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.

29 April 2009

2009 IAA Planetary Defense Conference: Day 3 (Sessions 4 and 5)

2009 IAA Planetary Defense Conference: Day 3 (Session 4)

Impacts, Catastrophism and Technological Capability to Other Areas of Endeavor
Oliver Morton (Chief News and Features Editor, Nature, London, UK)

Been to previous planetary defense conferences (in 2004), “Ways to see the world, ways to save the world: NEO awareness and mitigation in context”

Look at things in a broader context, “encounters with asteroids alter perspectives” Skhizein – Jeremy Clapin – about a man who gets hits by a meteorite – ends up standing 72cm to the right of the real world, goes to the psychologist (10 minutes long), illustrates the main them, tend to think in blockbuster terms – useful to think about a small scale – this Endeavour is also quirky and small scale – absolutely fascinating, all scientists talk about problem, you have had an extremely successful three decade success story – increased scientific understanding – the process may not have not been best sure, acceptance of K-T event, image from Nature of various experts, much to do – need more money, need a better policy framework, look at the broader shifts in people’s perceptions, elements of success: the “astronomer’s gaze” - sees farther and more than anyone else and the way they see if more divorced from touching than is any other form of vision (general way of science sees the universe) – there is second scientific realm that astronomer has privileged access to (fundamentally other) – meditated by telescopes, Hubble deep field – total perspective that disaggregates perceptive – Irish telescope (telescope) – made during the Irish famine, colleague’s book “Captured by Aliens” (book) – whole chapter of the Eagle nebula – the majesty began to fade – does the mean exist only because we insert it into the frame, what does it mean? “Comets not longer frighten the public – this is a results which science certainly has the right to congratulate itself, “astronomers should leave to astrologers the task of seeking the cause of earthly events in the star (NYTimes), overturning the astronomer’s gaze, reintroduction of the catastrophe, “100 Suns/ Full Moon” images, Lucifer’s hammer – thriller by Larry Niven and Jerry Pournelle – obvious to naturalize nuclear war – this is not limited to nuclear war – to some extent it says that civilization has already ended (fear of Charles Manson) – sense of something has gone wrong – disturbing power – brings together anxieties, Matthew Paris – the sublime – being in the presence of the dangerous – what is think about massive destruction – Indian Ocean tsunami – “relished” those numbers – auctioneer of calamity, also its humorous aspects, “Dead Like Me” – first episode – hit by falling lavatory seat from a disused Russian space station, next topic: planetary perspective: the world we experience is objectively a planet, other planet got his regularly – drove debate about earth, way of seeing mediated by spacecraft, quote from Rusty about the planetary perspective, place within a context, element of success (“long zoom” – Steve Johnson) – most periods have ways of seeing (MTV cuts, renaissance, etc.), this period have long zoom (fractals, Google Earth, social movements, difficult way of thinking) – brains did not evolve to understand the scale – Powers of Ten, the mediation is the computer – could think the computer is alienating, images from his presentation came from “Contact” when talking about the long zoom – when you pull al the way is a person’s eye – provides a continuity, once you expand your notion to include a cell phone, 2008 TC3 is the long zoom – astronomer’s gaze to truly personal, the way the world thinks about this, what we do makes it seem much more normal – scientific and cultural normalization, “you don’t have to try as hard” these days as much – “relax” – you are broadly doing what you want – a humped has been crossed, normalization into planning, sense of continuity (Hayabusa at Itokawa to Orion CEV at asteroid), twitter feed (low flying rocks) – when an asteroid passes by the earth’s orbit – thousands of people get that by mobile phone, hard to remember live in a science fictional world, normalization into research (MRO image of mid-latitude of Mars, few impact craters formed since MRO when into orbit, imager can use impacts in near real time for science, white stuff is ice), people looking at planets, the case for Mars impacts – the best use of asteroid deflection is to allow access to and sampling on substance, allow unusual access but astrobiotoically extremely relevant conditions, allow experiment with precision guidance of asteroid, prediction: there will be a deliberate impacts on Mars before there is a deflection away from Mars, Lessons for elsewhere – NEOS and their mitigation provide something like a toy model for other issues of governance, in particular there are lessons here for people trying to protect fht world from photons as well as from rocks,

Similarities between impact mitigation and geoengineering (massive potential risk, good public arguments, fringe issue, tainted with science fiction, resistance from mainstream, resistance from civil society, accidents, dramatic natural demonstration – SL9 / Mt. Pinatubo – both are examples – Spaceguard report in 1990s / NRC report) – big advantage – not part of a large serious policy debate – episodes of intense media coverage pumped by real world events, focus on small scale detection work of semi scientific type, slightly retiring risk, low level by real level political support, lobbying with specific claims, technological piggybacking, integration into normal science, changes to conceptual framework (tsunamis, keyholes, gravity tugs), the asteroid impact mitigation community has been the scene of significant arguments and disagreement, some established norms, changed its mind about things, the same time it has made process, moving between scales all seem more real, “clumsy” solutions – it is quite something to learn from the sublime – great achievement,

Session 4 Neo Impacts & Consequences
Session Chairs: David Morrison, Al Harris

Announcement of poster papers

Two posters associated with this session

- Trigo-Rodriguez (“The Impact of NEOs and their fragments recorded from the ground…”), Spanish fireball network, trakcing bright fireballs, 2002NY40 case (discovered in 2006 by network), trajectory and orbital information about daylight bodies, in 2006 obtained ninth orbit of a meteorite in the solar system Villalbto fall), Puetro Lapice (May 10 2007) – bolide object, 30cm sized meteoroid, Bejar superbolide (11-7-2008), brightest event in network, more than 1 meter in diameter entering, disruption of C/1919Q2 Metcalf comet (ended at height of 22 km altitude),

- Ferrier, et al (“Atmospheric entry of Apophis: A preliminary study”) atmospheric has a general protective effect on Apophis entry, Apophis could face heavy fragmentation (for slope around 20 degrees) leading to smaller fragment significantly slower and lighter than the initial object, ablation will deeply influence the final mass of Apophis fragments (final total mass from 0.01% to 40% of the total mass), for skimming (and rarest angles) Apophis could skip and eventually leave the atmosphere

- Alan Harris comment: many times we have been caught in general cases, sometimes many small things could do ground damage, need to address dispersion outcome of entry speeds (100m object may not get to ground, few meters across object could get to the ground)

