light reflected off asteroids that have breezed by Earth with those that orbit farther away. Though they are made of the same materials, the asteroids that encounter Earth's gravity have fresh surfaces that are noticeably less weathered by the space environment.
Scientists believe the resurfacing is due to slow-falling landslides, triggered by tidal forces from Earth.
"Asteroids get sunburned out there by the light from the sun, the radiation from the sun," Dan Durda, a planetary scientist with the Southwest Research Institute in Boulder, Colo., told Discovery News.
Backtracking the orbits of 95 near-Earth asteroids, scientists determined that over the past 500,000 years, 75 of them had passed closer to Earth than the moon, which is about 239,000 miles (or about 385,000 kilometers) away. The 75 asteroids included 20 bodies with spectra of fresh surface materials.
Link: Article (Discovery News)
Nature Magazine (editor's summary)..
The 'ordinary chondrite problem' has been a factor in Solar System astronomy for three decades. It refers to the apparent anomaly that whereas about 80% of the meteorites falling to Earth are 'ordinary chondrites', they are rare among asteroids. The usual explanation is that 'space weathering' processes alter ordinary chondrite surfaces, producing reddened 'S-type' asteroids. A mystery remains, though, in the shape of a rare class of asteroids, the Q-types. These are found only near the Earth, and they do display 'fresh' spectral matches to ordinary chondrites. Now the combination of a new data set of 95 asteroid spectra with their detailed orbital histories shows that all Q-type asteroids have recently passed close to Earth at least within the lunar distance. Thus tidal stresses or seismic shaking during these encounters may have exposed new unweathered material on the surface. Intriguingly a test of this hypothesis may be at hand: 99942 Apophis, a potentially Earth-threatening asteroid currently displaying 'weathered' spectral colours, is due to pass within six orbital radii of Earth in 2029. It is predicted that it will experience a seismic 'fresh shake', which should expose new unreddened material on the surface.
Link: Nature Magazine (Editor's Summary)
For decades, astronomers have analyzed the impact that asteroids could have on Earth. New research by MIT Professor of Planetary Science Richard Binzel examines the opposite scenario: that Earth has considerable influence on asteroids — and from a distance much larger than previously thought. The finding helps answer an elusive, decades-long question about where most meteorites come from before they fall to Earth and also opens the door to a new field study of asteroid seismology.
By analyzing telescopic measurements of near-Earth asteroids (NEAs), or asteroids that come within 30 million miles of Earth, Binzel has determined that if an NEA travels within a certain range of Earth, roughly one-quarter of the distance between Earth and the moon, it can experience a “seismic shake” strong enough to bring fresh material called “regolith” to its surface. These rarely seen “fresh asteroids” have long interested astronomers because their spectral fingerprints, or how they reflect different wavelengths of light, match 80 percent of all meteorites that fall to Earth, according to a paper by Binzel appearing in the Jan. 21 issue of Nature. The paper suggests that Earth’s gravitational pull and tidal forces create these seismic tremors.
By hypothesizing about the cause of the fresh surfaces of some NEAs, Binzel and his colleagues have tried to solve a decades-long conundrum about why these fresh asteroids are not seen in the main asteroid belt, which is between Mars and Jupiter. They believe this is because the fresh surfaces are the result of a close encounter with Earth, which obviously wouldn’t be the case with an object in the main asteroid belt. Only those few objects that have ventured recently inside the moon’s orbital distance and have experienced a “fresh shake” match freshly fallen meteorites measured in the laboratory, Binzel said.
Clark Chapman, a planetary scientist at the Southwest Research Institute in Colorado, believes Binzel’s work is part of a “revolution in asteroid science” over the past five years that considers the possibility that something other than collisions can affect asteroid surfaces.
How they did it: Binzel’s team used a large NASA telescope in Hawaii to collect information on NEAs, including a huge amount of spectral fingerprint data. Analyzing this data, the group examined where a sample of 95 NEAs had been during the past 500,000 years, tracing their orbits to see how close they’d come to Earth. They discovered that 75 NEAs in the sample had passed well inside the moon’s distance within the past 500,000 years, including all 20 fresh asteroids in the sample.
