This area will cover relevant news of the threat to the planet from Near Earth Objects (NEOs) including concepts and designs for mitigation. All opinions are those of the author.

31 March 2010

SciAm Article on Inclusion of Climate Change Fatality Rate in Recent NRC NEO Report

From the article...

If you ask the average person whether in the long run it is climate change or an asteroid/comet impact that's expected to kill more people annually, you'll undoubtedly get some confused replies. Those asteroid movies are scary, but there are no verified instances of an asteroid strike killing any humans, are there? Meanwhile, the science of climate change is currently being overshadowed by a media-driven public debate, mainly in the U.S.

In fact, the expected annual fatality rate due to climate change is estimated to be far higher than that due to an asteroid or comet impact—150,000 versus 91, per the World Health Organization (WHO) and Alan Harris of the Space Science Institute, respectively. You won't, however, see that 150,000 figure in the main body of the Washington, D.C.–based National Research Council report on near-Earth object (NEO) surveys and mitigation strategies. (The report was written by a total of 42 scientists.)

Instead, in a chart on page 26 of the report on "expected fatalities per year, worldwide, from a variety of causes," asteroids are compared with shark attacks (three to seven deaths), firearms accidents (2,500), earthquakes (36,000), malaria (one million), traffic accidents (1.2 million), air pollution (two million), HIV/AIDS (2.1 million) and tobacco (five million).

Meanwhile, climate change is mentioned in a note beneath the chart, regarding one of the authors: "Mark Boslough wanted an additional entry in this table for fatalities due to climate change. The steering committee disagreed with including this entry because it did not think a reliable estimate is available, among other reasons. Dr. Boslough has written a minority opinion as Appendix D."

"Competing Catastrophes: What's the Bigger Menace, an Asteroid Impact or Climate Change?"
Robin Lloyd
31 March 2010
Scientific American

Link: Scientific American Article (Competing Catastrophes: What's the Bigger Menace, an Asteroid Impact or Climate Change?, 31 March 2010)

Dr. Peter Jenniskens Talking About Asteroid 2008 TC3 (also Future Talk on 09 April 2010 at UC Berkeley)

Dr. Peter Jenniskens of The SETI Institute will talk on 09 April 2010 at the University of California (UC) Berkeley, 110 Sproul Hall, Berkeley, CA 94720 (3-4 p.m., Silver Space Sciences Lab, Addition conference room 105). His talk will be part of the Space Sciences Lab Colloquium with the title of the talk being "The impact and recovery of asteroid 2008 TC3 Colloquium. Here are some other videos of Dr. Jenniskens discussing 2008 TC3.

Link: Event Information (Space Sciences Lab Colloquium: The impact and recovery of asteroid 2008 TC3)

Dr. Peter Jenniskens of The SETI Institute at last year's 2008 TC3 Workshop in the Sudan.

Link: YouTube Video (2008 TC3 Workshop with Dr. Peter Jenniskens)

Link: WORKSHOP ON ASTEROID 2008 TC3, University of Khartoum, Khartoum, Sudan, 5-15 December 2009

Also a link to a seminar given by Dr. Jenniskens on the recovery of 2008 TC3.

Link: YouTube Video (SETI Seminars: Peter Jenniskens)

30 March 2010

Reported Pieces of 2008 TC3 Up for Sale on eBay

Multiple eBay items are available that report to be pieces of the Almahata Sitta 2008 TC3 meteorite that fell in 2008 in the Sudan.

Item number: 260576363419. The first item (item location: Oberwesel-Loreley Middle Rhine, Germany) seems to be from Stephan u. Gabriele Decker (, seller: donnersteine):

Item number: 260576516106. This second item (item location: Brooklyn, NY, US) seems to be from Shawn Alan (seller: photophlow):
Link: eBay item (Almahata Sitta 2008 TC3 meteorite micro Ureilite)

Item number: 380219553638. The third item (item location: Bern, Switzerland) (seller: pema9):
Link: eBay item (Meteorite ALMAHATA SITTA aka TC3 1st observed in Space!)

Item number: 280485715930. The fourth item (item location: Algenstedt, Germany) (seller: abdulalhazzra):
Link: eBay item (Almahata Sitta - polymict Ureilite-an - TC3)

Planetary Report from The Planetary Society: Jan./Feb. 2010 Issue on NEOs

Update: Secure World Foundation (SWF) has made the recent issue of The Planetary Report dealing with NEOs available online (I have also posted it in the blog library). They have a Press Release about it as well.

The Planetary Report from The Planetary Society (Volume XXX, Number 1, January/February 2010) contains multiple articles on NEOs (including many images/visualizations developed by SpaceWorks on NEOs)

From the Secure World Foundation press release...

A partnership between Secure World Foundation and The Planetary Society has created a special publication devoted to “Defending Our World” – an impressive look at the threat to Earth from asteroids and comets. This special issue of The Planetary Report has been produced by The Planetary Society and focuses on planetary defense, containing key articles, such as:

-- Protecting the Earth: Whose Job Is It?
-- To Move an Asteroid
-- Turning Cosmic Disaster Into Opportunity
-- We Make It Happen! Doing Our Part to Protect Earth

Link: The Planetary Society Website: The Planetary Report, Volume XXX, Number 1, January/February 2010

Link: Secure World Foundation Press Release ("Defending Planet Earth: Special Publication Details Asteroid, Comet Threat," 30 March 2010

Link: The Planetary Report, Volume XXX, Number 1, January/February 2010 (Location: Secure World Foundation)

Link: Secure World Foundation website blog page post (Defending Planet Earth: Special Publication Details Asteroid, Comet Threat)

Link: The Planetary Report, Volume XXX, Number 1, January/February 2010 ( library)

29 March 2010

Chinese University Paper on Asteroid Mission Design

Paper from the Beijing Institute of Technology and Harbin Institute of Technology on an asteroid mission design. Dr. Ping Yuan Cui of the Beijing Institute of Technology and some of his Chinese colleagues have published previous asteroid mission design papers (see below). This is one of their latest papers.

Target selection and transfer trajectories design for exploring asteroid mission
Journal: SCIENCE CHINA Technological Sciences
Publisher Science China Press, co-published with Springer
ISSN: 1674-7321 (Print) 1869-1900 (Online)
DOI: 10.1007/s11431-010-0007-6
SpringerLink Date: Sunday, March 21, 2010


Ping Yuan Cui(1), Dong Qiao(1), HuTao Cui(2) and EnJie Luan(3)
(1) School of Aerospace Engineering, Beijing Institute of Technology, Beijing, 100081, China
(2) Harbin Institute of Technology, Harbin, 150001, China
(3) National Defense Science and Industry Bureau, Beijing, 100048, China


Technique of target selection and profiles of transfer trajectory for Chinese asteroid exploring mission are studied systemically. A complete set of approaches to selecting mission targets and designing the transfer trajectory is proposed. First, when selecting a target for mission, some factors regarded as the scientific motivations are discussed. Then, when analyzing the accessibility of targets, instead of the classical strategy, the multiple gravity-assist strategy is provided. The suitable and possible targets, taking into account scientific value and technically feasible, are obtained via selection and estimation. When designing the transfer trajectory for exploring asteroid mission, an approach to selecting gravity-assist celestial body is proposed. Finally, according to the mission constraints, the trajectory profile with 2-years ΔV-EGA for exploring asteroid is presented. Through analyzing the trajectory profile, unexpected result that the trajectory would pass by two main-belts asteroids is found. So, the original proposal is extended to the multiple flybys mission. It adds the scientific return for asteroid mission.

Link: Paper (PingYuan Cui, Dong Qiao, HuTao Cui and EnJie Luan, "Target selection and transfer trajectories design for exploring asteroid mission," SCIENCE CHINA Technological Sciences, Sunday, March 21, 2010)

Link: Paper (Rui Xua, Pingyuan Cuib, Dong Qiaob and Enjie Luanc, "Design and optimization of trajectory to Near-Earth asteroid for sample return mission using gravity assists," Advances in Space Research, Volume 40, Issue 2, 2007, Pages 220-225).