- The Nature of Airbursts and their Contribution to the Impact Threat
Mark Boslough (Sandia National Laboratory, United States)
First part describe airbursts, in the past when we model airburst we made oversimplifications, still simplifying but making fewer simplifying assumptions, more complicated phenomena, have not done a complete quantitative analysis – greater then we thought, relative threat from LAA (Low Altitude Airbursts) is increasing, most of the integrated threat is from the large objects, 100 m / 100 Mt has 1/100 chance in century (100-100-100 event, every 10K years) – will dominate threat once 90% of object larger than 140 m, the next destructive NEO is virtually certain (greater than 99% chance), to be LAA, IPP on Climate Change defining verbally descriptive terms, less than 200 m in diameter dominated by air burst, tech development similar to threat reduction time, other reasons to deflect and fragment small asteroids (for resources and possibility for GEO engineering), put one of these in L1 point and dust (could reduce number of photons), mitigation should focus on small ones (~100 meters ) – could just be civil defense, Al Harris iconic plot – plot of the long zoom, LAAs are not explosions (unlike bombs – point source), generate upward ballistic plumes (saw in 1994 from SL9), generate downward vortex rings (smoke rings that carry a lot of energy), enhance heat transport to surface – even as KE is lost – momentum still continues - unlike bomb, carries mechanical energy downward, anisotropic radiation patterns, two types of LAA, Tunguska type – fireball descends rapidly but does not reach the ground – expands – enough surface - shockwave to surface, area to start losing energy, 1-10Mt (1908), Libyan Desert Glass (29 M years ago), fireball is much larger and descends all the way to the surface, threshold yield is about 10 Mt, its own inertia tends to expand on ground – trees would vaporize, was at 100th anniversary, no evidence of glass in Tunguska, most of the Tunguska damage is mechanical, slope angle of 35% (like Tunguska), treefall at 50 m/s, threshold is less if terrain is not flat and trees not healthy (5 mt explosions at 12 km abouve surface at 35 degrees angle), for type 2, consequences, get stationary wind at bottom at epicenter (fireball), cannot make this not happen for 15 MT explosion, Pancake model (Chyba, et al, in 1993) – revisited – vortex at surface (2-d potential effect, maybe at 3d would break up), previous Tunguska yield estimates were too high, moemetum coupling to atmosphere t, solid, earthm and tsunami amy be higher, ,Type 2 airbusrst could generate fireablls in co=nat with surface over hundred of square kilomtters fo tens of seconds (possibility ti ifind more evidence in the geological record).

K.H.: association with velocity, M.B.: 15km/s, if you had time and computational time then you could examine multiple parameter space

- Every Threatening Asteroid an Apophis
Lu, E.T. (B612 Foundation, United States)

Presented by Rusty in place of Ed, fundamental point that Ed wanted to put across – Apophis at keyhole, every deflection will involve an Apophis case, primary deflection = miss the Earth, as soon as move it away from the Earth, all along the LOV are keyhole for future impacts, total impulse for Apophis (beta = 2-10), because of uncertainty then many potential keyhole, after primary deflection, next step after primary is to determine if there is secondary deflection, shepherding = guiding between keyholes, targeting JPL/N612 GT targeting, where do you want to move it? Not going to show that there is preference but…there is an Earth in there, either you take it off to either side of the Earth – geopolitical of which direction you go in terms of movement – that issue may determine which way you go or determined by cheapest way if it is near one edge..perhaps you look at where you want to come back, the question you have to ask If you we are going to take the responsibility then where do we want to put it and why – the philosophy and criteria of targeting – begin thinking about, what you can do is run a sequence – develop a long term plan for any asteroid – not just a one time thing but what do you want to do with it – a long term plan that includes that pumps up through a series of gravitational pulses, pumping up aphelion after 80 year (5 deflections) and end up with aphelion out to hill radius , convert it to a non NEO, or use gravitational force of Mars of Venus, the concept here is primary deflection and a capability to trim (this is Rusty’s point), Ed’s point: 60-65% of cases over time have future approaches, means it is important to measure after deflection,

- The Carancas Event: a Recent Hypervelocity Impact Crater in the Altiplano
Tancredi, G.1; Ishitsuka, J.2; Schultz, P.3; Harris, S.3; Brown, P.4; ReVelle, D.51Fac. Ciencias (Montevideo); 2Instituto Geofísico del Peru (Montevideo); 3Dept. Geological Sciences, Brown University (United States); 4Dept. of Physics and Astronomy, University of Western Ontario (Canada); 5Meteorological Modeling Team, Los Alamos National Laboratory (United States)

List of distribution of attendees to PDC 2009, need more diversity perhaps, Lindley Johnson stated “that a 2-5 m meteoroid would oinly create a fireball” – this event challenges the view, close to many borders (Chile/Bolivia/Peru), the witnesses (people said that cloud of dust, and animals), photo of smoke trail, crater – diameter of 14m, almost immediately filled with underground water, Sept. 15, 2007 11:45 LT fireball was observed, explosion was observed, several pieces of material was collected, several people claimed to be sick, many seismic stations that were able to detect event, first seismic detection of an extraterrestrial impact on Earth (47 km away), estimate of orbit from data, carancas meteorites, ordinary chondrite type H4/5 (stony), hit on dry riverbed, 13.5 m crater, depth of 2.5 m, meteorite fragments in soil, quartz grains with shock metamorphism due to impact, impact velocity was >3km.s and possibly on the order of 3 – 6 km/s (based upon petrology studies and pressures on samples), size of less than one meter in size, 1-3 tons of TNT impact energy, shed that was knocked by material, 100 m away a man was turned down (but no ear drum effects), bull has one horn that is turned down because bull fell down, why is this so relevant> a fresh impact, impact crater, impact at high altitude, ordinary chondrite, seismic data, material from ground, usual picture is that a 1 ton stony meteorite producing a 14 m crater is not possible according to previous studies, initial mass was 7-12 tons, 1-6-2 m (initial velocity, 12-17 km/s, impact was 3-6km/s), seismic efficiency: 10^-3, heath problems were exaggerated, about 8 2 m meteorites per year, paper to appear in ACM issue in MAPS, rejected from nature, very few samples of the meteorite – many taken by local people,

Dearborn: said that look at the approach angle, shallow approach angle have a longer time – less ablation, angle was order of 50-60 degrees

- Near-Field Effects of Asteroid Impacts in Deep Water
Gisler, G.1; Weaver, R.2 1University of Oslo (Norway); 2Los Alamos National Laboratory (United States)

Only a few impact craters under 5km of water, all undersea craters are on the continental shelf, as asteroid has to be very big to make a crater on the seafloor, only get up to 1km diameter to get effect, tsunami deposits might be sign of deep water impacts, debate within the community about finding these (community does not fully accept this evidence), do deep water impacts make tsunamis at all, started in 2002 testing out new computer at Los Alamos, collapse of that jet that makes the tsunami wave, transient crates made usually probably asymmetrically, evolution after that is relatively symmetric, wave that is generated is surprisingly ineffective, the wave breaks in mid-ocean (high amplitude, regular tsunami has a low amplitude – propagates as shallow wave) – 1 km wave that breaks in mid-ocean – does not propagate very well, the newest simulations therefore study mostly near field effects and sediment transport, done with code called Sage (written by SAIC adopted by Los Alamos), 1000 m impact into 5km of water, 1 km sediment, basalt crust, did various trades of various diameters, resultant wave is only factor of 2 larger than transient crater, 1km (477 m at 30 km, 17 m at 2000 km), 100 m (37m at 30km, 1.3 m at 2000 km), less than 10 m for those asteroid less than 500 m, asteroid tsunamis do not resemble classical tsunamis, landslide case – extremely regular particles, asteroid impact: more chaotic interaction – more possible for energy to escape, could wish we could use another term for asteroid impact tsunamis, more of the asteroid’s kinetic energy goes into vaporizing water – then a lot less energy for tsunami, near field effects extend to tens of km away from impact site, smaller impacts are in fact comparable to sever topical storms, NOAA : a hurricane dissipates on order to 0.7 GT per day (Katrina storm surge was around 8m), 500 m dividing line, deflect asteroid greater than 500m if landing in the middle of the ocean, less smaller ones fall into the sea, if near a populated coastline, Mark and Gisler will attempt to do an airburst combined analysis, if in open sea, monitor wave and use for checking the code (“mad scientist”)

Question: depends on depth of water, shallow water issue, shallow water case interesting – the only case known that tsunami from impact is KT impact, slumps from the shaking caused tsunami, need to run shallow water cases

Question: Most of calculations are 2-D, a 3-D calculation would able to run largest computer (calc. would take a week).

