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.

27 April 2009

2009 IAA Planetary Defense Conference: Day 1 (Introduction and Session 1 Part 1/2)

Day 1: 27 April 2009 (Granada, Spain)

- Welcoming Remarks
W. Ailor, R. Tremayne-Smith

Bill Ailor: This conference is the third over the last few years: 2004 Anaheim California - 2 sponsors, (Aerospace Corp., AIAA) in 2004, Washington, D.C. (13 sponsors) in 2007, and this year 2009 (19 sponsors). White paper to be published after the conference.

Richard Tremayne-Smith: Introduces Rafael Rodrigo - President of the National Scientific Research Council (CSIC).

- Welcoming Remarks
Rafael Rodrigo - President of the National Scientific Research Council (CSIC)

Prof. Rafael Rodrigo: involved early in rockets in Spain, Spanish PI on instruments on ESA missions including ROSETTA, CSIC is a state agency, largest public research agency in Spain, research in all fields, divided into scientific and technical institutes., 14,000 people, over 4200 post-doc/PHD students, in 2008 900 M Euros (2/3 from state), produce 20% of scientific papers, represent 45% of international patents in Spain, challenges in scientific and technical point of view, discussions about asteroids and science, technical challenges discussed, mitigation is different from Deep Impact mission, mention of Gravity Tractor as mitigation concept, political point of view, international cooperation, takes astronomers out of their field and interaction with other fields.

- The IAA at 50
Jean Michel Contant (International Academy of Astronautics - IAA)
"50 Years of IAA and Asteroids and Comets"
Next year IAA will have 50th anniversary, Herman Julius Oberth and Wernher von Braun (members of IAA), went over post WWII launch options and heritage from German scientists, talked about Tsien Hsueh Shen (from JPL) who went to go found the Chinese space program, IAA founded in August 16, 1960 (von Karman) was first president, Prof. Zhuang Fenggan (Board of Trustee of IAA for 10 years, Chinese space pioneer), IAA was starting a lot of activities in 1960s, talked about various IAA members (including astronauts, NASA administrators), Buzz Aldrin's son also member of IAA, Current head is Ed Stone (from JPL), IAA runs publications/awards, MIR Station received award, Space Shuttle, (Laurel awards), in 2009 given to Sea Launch, run 12-14 conferences per year, First IAA Conference in Ukraine, last year IAA conference in Africa, etc., New IAA communication strategy, Space Dictionaries free of charge ( - multilingual, IAA introduced small satellites in 1980s, 38 studies in preparation in 2009, already published 4 of them this year (small satellite, propulsion, etc.), four recent IAA publications on space debris, specific NEO IAA study is finished - dealing with the threat from Asteroids and Comets (text is online, publication is being printed now in India), The NEO impact hazard (in terms of average fatalities per year over the time scale of occurance) versus other threat (biological, etc,), NEO as an agenda of the United Nations, Space legal issues (part of the agenda in the UN), last week first conference on legal aspects of NEOs in Lincoln, Nebraska, over 6200 asteroids discovered to date, in 2008 space shuttle impacts (1 cm diameter impact on STS - micro-meteoroid impact), Nuclear options - maybe the planetary defense community will all the redesign of nuclear missiles from military cold war to civilian protection (folks in Ukraine as interested in this in looking at redesigns), international cooperation (ground-based global network, space-based, international space watch cooperation, international catalogs) - similar to Space Debris international networks, new international space missions, psychological and sociological factors.

- Keynote
Astronaut Pedro Duque (Deimos Space)

Bio: Born in Madrid, modeling at GMV/ESA in space modeling, in 1992 joined ESA Astronaut Corps, in 1998 flew in NASA Discovery, 2003 mission to ISS, in 1995 awarded Russian Award of Friendship, director of operations of Spanish operations, Managing Director of Deimos Imaging, Spain's first astronaut

Sidetracked from main expertise and worked on flying in space, works in one of the companies of the Deimos Group (Deimos group worked on Don Quixote, also on space situational awareness), talks about ways of getting a process accomplished, process of explain-convince-prioritize-fund (also need to raise awareness, identify with principles, make it a goal), need to explain to the public, shows how he talks to the public about this, image of tsunami impacting a coastline, show that there is a lot of stuff out there, not to overemphasize the risk, on the order of other risks, what is important is that this is not detached knowledge, we have seen impacts, talks about the Eltanin impact (2.15 M years ago), shows various historic impacts, shows impact events in the last decade - craters are from the not so distant past, talks about what we can do about it, economic argument for better search programs, can we actually move it away - nuclear explosion, gentle push techniques, kinetic impact can be tested with benign test, why is public awareness important: a real goal for everyone, no need to exercise faith in the authorities of scientists, a new kind of program - should open up a new slice of the budget (for example ESA budget), is the public aware? - looked at Google Searches, over 1,100,000 pages on "asteroid danger", support ongoing efforts, support Don Quijote (being nationalist feelings in funding, technology showcase, couple of dozen kms of motorway), an asteroid hitting the earth is the worst natural catastrophe to hit mankind and something we can do something about.