Link: Paper (Dong Qiaoa, Hutao Cuib and Pingyuan Cuia, "The design of transfer trajectory for Ivar asteroid exploration mission," Acta Astronautica, Volume 65, Issues 11-12, December 2009, Pages 1553-1560).

WISE and Asteroids: Information for Teachers, Students, and the rest of us

The Hands-On-Universe (HOU) Wise page has more information related to the WISE spacecraft (and its goals to find asteroids) and one of its program to provide outreach to students. This site provides materials for teachers to use to educate students specific to the use of WISE to find asteroids. The information is also generally useful as educational resources for all persons, regardless of age. There are multiple presentations available on WISE as well as a student primer on WISE and asteroid investigations.

Link: WISE Mission Asteroids

Link: WISE presentation

Link: NASA’s WISE Mission and Hands On Universe

Link: Hands-On Universe WISE Workgroup

28 March 2010

Update on Hayabusa Earth Reentry Plan

From Emily Lakdawalla at The Planetary Society Blog...

Hayabusa update: Traverse to night-side approach successful
Mar. 26, 2010 | 09:27 PDT | 16:27 UTC

There's a new update on the JAXA website from Junichiro Kawaguchi indicating that Hayabusa's mission team has successfully shifted the little spacecraft's approach trajectory from the day side to the night side of Earth, a critical maneuver for the survival of the sample return capsule. (There's more detail on this maneuver in my last Hayabusa post.)

Hayabusa's instantaneous trajectory -- that is, the course it would take if the spacecraft died today -- has it approaching within about 13,000 kilometers of Earth's cloud tops. That's one Earth diameter, folks; the long journey is almost over. "The delta-V left is very small, and on 27th, Hayabusa will complete its long ion engine propulsion from last spring," Kawaguchi writes. That's tomorrow! "What is left is a series of trajectory corrections and the project team is finalizing the preparations for them."

Then it'll just be watch and wait until June 13, when the sample return capsule lands in the Australian desert, and the hardworking carrier spacecraft burns up in Earth's atmosphere. Only then will we find out whether the capsule actually contains any grains of dust from asteroid Itokawa. If so, it'll be the first sample return from the surface of any body beyond our own Moon.

Link: The Planetary Society Blog

26 March 2010

Lunar and Planetary Lab's Evening Lecture Series (iTunesU lectures on asteroids and NEOs)

From mpml...

Multiples iTunesU lectures on asteroids and NEO are available from the Lunar and Planetary Laboratory (LPL), Department of Planetary Sciences at the University of Arizona, Evening Lecture Series. Also, there is an upcoming lecture on 21 April 2010 related to NEAs. Here is more information about LPL evening lecture schedule and links to the previous asteroid/NEO podcasts.

Chicken Little’s Reservoir: LPL’s Legacy and Current Advancements in Near-Earth Asteroid Population Detection and Mitigation Efforts
LPL50 Anniversary Alumnus Lecture: Faith Vilas
Wednesday, 21 April 2010

Dr. Faith Vilas, LPL alumna and Director of the Multiple Mirror Telescope Obervatory (MMT), is the scheduled speaker.

The transient population of near-Earth asteroids (NEAs represents the largest fraction of the Solar System objects that can impact the Earth. For the first time in its history, humankind has the capacity to consider how to prevent a catastrophic collision of a near-Earth object with the Earth, and the audacity to imagine that it can do so. In pursuit of this goal, LPL scientists have played a major role in shaping our understanding of the local- to global- catastrophic damage threat to humankind from the impact of Solar System objects on the Earth's surface. The first concerted effort to detect NEAs was pioneered at LPL; telescopic detection and characterization of NEAs, including the first detection of an imminent impactor, 2008 TC3, on its final approach to the Earth, continue at LPL to this day. The scars of earlier encounters of NEAs with the Earth are studied to understand their effects on the planet's history and evolution. Two robotic spacecraft have visited the NEAs 433 Eros and 25143 Itokawa. Large diameter telescopes now actively engage in observational studies of NEAs in order to expand our characterization of these objects. And, in a move to direct further detection and mitigation efforts in the United States (and encourage international efforts), the National Research Council has just released a study on defending planet Earth. I will review past, present, and possible future NEA studies, and LPL's involvement in saving humankind from mass destruction.

- LPL asteroid/NEO related podcasts

- "The Search for Hazardous Asteroids from Mt. Lemmon," Edward Beshore (Catalina Sky Survey, CSS, PI), 56:43, 02 March 2009

Lecture: downloadable podcast (iTunesU)

- "The Science and Exploration of Near-Earth Asteroids," Dante Lauretta, 1:19:33, 18 November 2008

Lecture: downloadable podcast (iTunesU)

- "OSIRIS-REx: NASA Sample Return Mission from a Primitive Asteroid," Dante Lauretta (Deputy PI, OSIRIS-REx), 1:01:24, 30 January 2010

Lecture: downloadable podcast (iTunesU)

- "Scientific Results of NASA's Deep Impact Mission," H. Jay Melosh, 1:15:28, 28 Feb 2008

Lecture: downloadable podcast (iTunesU)

Link: Catalina Sky Survey, Lunar and Planetary Laboratory, University of Arizona

Link: LPL Evening Lecture Series

Article on WISE and Asteroid Hunt

Selections from the article, audio (.mp3) also available...

Our instrument is finding hundreds of asteroids every day that were never detected before," says Ned Wright, principal investigator for WISE and a physicist at the University of California in Los Angeles. "WISE is very good at this kind of work."

Visible-light telescopes conducting past asteroid surveys may have missed a large population of darker asteroids that WISE is now flushing out of hiding. Most of the asteroids WISE is finding are in the main asteroid belt between Mars and Jupiter, but a fraction of them are different—they're the kind of Earth-approaching asteroids that send shivers all the way down a Brontosaurus' spine.

"WISE has only been in orbit for about three months, but we've already found a handful of asteroids classified as 'potentially hazardous,' including one seen in 1996 but lost until re-observed by WISE. To be named 'potentially hazardous,' an asteroid has to pass within about 5 million miles of Earth's orbit. One of our discoveries will cross Earth's orbit less than 700,000 miles away."

WISE tracks each potentially hazardous near-Earth object (NEO) it finds for an average of 30 hours and then produces a "short track" predicting where it will be for the next few weeks. The WISE team sends all of this information to the NASA-funded Minor Planet Center in Boston. They post it on a publicly available NEO confirmation page, where scientists and amateur astronomers alike can continue to track the asteroid.

"WISE actually discovered all five of the NEOs the center was confirming as of March 1st," says Wright.

Many telescopes on Earth are already searching. Notable programs include LINEAR, the Catalina Sky Survey, Spacewatch, NEAT and LONEOS, among others1. Working together over the years they have found more than a thousand potentially hazardous asteroids.

WISE's contribution to the total will be impressive. Between now and late October, when the mission is slated to end, Wright estimates the observatory will find a hundred thousand asteroids, mostly in the main belt, and hundreds of near Earth objects.

Link: Science @ NASA Article (An Avalanche of Dark Asteroids, 26 March 2010)

Link: AUDIO: Science @ NASA Article (An Avalanche of Dark Asteroids, 26 March 2010) - .mp3

25 March 2010

Misc. New Journal Articles: NEO, Resource Law, NEOimpactor (modeling NEO impact consequence), Orion CEV-based Human NEO Mission, OpenOrb (Open-Source Orbital Simulation), NEO IR Observatory Design

Pella vilya: Near earth objects—Planetary defence through the regulation of resource utilisation

Acta Astronautica

Gérardine Meishan Goh (a)
(a) Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Bonn, Germany/Institute of Air and Space Law, University of Cologne, Germany

Reactions to near earth objects (NEOs) in the past decade have run the gamut from expectations of Armageddon-type scenarios to Eureka moments of revolutionary scientific ideas. Concerns over the potentially devastating effects of an unmitigated collision jostle with forecasts of untold economic returns from the utilisation of NEO resources. Drawing from recent analogies and examples from the field of international environmental law, this paper proposes the development of a legal framework for the regulation of NEO resource utilisation. The proposed legal framework also includes a mechanism to ensure the political will and economic investment necessary for technological advances in planetary defence. By twinning the threats and opportunities presented by NEOs, this paper also analyses the position of theme-specific space law development in the overall legal framework of space exploration and traffic management.