- Insurance and Meteors Fall: Proposal of a Methodology for Estimating the Risk and Modeling
Consequences for the Insurance Sector in France
Garbolino, E.1; Michel, P.2; Holsapple, K.3 1Ecole des Mines de Paris (France); 2National Center for Scientific Research (France); 3University of Washington (United States)

Geographer from France, a year ago insurance company told to assess portfolio to meteor impact, meteor falls are usually considered as too improbable, need to answer the cost of damage and the vulnerability of insurance portfolio, damage assessment is a key activity, interdisciplinary approach, (technical, stakes, and cost). Territorial vulnerability (sensibility) = function (intensity, probability of occurrence, sensitivity of the stakes, intrinsic resilience, resilience to return to prior state, spatial decision support system, case study of French Rivera (Nice, 350 k inhabitants), tourist infrastructures, many ERP (establishment serving public), 4 scenarios (1m 10, 30, 50 m asteroid), airblast destroys building (small end is pushing model – clearly improvement, simple analogy taking nuclear airblast without, S 1 (6 k people, $426 M total cost) 30-50 m asteroid would destroy Nice (350 k people, $30B Euro), possible that insurance companies would be interested in covering this type of event, SDSS could be taken for emergency services,

D. ML: we do a danger talking about 6 meter objects, we create a bad false impression of risk,

C. Chapman: approach is valid approach, but the closer link between the this analysis and the actual effects of NEOs, this simple data is too simple misrepresents, get that link correct

Rusty: feel free what insurance company name – la Maif – national insurance company,
Clark Chapman: terminology, too late for NEO (should say N + E + O), meteor strikes – term,

J. Michel: demonstration of approach this

Perhaps look at equivalent events such as those that have been mentioned

- Estimating the NEO Population and Impact Risk: Past, Present and Future
Al Harris; Space Science Institute (United States)

Revised impact Kill Curve (airbursts and small land impacts, impact generated tsunami), short term warning – death plunge, probably only one out there in several km in diameter, largest size range – residual risk resides in fractional probability that one such body has not been found (not counting comets), seen that these things come in different speeds (smaller objects or larger objects going slower may delivery more energy to ground than average) – deal with dispersion of characteristics, revised kill curve published initially in 1993 – claim is that we have underestimated airburst (previous enhancements were nuclear airburst which are explosions with no momentum), Hills and Goda damage was 30 MT for Tunguska (too high), Mark suggestion as low as 3 MT (Alan Harris thinking 7.5 MT), revised kill curve, 4 times less massive body same as previous estimate, Revised kill curve for tsunami (adopted what Steve Ward/Chesley/Harris estimated run up, in report for 2002/2003 at the end of the calculation assumed that even thought only 10% of fatalities would die / the number of people affected could be used as property damage (value of Net Worth of Human, $1M/person, actual infrastructure is a factor of 10 down from cost/person), argue that tsunami damage is perhaps overdone – should based upon lives lost, elephant in the corner are the large ones (revisions make little difference for the large objects), 0.1-1km revised curve lower fatalities per year, less change to worry about in the small area, small things for surveys to find that remaining action, surveying for asteroids is like fishing (get what you get, the impact hazard in perceptive: when we get to next generation surveys (comets started getting to larger portion of threat), we have discovered half the objects the size of Apophis (next generation survey will generate Apophis – but not as many as feared), not going to be worried about Apophis, the survey is 84% complete to 1km, 95% complete to 2km, only a small fraction of Tunguska size NEAs have been found, next generation durvey should find 25% of objects that pose ground impact, short term warning – TC3 event – 20% chance to look at right part of sky, 10% chance of catching Tc3 event with current survey (found one after decade of survey is not surprising), in principle LSST may see things on a monthly basis (but no follow-up), worried about impact hazard – the next generation survey will find anything that make to the ground – LSST will pick things pick more than one month in advance (the nest you can do is 35% since you are not watching the other part)

Global impact events: 1 km was selected as lower limit where you could believe you have global effects, 1 km object = largest volcanic event (similar)

D. M: goal is 90% of 140, but that includes more as well

- Casualty and Fatality Rates of Massive Extinction After Asteroid Impact with Earth
Ortega, G.1; Bavandi, A.1; Weikert, S.2; Giron Sierra, J.M.3; Laurel, C.4 1ESA (Netherlands); 2ASTOS Solutions GmbH (Germany); 3University of Madrid (Spain); 4Periapsis Visual Software (United States)

Job is compute optimal trajectories at ESA, earth catastrophic event more than 10,000 people killed at same time, Maximum Probable Loss (MPL): greatest financial amount of loss from previously defined event, used ATOS tool (included DARS – debris analysis re-rentry spacecraft), also included DIA (debris impact analysis) and RAM (risk analysis) , parametric analysis of various asteroid sizes, formula for impact, various simulations of various cities, risk of impact is larges than 1 in a million risk of death use in ESA terms

Panel Sessions:

M. Boslough: One of the ways that Tunguska was overestimated, momentum would carry fireball all the way to the surface if using older numbers, look at the intensity of the shock wave from a nuclear explosion you get more danage then you see at Tunguska, concluded that it may be a smaller energy (3-5 MT may be 1 in 1000 year event) but also less frequency (larger events where getting to be implausible)

A. Harris: 300-500 year event for Tunguska, the population has dropped by a factor of 2-3 and energy has also dropped

A Harris (the younger): One phenomena about electromagnetic pulse and whether we would expect that and waht sort of size?

M. Boslough: observationally there was an E-mag pulse effects for Tunguska and SL9 impacts , you will get a plume (1000 km high for Tunguska) - different process for EM pulse, small scale events have caused transmission lines to fail, ionization effects can be part of the hazard - something that we would not want to ignore

Dearborn: scaling nuclear by yield for EMP, can see EMP in conventional explosives, have looked at EMP increase for conventional explosive, trying to get someone in his lab to look at it (for other reasons)

K.H.: want to focus on Hill and Goga approach...most of the energy goes into ground, Hills and Goga may overestimate using nuclear blast data for ground effects

A. Harris: Jack Hills fan of tsunamis - made the assumption that even a 100 m object (crate damage), curves at top may be not correct,

D. Morrison: blast wave for large object may not be that important

J. Michel: point out that everyone is making models, rate of numbers for phenomena, resolution for modeling is higher than what can be done, what are the things that are uncertain

A. Harris: Mark B. did a poster at AGU (from disaster movies), had in the last few year (asteroids actually hitting something, Peru and Sudan) - we do not see disaster movies, forget the world is very empty place, highly unlikely

M. Boslough: started with disclaimer - qualitative outputs are what are important, done the next level of analysis, point source - now point source with momentum, does not include viscosity / only 2-D, a good fluid dynamics simulation, how to calibrate: airbursts happen more often

Oliver: catastrophic interpretation of cities, chances of hitting cities are small, ways to have maps for blast area of Tunguska (compared to cities), guard against,

A. Harris: Chance of Tunguska hitting your town about the same as you drowning in toilet

R. S.: Political decision makers will mis-perceive and worst case will be the perception of impact

Gisler: calibrate codes with smaller events and tsunamis in the past, "perhaps of computing is insight and numbers" look at smaller events, Van Doren effect – based on results of underwater nuclear tests, these waves are similar to impact tsunami waves, small asteroid impacts in water (are dangerous on a local basis), if something were to provide 2004 tsunami event (that is still far short of global catastrophe),