Binzel next determined that an asteroid traveling within a distance equal to 16 times the Earth’s radius (about one-quarter of the distance to the moon) appears to experience vibrations strong enough to create fresh surface material. He reached that figure based on his finding that about one-quarter of NEAs are fresh, as well as two known facts — that the space weathering process that ages regolith can happen in less than one million years, and that about one-quarter of NEAs come within 16 Earth radii in one million years.
Before now, people thought an asteroid had to come within one to two Earth radii to undergo significant physical change.
Next steps: Many details about the shaking process remain unknown, including what exactly it is about Earth that shakes the asteroids, and why this happens from a distance as far away as 16 Earth radii. What is certain is that the conditions depend on complex factors such as the velocity and duration of the encounter, the asteroid’s shape and the nature of the preexisting regolith. “The exact trigger distance depends on all those seismology factors that are the totally new and interesting area for cutting edge research,” Binzel said.
Further research might include computer simulations, ground observations and sending probes to look at the surfaces of asteroids. Binzel’s next steps will be to try to discover counterexamples to his findings or additional examples to support it. He may also investigate whether other planets like Venus or Mars affect asteroids that venture close to them.
Link: MIT News Release
New research published in this week's Nature shows Earth's gravity triggers ground-shifting quakes on asteroids passing as far as about 30 million miles away.
The findings may not only help scientists deflect an Earth-bound asteroid, but also provide fresh insights into the connections between asteroids and meteorites.
Scientists made the discovery by comparing differences in light reflected off asteroids that have breezed by Earth with those that orbit farther away. Though they are made of the same materials, the asteroids that encounter Earth's gravity have fresh surfaces that are noticeably less weathered by the space environment.
Scientists believe the resurfacing is due to slow-falling landslides, triggered by tidal forces from Earth.
"Asteroids get sunburned out there by the light from the sun, the radiation from the sun," Dan Durda, a planetary scientist with the Southwest Research Institute in Boulder, Colo., told Discovery News.
Backtracking the orbits of 95 near-Earth asteroids, scientists determined that over the past 500,000 years, 75 of them had passed closer to Earth than the moon, which is about 239,000 miles (or about 385,000 kilometers) away. The 75 asteroids included 20 bodies with spectra of fresh surface materials.
Link: Article (Discovery News)
Nature Magazine (editor's summary)..
The 'ordinary chondrite problem' has been a factor in Solar System astronomy for three decades. It refers to the apparent anomaly that whereas about 80% of the meteorites falling to Earth are 'ordinary chondrites', they are rare among asteroids. The usual explanation is that 'space weathering' processes alter ordinary chondrite surfaces, producing reddened 'S-type' asteroids. A mystery remains, though, in the shape of a rare class of asteroids, the Q-types. These are found only near the Earth, and they do display 'fresh' spectral matches to ordinary chondrites. Now the combination of a new data set of 95 asteroid spectra with their detailed orbital histories shows that all Q-type asteroids have recently passed close to Earth at least within the lunar distance. Thus tidal stresses or seismic shaking during these encounters may have exposed new unweathered material on the surface. Intriguingly a test of this hypothesis may be at hand: 99942 Apophis, a potentially Earth-threatening asteroid currently displaying 'weathered' spectral colours, is due to pass within six orbital radii of Earth in 2029. It is predicted that it will experience a seismic 'fresh shake', which should expose new unreddened material on the surface.
Link: Nature Magazine (Editor's Summary)
Asteroids: Stripped on passing by Earth
Nature 463, 305-306 (21 January 2010) | doi:10.1038/463305a; Published online 20 January 2010
Clark R. Chapman
Clark R. Chapman is in the Department of Space Studies, Southwest Research Institute, Boulder, Colorado 80302, USA.