Link: Journal Reference

Global vulnerability to near-Earth object impact

Risk Management (2010) 12, 31–53.

Nicholas J Bailey(a), Graham G Swinerd(a), Hugh G Lewis(a) and Richard Crowther(b)
1. (a)Astronautics Research Group, School of Engineering Sciences, University of Southampton, Southampton SO17 1BJ, UK. 2. (b)Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxon, OX11 0QX, UK

A clear appreciation of the consequences resulting from an asteroid impact is required in order to understand the near-Earth object (NEO) hazard. Three main processes require modelling to analyse the entire impact event. These are the atmospheric entry phase, land impact events and ocean impact events. A range of impact generated effects (IGEs) are produced by different impact scenarios. It is these IGEs that present the threat to human populations worldwide, and the infrastructure they utilise. A software system for analysing the NEO threat has been developed, entitled NEOimpactor, to examine the social and economic consequences from land and ocean impacts. Existing mathematical models for the three principal impact processes have been integrated into one complete system, which has the capability to model the various effects of a terrestrial asteroid impact and, critically, predict the consequences for the global population and infrastructure. Analysis of multiple impact simulations provides a robust method for the provision of an integrated, global vulnerability assessment of the NEO hazard. The primary graphical outputs from NEOimpactor are in the form of ‘relative consequence’ maps, and these have been designed to be comprehensible to a non-specialist audience. By the use of a series of multiple-impact simulations, the system has identified the five countries most at risk from the impact hazard, as well as indicating the various factors influencing vulnerability.

Link: Journal Article

Scientific exploration of near-Earth objects via the Orion Crew Exploration Vehicle

Meteoritics & Planetary Science
Volume 44 Issue 12, Pages 1825 - 1836
Published Online: 26 Feb 2010

Paul A. Abell(1, 2, *,) David J. Korsmeyer(3), Rob R. Landis(3), Thomas D. Jones(4), Daniel R. Adamo(5), David D. Morrison(6), Lawrence G. Lemke(7), Andrew A. Gonzales(7), Robert Gershman(8), Theodore H. Sweetser(8), Lindley L. Johnson(9) and Ed Lu(10)
1Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston, Texas 77058, USA 2Planetary Science Institute, 1700 E. Fort Lowell, Tucson, Arizona 85719, USA 3Intelligent Systems Division, NASA Ames Research Center, Moffett Field, California 94035, USA 4Association of Space Explorers, 1150 Gemini Avenue, Houston, Texas 77058, USA 5Trajectory Consultant, 4203 Moonlight Shadow Court, Houston, Texas 77059, USA 6NASA Astrobiology Institute, NASA Ames Research Center, Moffett Field, California 94035, USA 7NASA Ames Research Center, Moffett Field, California 94035, USA 8Jet Propulsion Laboratory, Pasadena, California 91109, USA 9Planetary Science Division, NASA Headquarters, Washington, D.C. 20546, USA 10Google Inc., 1600 Amphitheatre Parkway, Mountain View, California 94043, USA

Abstract—A study in late 2006 was sponsored by the Advanced Projects Office within NASA's Constellation Program to examine the feasibility of sending the Orion Crew Exploration Vehicle (CEV) to a near-Earth object (NEO). The ideal mission profile would involve two or three astronauts on a 90 to 180 day flight, which would include a 7 to 14 day stay for proximity operations at the target NEO. This mission would be the first human expedition to an interplanetary body beyond the Earth-Moon system and would prove useful for testing technologies required for human missions to Mars and other solar system destinations. Piloted missions to NEOs using the CEV would undoubtedly provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific investigations of these primitive objects. The main scientific advantage of sending piloted missions to NEOs would be the flexibility of the crew to perform tasks and to adapt to situations in real time. A crewed vehicle would be able to test several different sample collection techniques and target specific areas of interest via extra-vehicular activities (EVAs) more efficiently than robotic spacecraft. Such capabilities greatly enhance the scientific return from these missions to NEOs, destinations vital to understanding the evolution and thermal histories of primitive bodies during the formation of the early solar system. Data collected from these missions would help constrain the suite of materials possibly delivered to the early Earth, and would identify potential source regions from which NEOs originate. In addition, the resulting scientific investigations would refine designs for future extraterrestrial resource extraction and utilization, and assist in the development of hazard mitigation techniques for planetary defense.

Link: Journal Article

OpenOrb: Open-source asteroid orbit computation software including statistical ranging

Meteoritics & Planetary Science
Volume 44 Issue 12, Pages 1853 - 1861
Published Online: 26 Feb 2010

Mikael Granvik(1, 1), Jenni Virtanen(2), *, Dagmara Oszkiewicz(3) and Karri Muinonen(4) 1Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Drive, Honolulu, Hawai'i 96822, USA 2Finnish Geodetic Institute, P.O. Box 15, 02431 Masala, Finland 3Observatory, P.O. Box 14, 00014 University of Helsinki, Finland 4Observatory, P.O. Box 14, 00014 University of Helsinki, Finland, Finnish Geodetic Institute, P.O. Box 15, 02431 Masala, Finland

We are making an open-source asteroid orbit computation software package called OpenOrb publicly available. OpenOrb is built on a well-established Bayesian inversion theory, which means that it is to a large part complementary to orbit-computation packages currently available. In particular, OpenOrb is the first package that contains tools for rigorously estimating the uncertainties resulting from the inverse problem of computing orbital elements using scarce astrometry. In addition to the well-known least-squares method, OpenOrb also contains both Monte-Carlo (MC) and Markov-Chain MC (MCMC; Oszkiewicz et al. [2009]) versions of the statistical ranging method. Ranging allows the user to obtain sampled, non-Gaussian orbital-element probability-density functions and is therefore optimized for cases where the amount of astrometry is scarce or spans a relatively short time interval. Ranging-based methods have successfully been applied to a variety of different problems such as rigorous ephemeris prediction, orbital element distribution studies for transneptunian objects, the computation of invariant collision probabilities between near-Earth objects and the Earth, detection of linkages between astrometric asteroid observations within an apparition as well as between apparitions, and in the rigorous analysis of the impact of orbital arc length and/or astrometric uncertainty on the uncertainty of the resulting orbits. Tools for making ephemeris predictions and for classifying objects based on their orbits are also available in OpenOrb. As an example, we use OpenOrb in the search for candidate retrograde and/or high-inclination objects similar to 2008 KV42 in the known population of transneptunian objects that have an observational time span shorter than 30 days.

Link: Journal Article

NEO Survey: An Efficient Search for Near-Earth Objects by an IR Observatory in a Venus-like Orbit

AIP Conf. Proc. -- January 28, 2010 -- Volume 1208, pp. 418-429


Robert Arentz,(a) Harold Reitsema,(a) Jeffrey Van Cleve,(b) and Roger Linfield(a)
aBall Aerospace & Technologies Corp., 1600 Commerce St., Boulder, CO 80301
bSETI Institute, NASA Ames Research Center, NS 244-30, Room 107G, Moffett Field, CA 94035

In 2003 NASA commissioned a Science Definition Team (SDT) (Stokes, et al., 2003) to study the threats posed by Near-Earth Objects (NEOs), recommend efficient methods for detecting NEOs down to 140 meters in diameter, and suggest conceptual mitigation techniques. In this same time frame, Congress set the goal of cataloguing 90% of all NEOs down to 140 meters diameter by 2020. The SDT concluded that the infrared passband from ~5 to ~11 microns is the best for finding NEOs; that an aperture of 50 centimeters is sufficient; and that locating a NEO-finding observatory in a Venus-like orbit is ideal. Since then, NASA and its industrial partners (such as Ball Aerospace) have flown two very NEO-relevant deep-space missions—the Spitzer Space Telescope and Kepler. Herein, a high-reliability, credibly-costed design is presented based on Spitzer and Kepler that meets the 90%/140-m/2020 requirements for about $600 M. This design will also detect about 85% of all >100 meter NEOs, about 70% of all >65 meter NEOs, and about 50% of all >50 meter NEOs. These smaller NEOs constitute a newly recognized threat regime that cannot be efficiently found from the ground.