A Harris: looked at various different historical report, the integral of all reports multiplied by credibility is greater than one, cars/mailboxes, by all odds someone should have been killed in the last century

Audience member: Source says 190 from (John Lewis book) last century killed

Tancredi: Terrestrial material on the side indicated that impact parameters

2009 IAA Planetary Defense Conference: Day 3 (Session 5)

Session 5 Policy, Preparedness, Deciding to Act
Session Chairs: Andres Galvez, A.C. Charania

- Report on University of Nebraska-Lincoln Conference "Near-Earth Objects: Risks, Responses and Opportunities–Legal Aspects"
Frans von der Dunk (University of Nebraska-Lincoln, United States)

"ASE NEO Committee report: Asteroid Threats: A Call for Global Response," report came to three conclusions: there is a capacity to detect / a capacity to act / missing of international decision making structure, risks not distributed in propositional to capabilities (Sudan and Peru not space fairing nations), risks not proportional to costs, who is going to pay, these are places where the law comes in, report delivered in Sept. 2008 briefing of key UN players and major states, Action Team 14 within the UN structure, what is the role of the legal subcommittee of COPUOS?, have three groups and UN Sec. council has three “groups” underneath (specific groups of functions), US Sec. Council to mandate whatever happens in a specific concept of deflection, UNL conference: setting the scene / legal/political aspects / international legal aspects and exploring NEOs and domestic US laws of NEO, and intergovernmental panel on Legal and Policy Aspects of NEO response activities (every continent representative), role of the military in various scenarios, liability (for not reporting, for not deflecting, for not being successfully, past incident with NOAA lawsuit about Indian Ocean tsunami information being withheld), what is asteroid is coming to N. Korea and US does nothing about it, liability convention (current legal regime), should we establish cross-waiver (like the ISS IGA- but that is between parties), good Samaritan, second major legal issue is international humanitarian responsibilities (obligation of provision of relevant information) - perhaps an institutional framework (builds trust) – parameters for action before actual case arises, obligation of protection of fundamental human rights, property issues (with a view to private involvement, current legal regime is unclear, ownership of minerals versus entire body, pressing need to make sure international and legal aspects do not get lost, need to further analyze legal issues, website:

M. Boslough: telescope on asteroid – does it matter if you land the asteroid about who owns it?

von der Dunk: How about owning the mineralogical rights: IP: that exists in outer space, the problem arrive in moment when you extend the ownership to the mineral, one exception with risk to mankind – if you get information on might hit the risk to Earth you should share, composition for commercial purposes should be protected

- NEO Mitigation and Coordination with the Disaster Management Community
Chapman, C.; Schweickart, R. (B612 Foundation, United States)

Doubt if something were to happen there would be a broad based knowledge within the U.S. or globally would know how they would respond, need to respond between astronomers and others is more urgent, address the power law (small ones happen much more often that big events) – crucial thing for a practical perspective – smallest predictive impacts that might be dangerous (Skylab – re-entry was worldwide news), past PDCs have examined far larger NEOs than most likely, for every Apophis more than 50 Tunguskas, what is the smallest NEO that is dangerous – vital issue (if it is too small they will not care, metallic objects are dangerous but rare), SDT report in 2003 thought 50 m, Boslough suggest 30-40m, should we be unconcerned about 25 m object, Al Harris chart is not diameter but have an H value (uncertainty a nominal 25 m body may be 50 m in diameter), short term warning – the new reality, better than 1 chance in 3 that the Spaceguard will provide short term warning (few weeks) during the current decade, TC3 teaches us that we have an early warning system – rethink communication channels, 2008 TC3 : 4 m asteroid (an annual impact on Earth) – astronomers have overlooked short term Spaceguard survey, current survey will find 35% of NEAs > 30m on final plunge, will find more on final plunge than one long in advance, public officials must make decisions much more often than NEOs will actually hit, case of marginal impact scenarios, virtual impactor search (JPL impact page shows low probability impacts – cannot be observed before final plunge) – search for these virtual impactors weeks prior to impact – if coming from the Sun, radar would be required, we have risk corridors, some semi-serious is impact predictions that require analysis leading to no action, short term impact warning, mentioned short term warning , look at ASE recommendations

- Near-Earth Objects within the European Space Situational Awareness Programme
Koschny, D.1; Bobrinsky, N.2; del Monte, L.3
1ESA/ESTEC (Netherlands); 2ESA/ESOC (Germany); 3ESA/HQ (France)

Objective of SSA programme declaring: environment, threats, and the sustainable exploitation of outer space (three segments: space debris, space weather, NEOs, later: imaging), most of the effort is in space debris, in Nov. 2008 – preparatory phase started, last for 10 years after this phase, what does it consist of: network of sensors (ground and space-based), data centers, common data policy, optical programme, not a science driven needs, science needed to do program, do not have to justify by scientific nature, shall issue impact warnings, customers and users (replace decision makers with government, insurance companies want to make sure it is low risk, a customer as one who pays), NEO Data centre (not one place – distributed amongst many countries in ESA), status: write a customer requirements document – will be written in the next few weeks, start creating a European network of sensors (Intelsat will pay for orbital debris information), set up prototype service until 2009, just finished ESA external document,

- Results of Multi-Agency Deflection and Disaster Exercise
Garretson, P.1; Johnson, L.2
1Council on Foreign Relations (United States); 2NASA/HQ (United States)

New report is a summary of events, a simulation was performed of a short term days) and long term (years) impact scenario with members fro various US government military and civilian agencies, a new report is out that outlines results, it is not an official position of the USG or any of the agencies involved, it would help into insight into real decision making, has done previous work with the USAF Future Concepts office (including backcasting analysis), why event held? Look at high catastrophe events with high consequence, a letter from NASA HQ was secured to help obtain momentum for event, most people in simulation, “if not us, who? Would do such a simulation game, initially participants may have thought this would have a sci-fi nature to the event, 27 people plus 3 offsite participated in the event, multiple agencies- maybe OSTP in the future, most agency role players felt the responsibility for planetary defense against PHO was someone else’s responsibility, attendees were mostly action officers from their various organizations, looking for the richest (but perhaps not most probable scenario), called 2008 Innoculatus, Lindley J./Mark B./Mark ) in room, went for the broadest swath of people, two groups looking at different threats (same people, consecutive scenarios), first threat was 72 hours from impact (lost 10 hours getting ready in simulation), 50 m metallic body headed for D.C. area, 270 m rubble pile hitting the Nigerian Coast, missing some key people (namely state and local planner), one of the issues is that the error ellipse for impact is so broad – emergency response it is difficult to optimize, scenarios basically made 2029 today, future planning scenarios may be less ambitious, insights: NEO plans not captured in existing plans, NASA does have some sort of a contingency process – other agencies do not, need for more senior players potentially (not too senior), most people did not laugh or giggle – there was a feeling that “I need to need to tell the boss about this,” very complex – overlapping nature of problem, need for documentation, no consensus achieved on responsibility – argued it was “the other guy” – some consensus that ground response was DHS perhaps, some felt the response would be similar to a Manhattan project with all resources ay disposal, software tools deficit to support decision make and communicate information, need for a federated systems – end estate would be a turn-key model that accepts the best data, turnkey mission planning and modeling, significant effects not captured, public may be aware before senior decision makers, limited time for evacuation decision before best information will be available, architecture for short warning time, public safety requires federal government, preferred approach for short notice scenario was stand-off nuclear (for the 7 year scenario felt there was a need for maturation, not for future scenario planners – some players though tools/simulations were distracting, next time include all agencies, media/press could be useful, NSC added, use higher level representations