Email: cchapman@boulder.swri.edu
Email: cchapman@boulder.swri.edu
Abstract:
Asteroids are weakly bound piles of rubble, and if one comes close to Earth, tides can cause the object to undergo landslides and structural rearrangement. The outcome of this encounter is a body with meteorite-like colours. We once thought that small asteroids were solid 'chips off the old block'. Instead, in a developing story, they are now known to be ephemeral piles of boulders in near-zero gravity, constantly evolving from delicate forces never before thought important.
Earth encounters as the origin of fresh surfaces on near-Earth asteroids
Nature 463, 331-334 (21 January 2010) | doi:10.1038/nature08709; Received 2 October 2009; Accepted 18 November 2009
Richard P. Binzel1,2, Alessandro Morbidelli3, Sihane Merouane4, Francesca E. DeMeo4, Mirel Birlan2, Pierre Vernazza5, Cristina A. Thomas6, Andrew S. Rivkin7, Schelte J. Bus8 & Alan T. Tokunaga8
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Institut de Mecanique Celeste et de Calcul des Ephemerides (IMCCE), Observatoire de Paris, Paris 75014, France
- Departement Cassiopee, Université de Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d’Azur, Nice 06304, France
- Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique (LESIA), Observatoire de Paris, Meudon 92195, France
- ESTEC/ESA, Noordwijk 2200 AG, Netherlands
- Department of Physics and Astronomy, Northern Arizona University, Flagstaff, Arizona 86011, USA
- Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland 20723, USA
- Institute for Astronomy, University of Hawaii, Hilo, Hawaii 96720, USA
Correspondence to: Richard P. Binzel1,2 Correspondence and requests for materials should be addressed to R.P.B. (Email: rpb@mit.edu).
Abstract:
Telescopic measurements of asteroids’ colours rarely match laboratory reflectance spectra of meteorites owing to a ‘space weathering’1, 2 process that rapidly3 reddens asteroid surfaces in less than 106 years. ‘Unweathered’ asteroids (those having spectra matching the most commonly falling ordinary chondrite meteorites), however, are seen among small bodies the orbits of which cross inside Mars and the Earth. Various explanations have been proposed for the origin of these fresh surface colours, ranging from collisions4 to planetary encounters5. Less reddened asteroids seem to cross most deeply into the terrestrial planet region, strengthening6 the evidence for the planetary-encounter theory5, but encounter details within 106 years remain to be shown. Here we report that asteroids displaying unweathered spectra (so-called ‘Q-types’7) have experienced orbital intersections closer than the Earth–Moon distance within the past 5 × 105 years. These Q-type asteroids are not currently found among asteroids showing no evidence of recent close planetary encounters. Our results substantiate previous work5: tidal stress8, strong enough to disturb and expose unweathered surface grains, is the most likely dominant short-term asteroid resurfacing process. Although the seismology details are yet to be worked out, the identification of rapid physical processes that can produce both fresh and weathered asteroid surfaces resolves the decades-long9 puzzle of the difference in colour of asteroids and meteorites.
13 January 2010
Radar returns from asteroid 2010AL30
From the Planetary Society blog...
Goldstone detects "STRONG" radar echoes from 2010 AL30
Jan. 12, 2010 | 21:05 PST
Radio scientist Lance Benner posted to the Minor Planets Mailing list this evening the following message:
All,
We have detected STRONG radar echoes from 2010 AL30 at Goldstone. The bandwidth is consistent with the object's expected size and the ~9 minute rotation period found by Bill Ryan and Richard Miles. We hope to obtain a precise size estimate soon.
The Doppler correction came in at about the 1-sigma level relative to our a priori estimate. We're updating the ephemeris now. Thank you again for all your help!
Nine-minute rotation? That is fast!! The observations of 2010 AL30 from Goldstone took place from 2:20 to 4:40 UTC on January 13.
When Benner says "thank you for all your help," his message is addressed to amateur astronomers around the world who pointed their telescopes at 2010 AL30 upon its approach, gathering information that helped to refine its orbit. In an earlier message to the group, Benner said "The pointing uncertainties have shrunk from about 523 arcseconds to about 11 arcsec at the start of tonight's track. Without all the astrometry you have reported, our observations would not be possible."