Link: Journal Article

Planetary Society Article on the Hunt for An Asteroid Impact Site

From the article by The Planetary Society...

The Vichada River snakes slowly through the thick foliage of the Colombian jungle. It twists and turns through the marshy plains, never deviating from its constant western course. Only in one place, at the center of Vichada province in Eastern Colombia, does the river vary from its westward flow: there it shifts suddenly southward and for dozens of kilometers follows the arc of a near-perfect semi-circle. Finally, it straitens out and resumes its normal flow on its way to join with the mighty Orinoco.

It was January of 2004 when the elegant curve of the Vichada first caught the attention of geologist Max Rocca of Buenos Aires. Rocca at the time was searching for traces of ancient asteroid impacts in South America, a task made exceptionally challenging by the jungle growth that covers much of the continent and obscures the outlines of mountains and depressions. While pouring over images from the Landsat 5 satellite, which were posted on the website of NASA’s John Stennis space center, Rocca noticed the circular arc of the Vichada River. This, he realized, might be a clue: Perfect geometrical contours are rare in nature, and the presence of such a curve on the Vichada was suggestive. Could it be that the course of the river was shaped by the circular outlines of an impact crater? Rocca decided to find out.
More On This Project

Max Rocca is not a traditional geologist. He is not employed by a university department, and his work is not sponsored by any government agency or mining and drilling company. The 43 year-old Argentinian is a private citizen who makes his living as a systems analyst, and although it has been years since his days as a student of geology at the University of Buenos Aires, his fascination with the structure of the Earth never waned. In 2002 he applied for a grant from The Planetary Society to help him search for impact craters in the jungle-covered terrain of South American. To us at the Society he seemed like a perfect candidate – an amateur with the skills of a professional, someone who will make the best use of the resources we can provide. We quickly granted his request, and have been funding his work continuously for the past 8 years. Rocca, for his part, did not disappoint, and has been producing a steady stream of discoveries ever since.

Rocca specializes in the study of satellite images and aerial photographs of remote regions, and time and again he has demonstrated his remarkable talent for seeing what others cannot. In 2007, for example, in Patagonia in central Argentina, he located the largest impact crater field in the Southern Hemisphere. Known as Bajada del Diablo, the field was originally detected in 1987 by Hugo Corbella, and contains more than 100 craters ranging from 100 to 500 meters in diameter. Rocca then joined forces with a group of geologists from Argentinian research centers who travelled to the region, and in 2009 they jointly published a paper about the crater field in the journal Geomorphology. Along with team member Rogelio Acevedo of the Southern Center for Scientific Research (CADIC) in Tierra del Fuego, Rocca is now working to produce a complete catalog of South American impact craters.

Link: Planetary Society Researcher Discovers Largest Crater in South America

Article on Arecibo Funding Issues for NEO Radar Research

Selection from the article...

Radar measurements set to be made in January 2013 by the Arecibo Observatory in Puerto Rico, US, could help rule out an impact by asteroid Apophis.

But the cuts mean Arecibo needs an extra $2m-$3m a year to continue.

If not, the observations planned for 2011-2013 will have to be abandoned, the facility's director told BBC News.

Dr Michael Nolan said he was "moderately optimistic" that the money could be found.

Although asteroid 99942 Apophis is one of the most hazardous Neos today, the calculated probability of an impact is small.

Last year, the US space agency (Nasa) lowered the chances of an impact on 13 April 2036 from one in 45,000 to one in 250,000.

The 300m-wide asteroid raised concerns in December 2004, when initial observations indicated a probability of up to 2.7% that it would strike Earth in 2029.

Additional measurements ruled out this possibility, but on 13 April 2029, Apophis will approach Earth at a distance no closer than 29,470 km (18,300 miles).

But the US National Science Foundation (NSF), which operates the facility, has indicated it will substantially cut funding starting from 2011, when the telescope will receive an overall budget of $9m.

In its latest budget request, Nasa has set aside money both for Arecibo and for research on Neos like Apophis. If the space agency picked up the difference - estimated to be on the order of $2m-$3m per year - the project would be able to continue.

In 2011, Apophis will start to become visible again to optical telescopes and it will make a relatively close flyby in January 2013 - passing by Earth at a distance of 13 million kilometres - which would enable measurements by Arecibo's radar.

"Cuts cast doubt on asteroid plan"
Paul Rincon
Science Reporter, BBC News
25 March 2010

Link: BBC News Article

24 March 2010

Update on NASA FY2011 budget and NEO funding: Near Earth Object Observation (NEOO) Initiative

As you may recall when the NASA FY2011 Budget was released there seemed to be an increase in the funding for NEO specific work, from the approximately US$4M to about US$16M. Here is more detail.

From the NASA FY2011 Science Mission Directorate budget overview document...
The Near Earth Object Observations (NEOO) project has been augmented by $16M/year, to accelerate progress on the detection and characterization of NEOs less than 1km in diameter. In FY 2011, this will support the analysis of archived data from the Wide-Field Infrared Spectroscopic Explorer (WISE) mission.

A presentation from Dr. Wes Huntress has more detail on some of the allocation of this funding. Highlights from the presentation, specifically dealing with NEOs... 

- NASA Current Funded Systems (existing funding):
- NEO Program Office @ JPL (Program coordination, Automated SENTRY)
- Minor Planet Center (MPC) (IAU sanctioned, Discovery Clearinghouse, Initial Orbit Determination)
- Observation: NEO-WISE, LINEAR, Catalina Sky Survey, Pan-STARRS

- Near Earth Object Observation (NEOO) Initiative (new funding):
With the additional funding of $16M, the NEOO Program will:
- Extend the collection, archive, and analysis of WISE NEO data
- Enable collection of NEO data by the USAF’s Pan-STARRS project
- Support the continued operation of planetary radar capabilities at the NSF’s Arecibo and NASA’s own Goldstone facilities
- Investigate use of both ground and space-based assets for Potentially Hazardous Objects (PHOs) 140 meters and below
- Determinate what characteristics of PHOs are needed to assess possible mitigation actions

Link: Dr. Wes Huntress Science Committee Report

Link: NASA FY2011 Science Mission Directorate Budget Overview Document

23 March 2010

Dr. Christie Maddock's Doctoral Thesis on Mirror Bees Asteroid Mitigation Concept: "On the dynamics, navigation and control of a spacecraft formation of solar concentrators in the proximity of an asteroid"

Dr. Christie Maddock recently completed her doctoral thesis at the University of Glasgow Department of Aerospace Engineering (Space Advanced Research Team) on the dynamics and navigation of the "Mirror Bees" asteroid mitigation concept (solar concentrators around an asteroid). The thesis is now available online (Advisors: Dr. Gianmarco Radice, Dr. Massimiliano Vasile).