- The Need to Match Action with Legislation: Some Inconsistencies in the OST
Azcarraga Arana, A.1; Gonzalez Ferreiro, E.2
1Sener Ingeniería Y Sistemas (Spain); 2Cede (Centro Español De Derecho Espacial) (Spain)

How to bring together experts in all areas (science/engineering + policy): financial crisis + climatic change, if you are able to detect something in diameter, everything has been in the military – nothing is wrong with that, example of Russian anti-submarine cruiser for Black sea (since aircraft carriers are forbidden), solve problem and not give artificial names, need for global international coordination, Galileo example is not a good example, new international body – as soon as one member asks for action – take action, look at the OST and start changing it immediately, afraid next COPUOS meeting not a clear sense of urgency there, need more media papers, change the word NEO, use PHO, don’t let things go to manana,

Panel Discussion:

28 April 2009

2009 IAA Planetary Defense Conference: Day 2 (Sessions 2 and 3)

2009 IAA Planetary Defense Conference: Day 2 (Session 2)

Session 2 Mission and Campaign Design
Session Chairs: Mariella Graziano, Ian Carnelli, Andreas Rathke

- R. Tremayne-Smith
Discussion of orbital debris problem, vide of U.S. recent AST-like event / Iridium impact, conception of LEO not the same as before, not about mitigation, checking for debris done casually, in low earth orbits need to have propulsion/maneuver, A-Train set of satellites has to move through this region, even more disciplines, getting more difficult to get space open for business, going to need same mechanisms for the orbit area,

Announcement of poster papers
- MAAT: NASA Ames research study, ESPA ring variant of NASA ARC Common bus, secondary payload, 10 month long launch opportunity, 3.1 km/s Delta-V (includes margin), ability to vary launch site, 2014 science mission for 6 months, modified LCROSS instrument suite
- Optimal control of gravity tractor spacecraft near arbitrarily shaped asteroids (M. Gehler, et al), see the influence of arbitrary gravity field on control forces, how GT could be optimally controlled, Discrete Mechanics and Optimal Control applicable to hovering control for very close to asteroids, solar sail size should be matched to asteroids, used 1 asteroid radius (about 500 meters),
- PANIC – mission concept study for mini autonomous lander (NASA Ames summer study), a micro scale lander (three instruments), total mass (9kg for 48 hours, $25M)
- Evolutionary optimization in a conceptual design of a NEA mission, what is netter of a single impacts or multiple kinetic impactor
- Small Solar System Body mitigation (J.T. Grundman), a realist approach, when down the list, and looked at all the problems

- Didymos Explorer and PANIC: Asteroid Concept Studies of the S4P Program at NASA Ames
Rozitis, B.1; Bellerose, J.2; Cook, A.3; Fahnestock, E.4; Mester, C.5; Murdoch, N.6; Olds, P.7; Reddy, V.8; Schindler, K.9; Thomas, C.10; Yamaguchi, T.11; Asphaug, E.12 ; Marchis, F.13 1The Open University (United Kingdom); 2JAXA/JSPEC (Japan); 3Rensselaer Polytechnic Institute (United States); 4University of Michigan (United States); 5Stanford University (United States); 6ESTEC/ESA (Netherlands); 7UARC/NASA Ames (United States); 8University of North Dakota (United States); 9University of Dresden (Germany); 10Massachusetts Institute of Technology (United States); 11The Graduate University for Advanced Studies (Japan); 12University of California (United States); 13SETI (United States)

Develop 1-2 concept studies for small spacecraft, integrate small spacecraft exploration, train the next generation of scientists/project leaders, 11 students from various backgrounds, no NEA binary and no M type asteroid has been visited yet, decided on Didymos (1996 GT), a Mars crossing Amor binary, also a PHO, low delta V, 750 m diameter (primary), accomplish the first in-situ investigation of binary asteroid, science objectives: asteroid geology, shapes and gravity fields, Yarkovsky effect, Yorp effect (if enough force then potential to make a secondary object), asteroid composition (link asteroid and meteorite classes), six instruments, use of Delta II vehicle (launch on 12 Nov. 2014), mission duration of 2 years, flybys at 5km and 3km, perform close approach, minimize eclipse time so hovering becomes a better approach and allow for secure deployment for lander, 151.8 kg (dry) /. 307.9 kg, cost ($136.5 M with 30% contingency), 207.6 W, Didymos explorer mission will allow thorough study, Q/A

- Foresight: Designing a Radio Transponder Mission to Near Earth Asteroid Apophis
Charania, A.1; Olds, J.1; Koenig, J.2 1 SaceWorks Engineering, Inc. (SEI) (United States); 2SpaceDev, Inc. (United States)

- The Challenge of Navigating Toward and Around a Small, Irregular NEO
Gil-Fernandez, J.; Prieto-Llanos, T.; Cadenas, R.; Corral, C.; Graziano, M. (GMV, Spain)

Examined multiple types of missions, impact missions and rendezvous missions, proximity operations, need high accuracy for navigation (around one meter), new sensors, requirements for NEO missions are highly demanding for GNC, robust GNC system, result shows impactor only could potentially do mission without specific shape model (not relying on shape information)

- PROBA-IP: An ESA Technology Demonstration Mission Targeted to Apophis
Cano, J.L.1; Peñín, L.F.1; Cornara, S.1; Santandrea, S.2; Marcos, F.3; López, A.3; Jentsch, C.4; Bernhardsdotter, E.5; Taylor, M.6; Page, O.7; 1DEIMOS Space S.L. (Spain); 2ESA / ESTEC (Netherlands); 3EADS CASA Espacio (Spain); 4EADS Astrium Satellites (Germany); 5SSC (Sweden); 6SSTL (United Kingdom); 7SciSys (United

Follow-on to Don Quixote orbiter (Sancho), consortium performing for ESA, related to in-orbit demonstration of autonomous technologies, PROBA-2 (Sept. 2009 launch): solar observatory, PROBA for formation flying, PROBA-IP take technologies to interplanetary field, need to determine a cost specific mission, scientific goals only if margins will allow for it, current study is a preliminary concept evaluation, launch before 2015,choose asteroids close to the Earth, count on cheap launchers, use of low thrust propulsion, reuse an upper stage design (use of LISA Pathfinder’s propulsive stage being developed for ESA already), initial filter sin asteroids resulted in 60 asteroid (Apophis was promising and choose as primary) – choose 1989 UQ selected as a back-up launch in 2017, VEGA launcher, need for active control during to high unstable dynamic orbit, analysis of a Phto-Gravitationally Stable Orbit, consideration of different types of SEP engines, arriving with low velocity, departing in Jan 2015, 1.892 km/s departure velocity, arrival date in in 2017, 435 kg wet mass / 350 kg dry mass, delta-V of 3.9 km/s, GNC technologies (autonomous GN&C in cruise/approach/operations, use of DTU’s advanced stellar compass used as DTR/NAVCAM/WAC), power (two wing arrays, HEMP 3050 engine, easy to control – control mass flow rate – good for autonomous control), ACS (three axis stabilize, X-band, in middle of the study, study ends in summer, provide ESA with design concept at that point, potential for accurate determination of Apophis orbit and features, orbiter acting as beacon for deflection techniques