Although no backyard 'scope can equal the capability of Goldstone to measure the shape, size, and physical properties of an asteroid, Goldstone depends upon accurate positional information for its pointing. I'm sure they could have detected 2010 AL30 with less precise information; but to point in exactly the right direction results in much stronger echoes from the asteroid, improving the quality of their data by leaps and bounds. And being able to point so precisely might have been what allowed Benner to get time on such an important instrument on such short notice -- I'm not sure.
That's my favorite aspect of the study of near-Earth objects: the way that the science benefits from the participation of people at extremes of the observing spectrum, from the serious but amateur backyard astronomer to the scientists who run the world's largest telescopes.
I'll keep my eyes peeled for further science results from Goldstone's observations of 2010 AL30, and remember how they benefited from the help of amateurs.
A final note: JPL issued a statement this afternoon that contradicted some speculation across the Web, that because 2010 AL30 has a 1-year orbit that it might be an Earth artifact -- a lost rocket stage or some such thing. Although it does have a 1-year orbital period, "this object's orbit reaches the orbit of Venus at its closest point to the sun and nearly out to the orbit of Mars at its furthest point, crossing the Earth's orbit at a very steep angle. This makes it very unlikely that 2010 AL30 is a rocket stage. Furthermore, trajectory extrapolations show that this object cannot be associated with any recent launch and it has not made any close approaches to the Earth since well before the Space Age began. It seems more likely that this is a near-Earth asteroid about 10-15 meters in size...."
Goldstone detects "STRONG" radar echoes from 2010 AL30
Jan. 12, 2010 | 21:05 PST
Radio scientist Lance Benner posted to the Minor Planets Mailing list this evening the following message:
All,
We have detected STRONG radar echoes from 2010 AL30 at Goldstone. The bandwidth is consistent with the object's expected size and the ~9 minute rotation period found by Bill Ryan and Richard Miles. We hope to obtain a precise size estimate soon.
The Doppler correction came in at about the 1-sigma level relative to our a priori estimate. We're updating the ephemeris now. Thank you again for all your help!
Nine-minute rotation? That is fast!! The observations of 2010 AL30 from Goldstone took place from 2:20 to 4:40 UTC on January 13.
When Benner says "thank you for all your help," his message is addressed to amateur astronomers around the world who pointed their telescopes at 2010 AL30 upon its approach, gathering information that helped to refine its orbit. In an earlier message to the group, Benner said "The pointing uncertainties have shrunk from about 523 arcseconds to about 11 arcsec at the start of tonight's track. Without all the astrometry you have reported, our observations would not be possible."
Although no backyard 'scope can equal the capability of Goldstone to measure the shape, size, and physical properties of an asteroid, Goldstone depends upon accurate positional information for its pointing. I'm sure they could have detected 2010 AL30 with less precise information; but to point in exactly the right direction results in much stronger echoes from the asteroid, improving the quality of their data by leaps and bounds. And being able to point so precisely might have been what allowed Benner to get time on such an important instrument on such short notice -- I'm not sure.
That's my favorite aspect of the study of near-Earth objects: the way that the science benefits from the participation of people at extremes of the observing spectrum, from the serious but amateur backyard astronomer to the scientists who run the world's largest telescopes.
I'll keep my eyes peeled for further science results from Goldstone's observations of 2010 AL30, and remember how they benefited from the help of amateurs.
A final note: JPL issued a statement this afternoon that contradicted some speculation across the Web, that because 2010 AL30 has a 1-year orbit that it might be an Earth artifact -- a lost rocket stage or some such thing. Although it does have a 1-year orbital period, "this object's orbit reaches the orbit of Venus at its closest point to the sun and nearly out to the orbit of Mars at its furthest point, crossing the Earth's orbit at a very steep angle. This makes it very unlikely that 2010 AL30 is a rocket stage. Furthermore, trajectory extrapolations show that this object cannot be associated with any recent launch and it has not made any close approaches to the Earth since well before the Space Age began. It seems more likely that this is a near-Earth asteroid about 10-15 meters in size...."