Video of Dr. Maddock discussing the Mirror Bees Concept (from 2009)
Encounter 2029 - Glasgow 1/2 - NEO deflection trough a multi-mirror system (part 1 of 2)

"On the dynamics, navigation and control of a spacecraft formation of solar concentrators in the proximity of an asteroid"

Maddock, Christie Alisa
PhD thesis
University of Glasgow


This purpose of this dissertation is to ascertain whether solar sublimation is a viable method for the deflection of a Near Earth Asteroid. From a research view point, the methods and analysis are applicable to proximal motion around a celestial body, in particular one with a non-Keplerian or irregular orbit as in the case here with the orbit being constantly altered by the deflection action and subject to perturbations, such as solar radiation pressure. Two concepts, and the corresponding dynamics and control, are presented based on previous trade-off and optimisation studies. The first uses a paraboloidic reflector to concentrate the solar radiation onto a solar-pumped laser, which is then directed onto a specific spot on the NEO by a small directional mirror. The spacecraft orbits are designed to fly in formation with the asteroid around the Sun, and are based on the orbital element differences. The formation orbits were optimised based on a number of single and multiple objective functions. A feedback control law is presented for the orbital maintenance required to counteract the solar radiation pressure (due primarily to the large surface area of the primary reflector), and the third-body effects due to the gravitational field of the asteroid. The second option takes advantage of the balance between the gravity attraction of the NEO and solar pressure acting on the collector. The mirror focuses the light directly onto the asteroid surface, controlling the beam by adjusting the focal point of the primary reflector. By altering the shape of the mirror surface, both the focal point and the vector of the solar radiation pressure can be manipulated. An interesting navigation strategy is proposed based on the attitude measurements, the inertial position of each spacecraft, the intersatellite position and velocity measurements, and a 2D image from a rotating onboard camera. The navigational data is used for both the orbital control of the spacecraft and for the beam pointing. The results of simulations of a hypothetical deflection mission of the asteroid Apophis are presented for the dynamics, control, attitude and navigation, accounting for solar radiation pressure, the gravity field of the asteroid, and the deviation of the NEO orbit. The results show that both concepts provide the required deflection with a feasible mass at launch, solving most of the issues related to the solar sublimation method. One of the critical aspects of this deflection concept is properly placing the concentrators in the proximity of the asteroid in order to avoid the plume impingement and the occultation from the asteroid itself. Issues regarding the contamination of the mirrors are addressed and compared with the simulated deflections predicted considering no contamination. Lastly, initial system mass budgets are presented.

Link: University of Glasgow Thesis Page

Link: Thesis: Maddock, Christie Alisa (2010) On the dynamics, navigation and control of a spacecraft formation of solar concentrators in the proximity of an asteroid. PhD thesis, University of Glasgow

Link: Biography at the University of Glasgow: Dr. Maddock

DLR AsteroidFinder Project

From a DLR document:

The German Aerospace Center (DLR) is pursuing a program of space-mission development based on a standard satellite bus (SSB), suitable for missions and applications of different types. This project has the strategic objective of establishing within DLR the capabilities and facilities necessary for satellite development and operations.

Our proposed mission, AsteroidFinder, was selected as the first mission to use the SSB. The primary goal of the mission is to search for Inner-Earth Objects (IEOs), a particular class of Earth-approaching asteroids with orbits lying completely within the Earth’s orbit. Due to their proximity on the sky to the Sun, IEOs are extremely difficult to discover from the ground. By the end of September nearly 5700 Near Earth Objects (NEOs) have been discovered, of which only 9 are IEOs. Simulations have shown that AsteroidFinder may detect some dozens of IEOs in an operational period of two years and be able to characterize the population in terms of total number, orbit and size distribution.

A secondary goal of the mission is to demonstrate that the detection of cm-sized space debris is in principle feasible with a satellite-based optical instrument. To achieve its goals the mission has to detect small objects of various surface albedos, including extremely dark ones, near the direction of the Sun. This requires a limiting sensitivity of > 18.5 mag. Long exposure times (~ 1 min) and, therefore, a high pointing stability rate (~ 1 arcsec/s) are needed. Since this requirement is beyond the capability of the bus an order- of-magnitude improvement must be achieved at payload level. Stray light from the Sun, Earth and other objects must be effectively suppressed. The baseline payload of the AsteroidFinder mission consists of two main elements: the telescope and the electronic unit (EU). The EU contains the focal-plane array (detector), the corresponding front-end electronics, the digital-processing unit and power-supply unit. The data produced in the EU are stored in the mass memory of the satellite. The thermal control and telemetry are provided by the spacecraft bus. In 2008 a Phase-A study, in which several DLR institutes participated, successfully confirmed the feasibility of the project. Scientists in our Department were responsible for payload project management, for the scientific background of the mission, the definition of the scientific requirements, and for the observation strategy

Link: DLR Department: “ASTEROIDS and COMETS” XI. Report 2008

Selections from the article...

Plans for the satellite -- which according to its builder, will be 80 centimeters wide and deep and 100 centimeters high, as big as a small refrigerator -- are slowly taking shape in Bremen. The plan is to have the satellite operational by 2013.

Work on the asteroid project is expected to last three more years. The pressure on the scientists behind the satellite will be huge if it flops. But nobody wants to think about that. Specifications for the satellite's individual components are expected to be completed by the end of the year, but there is still plenty of work to do. Afterwards, AstroidFinder will be built and then tested under the strenuous conditions it would undergo in outer space: It will be shaken, frozen and irradiated.

It is still unclear how AstroidFinder will be delivered to its orbit, between 650 and 850 kilometers above the Earth. DLR can either piggy back on another space mission or go the far more expensive route and purchase its own rocket. But that might be a small price to pay for a satellite that could help defend the planet from the deadly impact of an asteroid. Earth already bears scars -- in the form of craters -- all over its surface from previous asteroid assaults. And it would be prudent if we were able to predict the next impact before it happens.

"Asteroid Early Warning System: German Satellite to Help Detect Threats to Earth"
Christoph Seidler in Bremen
Der Spiegel
19 March 2010

Link: Der Speigel Article

Post Explosion Reformulation of Asteroid Fragments: Results from New Simulations

From NewScientist Article...

If a sizeable asteroid is found heading towards Earth, one option is to nuke it. But too small a bomb would cause the fragments to fly apart only slowly, allowing them to clump together under their mutual gravity. Simulations now show this can happen in an alarmingly short time.

Don Korycansky of the University of California, Santa Cruz, and Catherine Plesko of the Los Alamos National Laboratory in New Mexico simulated blowing up asteroids 1 kilometre across. When the speed of dispersal was relatively low, it took only hours for the fragments to coalesce into a new rock.

"The high-speed stuff goes away but the low-speed stuff reassembles [in] 2 to 18 hours," Korycansky says. The simulations were presented (pdf) last week at the Lunar and Planetary Science Conference in Houston, Texas.

Reassuringly, a 2009 study led by David Dearborn of the Lawrence Livermore National Laboratory in California showed that a 900-kiloton nuclear device – which is within our capability – would permanently disperse a 1-kilometre asteroid.

Link: NewScientist Article ("'Terminator' asteroids could re-form after nuke"

From LPI Abstract:

Asteroids and comets range in composition from rubble piles to delicate conglomerations of ice and rock to solid objects. They are occasionally found on trajectories that pose an impact hazard to the Earth. There is an ongoing scientific debate about how to best mitigate the risk posed by these potentially hazardous objects (PHOs). Several of the techniques proposed involve applying shortduration impulses to a PHO in order to change its orbit, by means of standoff blasts, surface detonations, or kinetic impacts. However, such methods have the potential to knock fragments off the parent body or disrupt it completely. The resulting fragments may continue to threaten ground or orbital assets if they have not been dispersed far enough on diverging trajectories, or collectively deflected away from the original Earth intercepting trajectory to a sufficient degree. Here we explore the question of the time required after an impulse for fragments to reaggregate or disperse to large radii.

Link: LPI Abstract (REAGGREGATION TIMESOF POTENTIALLYHAZARDOUS OBJECT FRAGMENTSAFTER A HAZARD MITIGATION IMPULSE. D. G. Korycansky, CODEP, Department of Earth and Planetary Sciences, University of California, Santa Cruz CA 95064 (, C. S. Plesko, Los Alamos National Laboratory Applied Physics Division.)