- Exploration of Near-Earth Objects via the Orion Crew Exploration Vehicle: A Planetary Defence Rationale
Abell, P.A.1; Korsmeyer, D.J.2; Landis, R.R.3; Jones, T.D.4; Adamo, D.5; Morrison, D.6; Lemke, L.6; Gonzales, A.6; Gershman, B.7; Sweetser, T.7; Johnson, L.8 1NASA Johnson Space Center / Planetary Science Institute (United States); 2Intelligent Systems Division, NASA Ames Research Center (United States); 3Mission Operations Directorate, NASA Johnson Space Center (United States); 4Association of Space Explorers (United States); 5Trajectory Consultant (United States); 6NASA Ames Research Center (United States); 7Jet Propulsion Laboratory (United States); 8NASA Headquarters (United States)

Paul Abell, feasibility study within Constellation program office at JSC, led out of Ames Research Center, Rob Landis/Ed Lu, a few folks at JPL (for trajectory analysis), Tom Jones, Bret Drake – sponser, this is only a Phase I feasibility study, NASA has not endorsed this yet, work done to date based on 4.5 month effort, a phase 2 study is as yet to be determined, proposed since 1966 (Eugene Smith) – “A Manned Flyby Mission to Eros”, no changes to Constellation element performance, established 4 misison concepts (2 bookends) based upon planned Cx launch system, at mid term considered mid-volume concepts (Ares V concepts), determine mission length options, Lower bookend (EELV for Centaur upper stage) + Ares I, Upper bookend (ARES V for EDS + LSAM) + Ares I, mid-volumes (use Ares V concept for Orion launch), for mid-volume (EDS and Orion SM perform rendezvous for 7-14 day visit with 20-75 outbound segment, which NEOs are a good target of opportunity with Earth-like orbits with low eccentricity and inclination, used JPL HORIZONS database, analyzed 90-120-150-180 day options, 9 NEOS founds within 2020-2035, 1999 AO10 is one potential target (2025/2206 mission) – 11.2 km/s reentry speed, value of human exploration to NEOs (exploration, science, and general public), expand human capability beyond low Earth orbit, asses resource potential for NEOs, gain operational experience for complex tasks (human/robots), assess psychology of crew autonomy at 10-20 second round trip for deep space, help indentify most efficient deep space exploration architectures, sample return, perform unprecedented deep-space voyage experience, would be a stepping stone type mission, demonstrate the way to Mars, understanding NEOs helpful for future impact threat, Can ye do this (Yes we can do it, Constellation program elements can support crew of 2-3), need to leverage next generation survey to find more targets, in depth Phase 2 mission analysis (applicable innovative technologies, radiation shielding, etc,), question: need to balance cost and missions (we have not done any cost estimate, not going to be a science mission/exploration mission/) – many communities, high cost – similar in cost to a lunar sortie (not the same as space station) – not the same as lunar outpost, question – chances to continue the study and do the mission- a lot of interest at NASA HQ, liked to do Phase 2 – interest at HQ leads to believe that Phase 2 will happen, holding pattern because of not permanent administrator

- Navigation and Guidance of Hayabusa around the Tiny Asteroid Itokawa
Yoshikawa, M.1; Kawaguchi, J.1; Hashimoto, T.1; Kubota, T.1; Terui, F.1; Ogawa, N.1; Ikeda, H.1; Kominato, T.2; Matsuoka, M.2; Uo, M.3 1JAXA (Japan); 2NEC Aerospace System (Japan); 3NEC Toshiba Space System (Japan)

Hayabusa changed the concept of small NEOs, before we thought many craters on Itokawa – surface covered with boulders, the study for Hayabusa is also important for spaceguard,June 2010 Earth reentry, have a brief history, first gravity swingby with low thrust propulsion, ground based operation was limited during Hayabausa touchdown (delay of 32 minutes and low bit rate of 8 kbps), intelligent GN&C is required, discussion of touchdown marker, during first touchdown maneuver - an obstacle was encountered and then went into feeefall near asteroid (unexpected), believe during the first touchdown may have captured some pieces of asteroid, mass estimation based upon using R&RR and LIDAR data, bulk density of 1.0 g/cm^3, Itokawa may be a rubble pile object, movie : "Hayabusa - Back to Earth" , next mission would like to know information inside the small bodies

- A Dawn-based Gravity Tractor and Kinetic Impactor Mission Concept Study
Wie, B. (Iowa State University, United States); Lam, Q. (Orbital Sciences Corporation, United States)

Changed name: NEO Deflection Systems Design, Dawn-based gravity tractor, multiple gravity tractor option also examined, NEO Deflection alternatives, three options (nuclear standoff or surface, kinetic impactor, gravity tractor, basic system (TII + Upper stage + 1400 kg payload – Dawn 900 kg GT or 1400 kg kinetic impactor or 900 kg interceptor with 500 kg nuclear explosive device), option 1 (Delta IV Heavy + Upper stage of Star + 6000 kg – multiple GT) , Option 2 (Ares V + Upper stage + 55 MT payload), Dawn spacecraft not designed for GT mission, use existing S/C bus technology, Dawn system to be presented at IAC 2009, two launch windows for Dawn based GT (2020 and 2021) for Apophis, delta-V from GTO is 3.45 km/s, Delta-IV heavy concept (three GTs/impactors/interceptors), GT mass = 2823 kg (wet mass, 1233 dry mass) for each GT, reason for multiple gravity tractor due to single point failure – more GTs allow for larger delta-V and more robust and reliable, do not need active station-keeping with multiple GTs – need more launch vehicles for such a system, paper in Journal of Guidance/Nav. Control, examined advanced low thrust propulsion, also a crewed 180 day NEO mission to Apophis – departure 10 September 2028, 160 days to Apophis – thought Ares I and Ares V is not enough (having trouble using design) – one page summary of ongoing project to be done during the summer, another poster paper on examining nuclear standoff for NEO deflection – estimation of optimal standoff of about 200 m (not 20 m as usual value) for a 1 km “solid” NEO, if GN&C control system has to meet 20 m optional standoff distance (this is too difficult for GN&C system) – we have to make decision (standoff explosion during fast flyby or rendezvous), position accuracy than 50cm (3 sigma), collaborative research with GMV aerospace for NEO terminal guidance, need large scaled funded R&D program for developing, testing, and deploying)

2009 IAA Planetary Defense Conference: Day 2 (Session 3)
Session 3 Deflection Technologies & Simulations
Session Chairs: Dario Izzo, Patrick Michel

Selected Posters:
Gary Johnson (Texas State Technical College), “An Electrostatic Variation of the Gravity Tractor “, Add an equipment kit to charge up the asteroid ans use the force of the electrostatic attraction (electrostatics as upgrade), “it smells good”, encourages community to take idea and run with it
Sanchez, J.P (Univ. og Glasgow): Consequences of fragmentation due to a NEO mitigation strategy
Pete Swan (from the space elevator community), NEO community, space elevator will be here for launch in 20-30 years, where do you park a space elevators, elevated parking structure for planetary defense pre-positioned assets
Adriano Campo Bagatin , “Response to collisions by NEA with gravitational aggregate internal structures”, study of collision outcomes depends on target’s number of components, the detailed internal structure of the impact region seems at least as important as the overall internal structure (texture) of the target

Antoni Perz-Poch, “Multi-spacecraft Electrostatic Tractor with Swarm Optimization”, real time coordination among satellites with an 4-6 satellites each 10 kV
Andrew Bacon, A Method for Fragmentation for Apophis, low cost fragmentation by using two or more Fregat Soyuz as smart impactors at resonant seismic frequency of Apophis to create an even distribution

- Methods for the Deflection of Threatening Asteroids: Some Problems, Theoretical
Considerations and a Few Myths
Keith Holsapple (University of Washington, U.S.)