12 January 2010
Asteroid 2010 AL30 Close Approach on January 13, 2010 (76,000 miles)
Orbital diagram depicts the trajectory of asteroid 2010 AL30 during its flyby of Earth in the early morning hours of Jan. 13 (Credit: NASA JPL)
2010 AL30 as imaged remotely from Australia on Jan. 11, 2010 (Ernesto Guido & Giovanni Sostero)
From NASA JPL:
Asteroid 2010 AL30, discovered by the LINEAR survey of MIT's Lincoln Laboratories on Jan. 10, will make a close approach to the Earth's surface to within 76,000 miles on Jan. 13 at 12:46 pm Greenwich time (7:46 am EST, 4:46 am PST). Because its orbital period is nearly identical to the Earth's one year period, some have suggested it may be a manmade rocket stage in orbit about the sun. However, this object's orbit reaches the orbit of Venus at its closest point to the sun and nearly out to the orbit of Mars at its furthest point, crossing the Earth's orbit at a very steep angle. This makes it very unlikely that 2010 AL30 is a rocket stage. Furthermore, trajectory extrapolations show that this object cannot be associated with any recent launch and it has not made any close approaches to the Earth since well before the Space Age began.
It seems more likely that this is a near-Earth asteroid about 10-15 meters in size, one of approximately 2 million such objects in near-Earth space. One would expect a near-Earth asteroid of this size to pass within the moon's distance about once every week on average. The asteroid does not pose a risk, in fact, stony asteroids under 25 meters in diameter would be expected to burn up in our atmosphere, causing little or no ground damage.
Link: NASA JPL Asteroid Watch
Link: Discovery News
UN COPUOS Scientific and Technical Subcommittee for February 2010: NEO Portion
From the agenda for the UN COPUOS Scientific and Technical Subcommittee meeting (8-19 February 2010, United Nation Office at Vienna, Vienna International Center, Vienna, Austria). The section on NEOs follows:
12. Near-Earth objects
In paragraph 9 of its resolution 64/86, the General Assembly agreed that the Subcommittee should reconvene its Working Group on Near-Earth Objects.
The Working Group will continue the work begun during the intersessional period on drafting international procedures for handling the threat posed by near-Earth objects (NEOs) and seek agreement on those procedures, review progress on international cooperation and collaboration on NEO observations, and facilitate, for the purpose of NEO threat detection, a more robust international capability for the exchange, processing, archiving and dissemination of data.9 The Subcommittee will have before it a report containing information on research in the field of near-Earth objects carried out by member States, international organizations and other entities (A/AC.105/949). In addition, the fourth interim report of the Action Team on Near-Earth Objects will be made available to the Subcommittee.
Link: Scientific and Technical Subcommittee: 2010, Forty-seventh session, 8-19 February 2010.
12. Near-Earth objects
In paragraph 9 of its resolution 64/86, the General Assembly agreed that the Subcommittee should reconvene its Working Group on Near-Earth Objects.
The Working Group will continue the work begun during the intersessional period on drafting international procedures for handling the threat posed by near-Earth objects (NEOs) and seek agreement on those procedures, review progress on international cooperation and collaboration on NEO observations, and facilitate, for the purpose of NEO threat detection, a more robust international capability for the exchange, processing, archiving and dissemination of data.9 The Subcommittee will have before it a report containing information on research in the field of near-Earth objects carried out by member States, international organizations and other entities (A/AC.105/949). In addition, the fourth interim report of the Action Team on Near-Earth Objects will be made available to the Subcommittee.
Link: Scientific and Technical Subcommittee: 2010, Forty-seventh session, 8-19 February 2010.
11 January 2010
Article: NASA’s Flexible Path evaluation of 2025 human mission to visit an asteroid
NASA managers have created an evaluation and roadmap for a potential human mission to visit the 1999 AO10 Near Earth Object (NEO) as early as 2025, as part of their options under the Flexible Path approach to the future of Human Space Flight. The mission would focus on using the International Space Station (ISS) as a testbed, with the ultimate focus on eventually heading to Mars.