New Evidence and Analysis for Chicxulub and the Evidence for a Dinosaur-Killing Impact

Link: Science Magazine Article ("The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary"): Science 5 March 2010: Vol. 327. no. 5970, pp. 1214 - 1218

The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary

Peter Schulte,1,* Laia Alegret,2 Ignacio Arenillas,2 José A. Arz,2 Penny J. Barton,3 Paul R. Bown,4 Timothy J. Bralower,5 Gail L. Christeson,6 Philippe Claeys,7 Charles S. Cockell,8 Gareth S. Collins,9 Alexander Deutsch,10 Tamara J. Goldin,11 Kazuhisa Goto,12 José M. Grajales-Nishimura,13 Richard A. F. Grieve,14 Sean P. S. Gulick,6 Kirk R. Johnson,15 Wolfgang Kiessling,16 Christian Koeberl,11 David A. Kring,17 Kenneth G. MacLeod,18 Takafumi Matsui,19 Jay Melosh,20 Alessandro Montanari,21 Joanna V. Morgan,9 Clive R. Neal,22 Douglas J. Nichols,15 Richard D. Norris,23 Elisabetta Pierazzo,24 Greg Ravizza,25 Mario Rebolledo-Vieyra,26 Wolf Uwe Reimold,16 Eric Robin,27 Tobias Salge,28 Robert P. Speijer,29 Arthur R. Sweet,30 Jaime Urrutia-Fucugauchi,31 Vivi Vajda,32 Michael T. Whalen,33 Pi S. Willumsen32

The Cretaceous-Paleogene boundary ~65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction. Notably, a single ejecta-rich deposit compositionally linked to the Chicxulub impact is globally distributed at the Cretaceous-Paleogene boundary. The temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations (for example, darkness and cooling) lead us to conclude that the Chicxulub impact triggered the mass extinction.

1 GeoZentrum Nordbayern, Universität Erlangen-Nürnberg, Schlossgarten 5, D-91054 Erlangen, Germany.
2 Departamento de Ciencias de la Tierra e Instituto Universitario de Investigación de Ciencias Ambientales de Aragón, Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain.
3 Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK.
4 Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK.
5 Department of Geosciences, Pennsylvania State University, University Park, PA 16802, USA.
6 Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, J.J. Pickle Research Campus, 10100 Burnet Road 196-ROC, Austin, TX 78759, USA.
7 Earth System Science, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
8 Centre for Earth, Planetary, Space and Astronomical Research, Open University, Milton Keynes MK7 6AA, UK.
9 Earth Science and Engineering, Imperial College London, London SW7 2BP, UK.
10 Institut für Planetologie, Universität Münster, D-48149 Münster, Germany.
11 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
12 Tsunami Engineering Laboratory, Disaster Control Research Center, Graduate School of Engineering, Tohoku University, 6-6-11-1106 Aoba, Aramaki, Sendai 980-8579, Japan.
13 Programa de Geología de Exploracíon y Explotacíon, Dirección de Investigación y Posgrado, Instituto Mexicano del Petróleo, Eje Lázaro Cárdenas No. 152, C.P. 07730, México City, México.
14 Earth Sciences Sector, Natural Resources Canada, Ottawa, Ontario K1A 0E4, Canada.
15 Research and Collections Division, Denver Museum of Nature and Science, 2001 Colorado Boulevard, Denver, CO 80205, USA.
16 Museum für Naturkunde, Leibniz Institute at the Humboldt University Berlin, Invalidenstrasse 43, D-10115 Berlin, Germany.
17 Center for Lunar Science and Exploration, Universities Space Research Association–Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058–1113, USA.
18 Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA.
19 Planetary Exploration Research Center, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan.
20 Earth and Atmospheric Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907–2051, USA.
21 Osservatorio Geologico di Coldigioco, 62021 Apiro (MC), Italy.
22 Department of Civil Engineering and Geological Sciences, 156 Fitzpatrick Hall, University of Notre Dame, Notre Dame, IN 46556, USA.
23 SIO Geological Collections, 301 Vaughan Hall, MS-0244, Scripps Institution of Oceanography, La Jolla, CA 92093–0244, USA.
24 Planetary Science Institute, 1700 East Fort Lowell Road, Suite 106, Tucson, AZ 85719, USA.
25 Department of Geology and Geophysics, School of Ocean and Earth Science and Technology, University of Hawaii, Manoa, Honolulu, HI 96822, USA.
26 Unidad de Ciencias del Agua, Centro de Investigación Científica de Yucatán, A.C., Calle 8, No. 39, Mz. 29, S.M. 64, Cancún, Quintana Roo, 77500, México.
27 Laboratoire des Sciences du Climat et de l’Environnement, Institut Pierre et Simon Laplace, Commission à l’Énergie Atomique/CNRS/Université de Versailles Saint Quentin en Yveunes–UMR 1572, Avenue de la Terrasse, F-91198 Gif-sur-Yvette Cedex, France.
28 Bruker Nano GmbH, Schwarzschildstraße 12, D-12489 Berlin, Germany.
29 Department of Earth and Environmental Sciences, K.U.Leuven, Box 2408, Celestijnenlaan 200E, 3001 Leuven, Belgium.
30 Natural Resources Canada, Geological Survey of Canada Calgary, 3303 33rd Street NW, Calgary, AB T2L 2A7, Canada.
31 Laboratorio de Paleomagnetismo y Paleoambientes, Programa Universitario de Perforaciones en Oceanos y Continentes, Instituto de Geofísica, Universidad Nacional Autónoma de México (UNAM), DF 04510 Mexico, Mexico.
32 Department of Earth and Ecosystem Sciences, Lund University, Sölvegatan 12, 223 62 Lund, Sweden.
33 Department of Geology and Geophysics, University of Alaska, Fairbanks, AK 99775, USA.

From NSF Press Release...

For decades, scientists have accumulated ever-larger datasets that suggest an enormous space rock crashed into the ocean off the Yucatan Peninsula more than 65 million years ago, resulting in the Cretaceous-Paleogene (K-Pg) extinction.

Recent research, supported in part by the National Science Foundation (NSF), suggested that the impact could have occurred 300,000 years prior to the K-Pg extinction, and that another cause--perhaps a second impact, or the long-lasting volcanic activity at the Deccan Traps in what is now India--drove numerous plant and animal species to their end.

Now, an interdisciplinary team of 41 scientists from 12 nations, also supported in part by NSF, has prepared a paper to specifically counter the volcanic and dual-impact alternatives, a comprehensive review of the multiple, global lines of evidence linking a single impact near what is now Chicxulub, Mexico, to the timing and breadth of the K-Pg extinction.

The researchers, led by Peter Schulte of the University of Erlangen-Nuremburg, present their findings in the March 5, 2010, issue of Science.

"We felt it important to present the wealth of data now available about the remarkable and exact correlation between the impact in the Yucatan and the extinction event at the K-Pg boundary," said University of Texas geophysicist Sean Gulick, one of the authors on the paper.

One factor that is not in dispute: the end of the Cretaceous 65.5 million years ago was marked by one of the most devastating extinctions our planet has faced. The most famous victims were the dinosaurs (their avian relatives notwithstanding), but the event also saw the loss of all flying reptiles, most marine reptiles, more than half of land plants and insects, and hosts of other terrestrial and marine organisms--50 to 70 percent of all species on Earth.

As with all mass extinctions, paleontologists have long asked why so many organisms disappeared so quickly. The cause, or causes, would have to influence a large swath of the planet, on land and sea, and would have to reflect observations in the geological record.

As referenced in the new Science paper, one of the key arguments for impact is a well-studied clay layer that appears at K-Pg boundary sites across the globe, usually in association with melt-glass remnants, shocked minerals, and other materials generated by impacts. The authors point out that the layer thickness and the abundance of impact materials both increase systematically with proximity to the Chicxulub crater.