Overview of some of the proposed methods for deflection, what do we need to do? After the astronomers say what we do, deflect (around 1-3 cm/s 10 years prior), disrupt or disperse it, or destroy it, a myth (destroy it): to vaporize a small 100 m asteroid requires about 30 Mtons of energy, you only change state, myth (“deflection is not possible in space”), danger of breaking it up is overestimated, delta momentum for deltaV for 1cm/s is 10^7 for H (momentum), table of mass for 100 m object: solid rocket (130 tons), gasoline (90 tons), dry cow dung (80 tons), bipropellant liquid rocket (70 tons), 10 km/s impactor (30 tons), 50 km/s impactor (6 tons), Fusion nuclear bomb (0.1 tons), E/C = c^2 ( 0.7 kg), things less than 30 tons could be considered, disrupt and dispersing it: needs 10^2 J/kg of asteroid, at or just under the surface, nuclear bomb (buried, surface, standoff), impacts unlikely to do except for smallest bodies), another myth: destruction energy might worsen the situation, there are neverl several large pieces in an impact disruption, typical fragment disruption velocities are several m/s, escape velocities are cm/s, tnes of cm/s are enough to miss the earth on the scale of a year, disruption would not be a problem if a year out or more, blowing it up at the last minute may work, how (bombs, bullets, gravity tractor), not good ideas (attached, surface landing, Yarkovsky, e-mag forces, tether), ones to focus on (nuclear, solar, laser), nukes are the last resort, is a method works better simply crashing its mass into the asteroid compared to its design method, forget it..unless there is a compelling reason, gravity tractor (10-100 factor just to impact), GT requires large mass/long time, no good ideas with interaction with surface for laser ablation (need to know dynamics), nice picture (MADMEN) – real surface tie it down, some methods have political problems (nukes in space, moving something slowly over the course of the earth –liability/weapon), composition problems (impacts, nukes, mass drivers, lasers, solar), porous materials are very good at absorbing energy shock, the forces on any stake in a rubble pile scale linearly with gravity (10^-5 to 10^-6 probability) – fastening with biggest item may not work, controllability/precision, robust mission with multiple instantaneous times, further analysis of nuclear (for porous material need to move into 20 m close), bullets (beta factor – due to blow back, do not know how much), B=1 (perfectly plastic impactor), other value it becomes a cratering problem, porous materials very little of beta (experiments would be good), with a single impact (200 m), multiple impact could do a km, an approach along the trajectory is not required, can hit it off center, no going to disrupt it, traj accuracy (mass, shape, spin, thermal inertia), kinetic impactor (just need mass) – thus Don Quixote would be preferred mission.

- Asteroid Deflection by Means of Electromagnetic Forces During an Earth Fly-by
Sanjurjo-Rivo, M.; Peláez, J. (Universidad Politécnica de Madrid, Spain)
Few works devoted to the analysis of deflection maneuver during Earth flyby (magnetic field and enhancement of gravitational interactions), uses a patched conic approximation (objective: avoid keyhole), electrostatic interaction (charge asteroid, electrodynamic tether (rigid attached to the asteroid)l – not feasible, can use these forces in indirect way, e-d tether modify the shape, electrodynamic tether, tether length of 350m E-d effect will be greater than the gravitational one, developed some techniques for electrostatic and E-D tethers

- Simulations of the Deflection of an Apophis-like Object
Jutzi, M.1; Michel, P.2; Benz, W.1 1University of Bern (Switzerland); 2University of Nice-Sophia Antipolis, Côte d'Azur Observatory (France)

Assumptions: (Apophis like object) – impact energy will not cause, why is is difficult to model

- Dynamical Characterization, Control, and Performance Analysis of Gravity Tractor Operation at Binary Asteroids
Eugene Fahnestock (University of Michigan / NASA Jet Propulsion Laboratory, United States)

Extensive study done at the request of B612 for using the GT to deflect hypothetical impactor (2016 NM4) by group at JPL, no detailed study of using GT at the binary object, apply prior GT control to case of binary, what is the differential performance penalty for binary versus solitary, 2016 MN4 – shape models from 1999 KW4, small size binary in analysis (65-24 m), placement of GT such that avoid collision and to maximize towing effectiveness, assuming SEP system, cant main GT thrusters by some angle to avoid exhaust impingent, computed ideal values (static setup to maintain equilibrium, GT station-keeping approaches, can get better control using simpler control algorithm, teo regions with good performance metrics (interior region meaning inside secondary ~ 215m, exterior region d ~ 430 m), conclusions: delta-V accumulations more likely to be near the top of their spread, mass loss more likely to be near the bottom of its spread, in relative terms there is a performance penalty compared to GT operation at solitary NEO, penalty for being exterior, completing deflection operation a binary NEO still quite achievable in absolute terms (even with simple control approach). 1999 KW4 may be typical (average period around 24 hours, KW4 is less than, KW4 is much smaller than those one would study)

- The SHADOW Mission: Deflecting APOPHIS with a Flotilla of Solar Shields
Prado, J.-Y.1; Perret, A.2; Boisard, O.2; Bertrand, R.1 1CNES (France); 2U3P (France)

Increasing number of resonant orbit with time, about 1 in 50 chance for an impact with the earth between 2036 and 2130, attempt to define safe areas for one century, SHADOW is tow parts, one is observation, another is deflection mission, Part 1: observe and track for Yarkovsky effect, Part 2: Apophis deflection by canceling Yarkovsky effect – developed in parallel with flotilla of solar shields, high Delta-V needed – useful for solar electric propulsion, Yarkovsky thesis in late 1800s, 1987 : small variation in LAGEOS, 2003 first observed in GOLEVKA, YE is tiny (10^-10) – effect like a butterfly on an aircraft carrier, main effect on semi-major axis, shadow 2 mission: transfer module using SEP carries 4x200 kg solar shields, shields controlled by transfer module, sail hovers a few km over the asteroid, no direct link of individual sails to Earth, chemical propulsion needed for balancing photonic pressure, only effective is there is substantial YE, next approach 2012/2013 must not be missed, excellent opportunity for worldwide training, solar shield/sail technology not proven, in mythology: Sun always tried to destroy Apophis, question: disagree with keyhole analysis

- Asteroid Deflection Theory: Deflection Charts and some New Deflection Options
Izzo, D.; Chy, C.H.Y. (European Space Agency, Netherlands)

New title: Asteroid Deflection Theory (Orbital Mechanics), Delta-V models are a.) full n-body propagation and b. keplerian propagation, if libration cycle tied to resonance begins, analytical methods lose accuracy, closed form solution is a formation flying problem between nominal asteroid (mother) and its deflected image (daughter), for small DVs the linearized rendezvous equations hold, delta-V use in-plane, optimal direction is along the velocity vector, optimal angle is between 0 and 1 degree for most of orbit, issue with model - linearization/integration error grows with time / accounts for only instantaneous velocity change, disregards the asteroid-Earth phasing and does not account for system design, the deflection formula (equation for acceleration and miss geometry), deflection charts: push time and start time relationships – show trade-offs given a particular encounter, but these charts do not tell us the optimal deflections, crucial to understand the strategy for system design and requirement for amount of deflection, larger deflection distance may mean kinetic impactor may be superseded by other options.