However, the internal 65 page Flexible Path presentation – available on L2 – presented several possible directions NASA may take under the Augustine Commission’s Flexible Path option, including the outlining of a NEO mission in the mid-2020s, a full five to six years after the original target date to return to the moon, as outlined in the Vision of Space Exploration (VSE) – which is no longer seen as achievable.
Further information on the number of NEOs and PHOs will be forthcoming via “Next Generation Surveys such as LSST & Pan-STARRS, along with current on-going surveys, (which) expect to find many more NEOs and PHOs. The next generation surveys includes: Tracking (for better orbit determination). Characterization (taxonomy, minerals, volatiles, etc.). NEO-WISE is expected to find a few hundred NEOs in the next year.”
Based on the NEOs of interest – ones which are potential targets for a sending an expedition to visit – NASA has estimated 39 are accessible “based on a flight system assumptions consistent with a single Ares V-class launch.”
These targets have been generated from a list of NEOs already identified as accessible by human missions lasting up to a year, along with the viable outbound transit time for typical robotic missions to the same targets – resulting in multiple opportunities for human missions, and multiple opportunities also for precursor robotic missions in earlier years.
The scenario that was chosen for the purpose of the proposal to visit a NEO, targets the NEO “1999 AO10″ – which holds three human launch opportunities in 2025, 2026 and 2032 – with three robotic precursor opportunities in 2019, 2020, or 2021.
For the scenario used by the Flexible Path presentation, a five to six month long duration flight is installed into the roadmap for the human expedition to the asteroid, and importantly is classed as a vital element of the overall mission – countering claims that robotics can carry out all the requirements of the mission on their own.
“A robotic precursor would have been conducted ~4 years prior to a human NEO mission. A typical piloted “sprint” mission would be ~155 days in duration,” continued the presentation.
“Instruments would include teleoperated rovers or hoppers (multiple trips to/from surface); multi-wavelength radar system (HGA could be used to perform radar tomography of the NEO to obtain internal structure); and small instrument packages for precision deployment by the crew during EVA or with a robotic rover system.
“The human crew would provide: adaptability and ingenuity to deal with complex issues in real time; direct interaction with the surface via a variety of methods; and wide-ranging E/PO activities including HD video of humans at another world.”
Link: SpaceflightNow Article
05 January 2010
References for Previous Human NEO Missions
I have gathered several papers on previous human NEO mission design studies. These are listed on a separate references page.
04 January 2010
Lockheed Martin Human Asteroid Mission Presentation
Charts from Lockheed Martin on their Human Asteroid Mission design ("Plymouth Rock: An Early Human Asteroid Mission Using Orion") are now available on the corporate website. This design study was was presented at the Small Bodies Assessment Group meeting in November 18–19, 2009 in Boulder, Colorado. Josh Hopkins and Adam Dissel from Lockheed Martin Space Systems presented the study.
The architecture utilizes two ETO launches: an Ares V with an unmanned Orion CEV + EDS and an Ares I with a manned Orion CEV. Thus the dual-Orion in-space configuration that has been talked about in the media. For an initial target 2008 EA9 was chosen for a 2019 opportunity (total mission DV = 4.9 km/s, total 205 Day mission duration).
Some quick observations from the study:
* Six months appears to be the upper limit of feasible mission durations using dual Orion (for two people)
* Repeat opportunities with a specific asteroid are usually decades apart
* At the current asteroid discovery rate, the number of known mission opportunities in this time frame may double by 2015
* Orion-based asteroid missions require launch of about 46 tons to C3 = +1 to +4 km2/s2 (slightly faster than escape velocity)
* This is roughly equivalent to launching 50-65 mt to translunar injection (C3 = -1.8 km2/s2) depending on the launch approach, the planned Ares V capability has margin for this mission
Link: Lockheed Martin Human Asteroid Mission Presentation Charts (NASA Small Bodies Assessment Group meeting, November 2009)
Link: General Lockheed Martin Orion Corporate Page
Subscribe to:
Posts (Atom)