Until 1980, none of the K-Pg boundary sites was linked to an impact. It was not until physicist Luis Alvarez and his son, geologist Walter Alvarez, took a closer look at a thin and unusual clay layer at K-Pg boundary sediments in Italy that the researchers realized the source might be extraterrestrial.

Within the layer--which the current paper now references to at least 350 sites around the world--the researchers found high levels of iridium. The heavy element is not normally found in high concentrations at Earth's surface, but it is highly concentrated in undifferentiated solar system material, like asteroids and comets.

Since that initial discovery, further studies by a number of teams--some of which are represented in the Science paper--uncovered more impact evidence within the clay, including the spherules of altered melt-glass and impact-shocked minerals.

"This clay layer--with evidence for it being impact in origin--is found at every well-preserved K-Pg boundary site in the world, showing a truly global event," added Gulick.

Additional studies, both in the field and in laboratory simulations and models, led to a growing consensus in support of the impact hypothesis. As it currently stands, the extinction resulted from the collision of a space rock roughly 10 kilometers in diameter into carbon- and sulfur-rich rocks beneath what is now Chicxulub, Mexico, yielding a crater that is more than 180 kilometers in diameter; regional tsunami, earthquakes and fires; extended (but not total) darkness; cooling temperatures and acid rain.

"The impact event triggered tsunami many times the size of the wave that hit the Indian Ocean on Dec. 26, 2004," said marine geologist Tim Bralower of Penn State University, another of the paper's authors. "These waves caused massive destruction on the sea floor, with the multiple sediment layers representing the deposition of impact-derived material, mixed with sand and silt, by waves and currents over periods of days after the impact. As the energy levels gradually decreased, the materials settling down gradually became finer."

In some sites close to the impact, around the Gulf of Mexico and the Caribbean, there are two spherule-bearing layers, at times separated by sediment a few meters thick, and some of the recent controversy stems from this apparent duality. The lower layer consists of coarser particles including spherules and shocked minerals, and the upper layer consists of finer particles and has a higher iridium content.

"Reports of multiple horizons with elevated iridium concentrations fairly close to the Chicxulub crater have led to a lot of confusion, and suggestions of multiple impacts," said fellow author Greg Ravizza, a marine and environmental geologist at the University of Hawaii at Manoa. "A key point that cannot be ignored is that data from several sites far away from the Chicxulub crater provide no evidence of multiple large impacts. This observation lends very strong support to the careful stratigraphic synthesis in our paper demonstrating the very complex, and frequently disturbed, character of the sections closest to the Chicxulub crater."

The authors close their paper by discussing the speed and scale with which the impact affected living systems, particularly in relation to the speed and scale of volcanic activity.

An impact the size of the Chicxulub event would release large amounts of water, dust and gasses into the atmosphere, temporarily changing climate. While dust alone would not have been able to cause a global winter, tiny carbonate particulates and soot may have amplified the impact's cooling effects.

An estimated 100-500 gigatons of sulfur was also released, contributing to devastating acid rains on land and in the oceans, and producing sunlight-absorbing sulfur aerosols that may have further cooled the Earth for several years.

Because deep ocean temperatures were largely unaffected, the researchers suggest that the climate recovered relatively rapidly. Such a brief transition is in contrast to the centuries-long influx of material into the atmosphere that would result from volcanic activity. Despite the enormity of the Deccan Traps volcanism, sulfur release, for example, might not surpass one half of a gigaton in a year.

At the slower pace of volcanism, organisms would have more time to react, and climatic changes may have approached 2 degrees Celsius of warming, as opposed to cooling.

"The Chicxulub impact was an extremely rapid perturbation of the Earth's ecosystems, at a scale greater than that of any single volcanic event at the time, or of any other impact known since life became prevalent on Earth," added Gulick. "The rate of change and scale of the effects were clearly the cause of the mass extinction at the end of the Cretaceous."

Additionally, the boundary between the end of the Cretaceous and the start of the Paleogene is marked by clear changes in the plants and animals that existed, a change that is not gradual. Species across the globe showed either extinction or major changes in abundance.

Darkness would have severely affected photosynthesis for ocean micro-organisms, eliminating the base for numerous food chains. As a result, the geologic record shows preferential extinction of organisms in food chains relying on plankton as a food source, and preferential survival for organisms in food-chains relying on a foundation of detritus and decayed matter. Many of the organisms that survived were also smaller, indicating survival was dependent on the ability to subsist on limited resources.

"As with the ocean, land-based ecosystems showed the same pattern of greater impact on food chains dependent on live plants," said paleobotanist Kirk Johnson of the Denver Museum of Nature & Science, another author on the paper. "All large, land animals perished. The survivors included groups of animals who either lived in rivers, streams, and lakes or who were small or lived in burrows. Forests were destroyed globally and the earliest Paleogene landscape was covered by ferns, a type of plant that can grow directly from spores--as opposed to conifers and flowering plants that require pollen to interact with a living plant for reproduction."

Across ecosystems, the Paleogene also marks a rapid radiation of new species filling in empty ecological niches, a process that would be unlikely following a more gradual extinction. Such biological evidence, the authors assert, matches best to an impact scenario, corroborating the evidence from the geologic record.

"I think it is likely that Deccan volcanism did have a global effect on Earth's climate, but several hundred thousand years before the end Cretaceous mass extinction," added Ravizza. "Clear evidence demonstrating massive volcanism right at the mass extinction horizon is lacking. While it may be tempting to make this connection, existing data constraining the timing and duration of volcanism just don't support the idea."

According to the authors, no alternative theory yet proposed addresses the global distribution of evidence for the Cretaceous-Paleogene extinction, nor does any other theory clearly present mechanisms that could have led to such abrupt and complete biotic changes.

"The precise correlation of this huge impact crater with a worldwide layer of impact debris--one that lies directly above the extinction level of both marine and land animals and plants--is one of the most phenomenal discoveries in Earth history," said Johnson. "The science is complex, but the story is simple: a single asteroid impact caused global extinctions at the K-Pg boundary."

H. Richard Lane, program director within the Earth Sciences Division at NSF has helped support the work of both research teams. "This ongoing exchange between two groups of scientists has fostered spirited community dialogue around an issue that is riveting to an engaged public," added Lane. "It feeds the appetite of a science-starved audience, and can only benefit science as a whole, while improving the public's understanding of how science progresses."

Link: National Science Foundation (NSF) Press Release

22 March 2010

International Asteroid Search Campaign

This is a public outreach campaign, called the International Asteroid Search Campaign which has 7 participating countries located on 4 continents as participants. This campaign, called the NASA WISE Asteroid Search Campaign is "part of the public outreach program for the Wide-field Infrared Survey Explorer mission launched in December 2009." From the one of Galileo Teacher Training Program site in regards to the campaign...

The International Asteroid Search Campaign (IASC) is a program for high school and college students who search just hours-old astronomical images for original discoveries. These discoveries include Main Belt asteroids and near-Earth objects (NEOs). Students download the images on a daily basis, perform the analysis with provided software tools, and report their discoveries, which ultimately are recognized by the Minor Planet Center (MPC; Harvard University) and the International Astronomical Union (IAU).

This program is brought to schools at no cost for either participation or the software as an educational service provided by the Astronomical Research Institute (ARI; Charleston, IL), Hardin-Simmons University (HSU; Abilene, TX), Global Hands-On Universe Association (Portugal), and Lawrence Hall of Science (University of California, Berkeley). The software is provided by Astrometrica (Austria).

During times of Moon-less skies, the ARI takes images along the ecliptic using its 0.61-m and 0.81-m telescopes. The following morning these images are prepared and made available to the participating schools. The schools go to Hardin-Simmons University web site ( where they download the images and use the software package Astrometrica to produce a plate solution and identify all of the moving objects. Astrometrica checks to see which of the objects are found within the MPC database. Those objects not found are identified as new discoveries

In order to complete the discovery, the ARI must take a follow-up image within seven days. When this is completed, the MPC officially recognizes the discovery and credits the students having conducted the analysis.