- Session 1 Discovery, Tracking, Characterization
Session Chairs: Don Yeomans, Lindley Johnson, Dave Lynch

Don Yeomans:
Review of over 40 poster papers that have been submitted. Sample of interesting poster papers: "NEO Orbit Propagation Including the Yarkovsky Effect" from Astrium, "Apophis Impact Possibilities Depend Upon Astrometric Date Quality, Radar Quality, and Non-Gravitational Perturbations" by IASF-INAF (Universita di Pisa), "Detection and Tracking Capabilities and Needs for Deflection of a Small Near Earth Object Passing Through a Keyhole" (Aerospace Corporation), "Where is Apophis" (Univ. of Hawaii) - new set of optical observations of Apophis

- NASA's Near-Earth Object Program (NASA's Near Earth Object Observations Program)
Johnson, L.N. (NASA HQ, United States); Yeomans, D.K. (Jet Propulsion Laboratory, United States)

Update on ongoing updates in U.S., preface to many papers today, NEOs (any small body within 1.3 AU of the Earth, pass within 45 M km near Earth, orbits between Venus and Mars), interested in PHOs (do physically pose a risk) - within 0.05 AU, U.S. component to International Spaceguard Survey (has provided 98% of new detections of NEOs), began with NASA commitment to U.S. House Comm. of Science in May 1998. Objective: 90% of NEOs larger than 1 km, helped by NASA NEO search projects (at peak in 2005) and NEO program office at JPL, Minor Planet Center (MPC), in 2005 5 teams with 9 telescopes, in 2009 only 2 teams (less capable systems not able to find new objects), only a few nights per month of observation, >1 km sized objects - new discovery harder to make - only 2 per month now found, est. popo 940-1050 of >1km objects (850-940, 90%), 856 found as of 3/31/09, includes 83 Comets, NASA intends NEO observation program until 2012, multitudes of smaller objects (may approach 100,000 in number, only found about 5,000 objects), NASA teamed with USAF PanSTARRS - operation in later this summer, 1.8 M telescope, 1.4 giga-pixel imager, Apophis on 13 April 2029 close approach (270 m in size), 4 other potentially hazardous object (none as close as Apophis), Radar studies (20-25 NEOs/yr, from Goldstone and Arecibo), Minor Planet Center (MPC) alerts to PHO of interest, MPC possible close approach, JPL reports impact to NASA HQ (L. Johnson), JPL publishes probability of impact, planetary radar follow-up, 2008 TC3 (06 October 2008), impact the Earth in within 24 hours (2-3 meters in size based upon observational data), 0245 UTC over northern Sudan, 27 observations providing 570 observations, camera phone showed contrails, NASA funded scientists projected where in Sudan object could be found, Univ. of Khartoum led expedition (Dr. Muawia Shaddad) in March 26 issue of Nature, 10kg of material has been recovered, first time a direct line from tracked object to recovered object, ROSETTA stone of meteorite science (asteroid sample return for free), look to do this in the future, NASA Authorization Act of 2008 (plan projects to detect, track, and catalog NEOs, study has been commissioned by National Research Council, status to be provided on last day of conference).

- Long Term Impact Monitoring: Difficult but Necessary
Valsecchi, G.B.1; Milani, A.2; Chesley S.R.3; Sansaturio, M.E.4; Bernardi, F.2; Arratia, O.4; 1(IASF-Roma, Italy); 2(University of Pisa, Italy); 3(Jet Propulsion Laboratory, United States); 4(University of Valladolid, Spain)

What is currently done in impact monitoring: direct hits (collisions taking place without intervening planetary approaches, are easier to spot than resonant and non-resonant returns, probabilities are higher, example of 2002 NT7), resonant returns (are less easy to spot, probabilities are comparatively lower), deflection are less expensive in terms of delta-V, decisions are less easy to take, collision regions - keyholes) are found at particular locations of the b-plane, future impact monitoring may not give sufficient advance time for deflection, delta-t is the number of years before impact, the delta-V is approximately0.07/ (delta t) [cm/s], we have basically two problems, chaos (encounter sequences expand), dynamical model (modeling the non-gravitational effects)

101955 examined 1999 RQ36, large impact of Yarkowsky effect into future uncertainty, run a Monte Carlo simulations (500 k) samples followed until 2200, until 2060-2080 Earth encounters - MC samples are widely scattered, 2182 impact along same dynamical route, 1 in 5,000 / 1 in 10,000 impact probability, succession of expansion brings future trajectories together (do not necessarily mean that expansion of impact plane), 2162 b-plane (double keyhole for impact in 282 seen on the b-plane of the 2162 encounter), for this case - lead time is very long (should be done about 100 years prior to impact), perhaps this is atypical for 1999 RQ36

- Albedo and Size Determination of PHAs and the Case of (99942) Apophis
Delbo, M. (UNS-OCA-CNRS, France); Alberto, C. (INAF-Osservatorio Astronomico di Torino, Italy)

Size (bulk density, etc.) and inertia (helps in surface temperature) are important, Yarkovsky effect is size dependent, size D [km] = 1329 / sqrt (pv) * 10 ^(-H/5), but for NEAs this leads to serious errors due to very large albedo and H range, constrain albedo by getting spectra of asteroid, first reliable albedo and size of Apophis, 270 m +/- 60 m, polarimetry observations need to done at various phase angles, comparison with Itokawa data gives relatively good correlation, thermal infrared observations (provided you have temp. measure), measure temp. by NEATM (Near Earth Asteroid Thermal Model), derives temperature of surface of asteroids from multi-wavelength thermal IR data, accurate sizes from IR (would like multiple bands), issue of thermal IR versus Polarimetry, polarimetry can go to a higher magnitude versus IR, unless you go to space can get IR to a high magnitude, Warm Spitzer proposal - 500 hours of post cryogen time, thermal inertia information good for better models for Yarkovsky effect, observations in 2 bands is recommended, less than 100 objects with thermal models, polarimetry for 5-10 objects, not many instruments that can perform polarmetry. Astronomico di Torino, Italy).

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