Search campaigns are run for 30 days at a time. A key goal of these campaigns is to establish ongoing astronomy research programs at high schools and colleges. These schools will be able to directly access the images from the Astronomical Research Institute on an ongoing basis, and integrate these searches into their science curriculums.

Link: International Asteroid Search Campaign

Link: Galileo Teacher Training Program on International Asteroid Search Campaign

Call for Proposals: The Planetary Society 2010 Gene Shoemaker NEO Grant

The call for proposals is out for the 2010 Gene Shoemaker NEO grants by The Planetary Society (TPS), more information from the announcement...

The trends identified in the 2006 and 2008 Shoemaker NEO Grant calls for proposals continue. Therefore, the 2010 call for proposals, issued on March 16, 2010, is identical to the ones from previous years. The deadline for applications is June 10, 2010.

Since its founding, The Planetary Society has actively supported a number of efforts to discover and characterize the population of near-Earth objects (NEOs) that both threaten our planet and hold great promise for future exploration. In 1997, the Society began the Gene Shoemaker NEO grant program to help in the global effort to meet the Spaceguard goal of discovering 90% of the 1-kilometer (0.6-mile) and larger NEOs that can impact our planet. The program honors pioneering planetary geologist Gene Shoemaker, who did so much to help us understand the process of impact cratering on the planets and the nature of the NEO population, and seeks to assist amateur observers, observers in developing countries, and under-funded professional observers in contributing to vital NEO research.

To date, the Society has awarded 32 Shoemaker NEO grants totaling more than $202,000 to observers around the world. Grant recipients have played critical roles in recovering small asteroids newly discovered by the major asteroid survey programs by providing the crucial follow-up observations to determine precise orbits for these objects.

Applications for the current round of Shoemaker NEO grants are due June 10, 2010. Grant sizes are typically $3,000 to $10,000. The Planetary Society welcomes applications from amateur and under-funded professional observers anywhere in the world. All applications will be reviewed by an international panel of NEO experts.

Link: 2010 Shoemaker NEO Grant Call for Proposals

Link: Update on Shoemaker NEO grants (18 March 2010)

Link: The Planetary Society Announcement (17 March 2010)

Help WISE Find Asteroids

How to help the Wide-field Infrared Survey Explorer (WISE) spacecraft follow-up on potential asteroids/comets it has detected. Selected Q/A from the WISE Spacecraft website...

Q: I thought WISE was going to find all these asteroids?

A: WISE will make initial observations of hundreds of NEOs and tens of thousands of Main Belt asteroids, but because it orbits the Earth over the day-night terminator and always looks up, WISE will only observe each asteroid approximately 10 times over about 30 hours.  Without more observations within about 10-14 days, all of the new NEOs and PHAs WISE finds will be lost.
Q: When an asteroid is lost, where does it go?

A: Well, it doesn't really 'go' anywhere.  Asteroids (just like planets andcomets) orbit the Sun, which makes them move when compared to the background stars.  From many observations over weeks, months, and years we can calculate a very accurate orbit for the asteroids that will allow us to find them again anytime in the future.  But if we only have a short window over which we observe the object (like the observations WISE will make) then the orbits are more uncertain, and if we wait too long we won't be able to find them again.  The asteroids are still there in space orbiting the Sun, but we don't know where.  That's why we need ground-based observers' help to nail down the orbits.
Q: So how can I help?

A: It's easy! All you need to do is look up WISE NEOs on the Minor Planet Center's NEO confirmation page (, download their predicted positions and errors, and start observing them.  In particular, you'll need to measure the position of the object on the sky, called its astrometry.  You'll also find an estimate of each object's brightness at optical wavelengths, called its visual magnitude.  This tells you whether or not the object will be bright enough to see with your telescope, and how long an exposure time you will need.

Link: WISE Mission Site (Science: Asteroids)

Presentations from NRC Planetary Science Decadal Survey: Presentations to Primitive Bodies Panel September 2009

A little older set of presentations, but some on meteor/asteroid science. Here is the information from the NRC Planetary Science website...

NRC Planetary Science Decadal Survey: Presentations to Primitive Bodies Panel September 2009. The following presentations were made to the first meeting of the Primitive Bodies panel of the National Research Council's (NRC's) Planetary Science Decadal Survey.  The meeting was held on September 9-11, 2009 in Washington, D.C.  Titles of the presentations are from the agenda for the meeting.  Adobe 8.0 or higher is needed to open most of these files.  Some are quite large and may take a few moments to load; please be patient.   If a presentation is missing from this list, it was unavailable or too large to post.
Link: NRC Planetary Science Decadal Survey: Presentations to Primitive Bodies Panel September 2009

20 March 2010

Apophis Exploration and Mitigation Platform (AEMP)

The AEMP is a Apophis mission design. They have a LEO demonstrator they are working on with King Abdulaziz City for Science and Technology (KACST). KACST is involved through a US$1M proposal to help develop the LEO demonstrator (more on AEMP website). From the AEMP website...

The Apophis Exploration and Mitigation Platform (AEMP) mission is to study the physical characteristics and accurately determine the trajectory of the NEA Apophis 99942 in order to determine the probability of an Earth impact in 2036 and mitigte the probability of that impact and future impacts by applying short term and long-term mitigation techniques.

The AEMP mission is a collaboration between four groups. The TAMU Apophis Study Group consists of graduate students developing the payload and mission concept. The undergraduate AERO 426 program, part of the Learning Through Research program at Texas A&M, is responsible for the preliminary design of a LEO flight test of the albedo change payload. NASA Ames Research Center is providing technical expertise and mission control aspects. The King Abdulaziz City for Science and Technology (KACST) will be responsible for the spacecraft bus and integration.

Link: Apophis Exploration and Mitigation Platform (AEMP) Homepage

Link: AEMP Graduate Student Shen Ge Homepage (additional documents)

United Nations Committee on the Peaceful Uses of Outer Space, Draft report of the Working Group on Near-Earth Objects (17 February 2010)

NEO report from the 47th Scientific and Technical Subcommittee of the Committee on the Peaceful Uses of Outer Space that was held from 8 to 19 February 2010 at the United Nation Office at Vienna, Vienna International Center, Vienna, Austria.

Link: Draft report of the Working Group on Near-Earth Objects (17 February 2010)

Link: 47th UNCOPUOS S&T Sub Subcommittee: Agenda and Reports/Presentations

Secure World Foundation (SWF) Report on NEOs: Legal Aspects of NEO Threat Response and Related Institutional Issues (09 February 2010)

From the SWF Press Release about a report on the findings of an international set of experts on how to deal with policy issues dealing with NEOs, following up on the work of the ASE report from last year.

In a presentation at the United Nations, Secure World Foundation (SWF) released the findings of a group of international experts that outlines needed steps and concerns in establishing a global detection and warning network to deal with possible Near Earth Object (NEO) threats to Earth.

An additional report, sponsored by SWF, has been issued by the space law department at the University of Nebraska-Lincoln, examining the legal and institutional issues linked to potential future threats posed by NEOs.

The findings presented to the UN were the result of a workshop organized earlier this year by Secure World Foundation in coordination with the Association of Space Explorers and the Regional Centre for Space Science and Technology Education in Latin America and the Caribbean (CRECTEALC). The meeting was hosted by the Mexican Ministry of Foreign Affairs in Mexico City.

An interdisciplinary group, including asteroid tracking specialists, space scientists, former astronauts, United Nations authorities, and disaster management, risk psychology and warning communication experts gathered to take part in the seminal workshop held January 18-20 in Mexico City.

Link: SWF Press Release

Link: SWF Website (Key Reports Related to NEOs)
Note: Any opinions expressed on the blog are solely those of the author. The site is not sponsored by, nor does it represent the opinions of, any organization, corporation, or other entity.