- Ariadna Encounter 2029: Introduction to the three studies
Call from ESA for ideas and concepts.

- Catastrophic Impact Energy Threshold for Disruption of Small Porous and Non-Porous
Asteroids: a Crucial Information for Deflection Strategies
Michel, P.1; Jutzi, M.2; Benz, W.2; Richardson, D.C.3 1University of Nice-Sophia Antipolis, Côte d'Azur Observatory (France); 2University of Bern (Switzerland); 3University of Maryland (United States)

Previous: NEOMAP at ESA (2004), how can we be sure that we will not destroy the body? The larger the rocks the weaker they are, at larger radius energy goes up, simulating a catastrophic disruption? Computing the fragmentation code, various types of internal structure, non-porous versus porous body fragmentation, reaccumulate to form family members, not so easy to destroy a body, first complete simulations of asteroid disruption (Science in 2001 and 2003), objects greater than 100m are rubble piles, disruption by impact of a 25 km asteroid (shape comes out similar to Itokawa), two regimes (strength and gravity) for disruption energy versus radius, for gravity regime no difference between porous or non-porous, for strength regime, porous a little more energy than on-porous, disruptive regime: largest output is 50% of target body, generate a lot of aggregate, characterized catastrophic disruption for targets of different sizes, etc., Marco Polo mission in assessment study for ESA Cosmic Vision 2015-2025 at ESA, proposed ESA-JAXA partnership, have not investigated macro-porosity of rubble piles in this same fashion, question: did we ever have an integrated small bodies (did we ever have monolithic bodies)

- Designs of Multi-Spacecraft Swarms for the Deflection of Apophis by Solar Sublimation
Vasile, M.1; Maddock, C.1; McInnes, C.2; Radice, G.1; Summerer, L.3 1University of Glasgow (United Kingdom); 2Strahclyde University (United Kingdom); 3ESA Advanced Concepts Team (Netherlands)

Years ago did a comparison of multiple deflection criteria (miss distance, warning time, spacecraft mass in orbit), found surface ablation was not as bad, nuclear blast led to in some cases unwanted fragmentation, moved on to surface ablation, first proposed by Lunan in 1992 and Melosh in 1993, Mirror Bees (media too concept), 4 month study supported by ESA ACT, study dynamics and mass estimates, solar pumped laser, if shoot are an angle – lose efficiency but avoid the plume of gas, cannot fire during the entire orbit, perturbations in orbit – required control authority, direct imaging with adaptive reflector, summary of two systems (laser and direct imaging), simulation of camera for observation, direct imaging: 1200 kg at TRL 2 including 40% propellant for the transfer (mirror diameter of 60m), laser (25% system efficiency) – mirror diameter 5m, done for Apophis, better to add more spacecraft than increase concentration ratio for same mirror size, various curves for warning times and size of bees, direct imaging required larger mirrors with adaptable shape, laser system requires smaller mirrors but more complex and requires efficiency above 20%, indirect laser pumping is more mature at his time, multiple spacecraft is better, many mirrors with low conversion factor appears to be more efficient than increasing the concentration factors of a few mirrors, question on impact of dust plume, experiments on simple rocks show that perhaps not 180 degrees of dust, Keith H.: has anyone done any calculations of absorption of that energy and verify the dynamics-concerned this is based on perfect gas models – when you have porous surfaces analysis may be more complicated, Melosh’s initial estimate indicates that effective at km sized body – will this work , perhaps competitive with 1km asteroid in terms of time to deviate and effect

- Apophis Encounter 2029: Differential Algebra and Taylor Model Approaches
Armellin, R.; Di Lizia, P.; Bernelli-Zazzera, F. (Politecnico di Milano, Italy)

Investigate differential algebra and Taylor models for 2029 Apophis encounters, , new algorithms (Improved Monte Carlo, and Close Encounter Algorithm), differential algebra: automatic differentiation technique, can be used for the nonlinear expansion of uncertainties of Apophis, third order expansion shows errors of 10 km in position, developed a DA Monte Carlo simulation, Close Encounter Distance (CED) Algorithm, a set of tools for NEO close encounters, attempt to develop faster and more efficient computational tools

- New Directions in Asteroid Deflection using Nuclear Explosives
Dearborn, D.1; Schultz, P.2; Ulrich, W1LLNL (United States); 2Brown University (United States); 3DTRA (United States)

No issues with Keith’s conclusions about nuclear option (only if other methods are not available), new work follows up with NASA 2006 report – proposed kiloton or sub-kiloton explosives on surface, you can break up asteroid (1 kiloton or less below breaking up 1 km size), reason to consider nuclear explosives – most mass efficient methods of transporting energy, plenty of tests, have been used in space, application and consequence (decades to impact: standoff/push), sources have been demonstrated, suitcase size types, LLNL have experience in making craters (290m x 100 m , ~200 m asteroid of Nevada tough), information on kinetic impactors, LLNL has 3-D codes, but use 2-D code (Langrangian Eulerian 2-D code), can put different types of properties (strength – water no strength, gravel-sand – force puts in pseudo force, can also put in porosity, never done that for meteorite in terms of crush curve, something that has porosity – early on you exceed crush pressure, want to take energy and distribute it, how much material are you really throwing out, Nevada tuff (density -= 1.9 g/cm^3), after you push something – you care about where pieces go, even when you do an impactor or nuclear – there is material thrown off – some small amount that is near original speed, approaches (decades to impact: standoff or low yield – surface emplacement), years to impact – high yield impact), standoff calculations - you need to heat a lot of mass, would like to do with neutrons versus X-rays, X-rays come in - heat first layer – that layer bleaches out – put in energy into a thin amount of mass, neutrons go right on in – for this >50% is absorbed in column density 48 g/cm^2, neutrons does not carry about mixture of elements (except for hydrogen), Neutrons – enhanced fusion, US stockpile weapons optimized yield/weight, would like something that provides a lot of neutrons – need a lot of fusion – US did that part of Plowshare program (peaceful nuclear explosions) – 35 tests, recent work looked at setting things at surface, with 0.1 kt at surface (0.38% of mass ejected, 1kt too much, 0.5 kt, 270 m body with 0.1 kt is too much – mass too low to depend know what you will get, no need for nuclear tests, real uncertainty is material properties of surface – when that energy is placed on surface how does the surface respond? Provide a dependable source to transport energy – would like to use things that were tested but now weaponized, when time scale is short if 50m is coming in then can covert to powder if just outside the moon, we have the duty to tell them what is possible.

- Using a Gravity Tractor to Help Mitigate Asteroid Collisions with Earth
Yeomans, D.K.1; Bhaskaran, S.1; Broschart, S.R.1; Chesley, S.R.1; Chodas, P.W.1; Jones, M.A.1; Sweetser, T.H.1; Lu, E.T.2; Schweickart, R.L.2 1JPL/Caltech (United States); 2B612 Foundation (United States)

Completed recently for B612, using the leverage of pre-impact close Earth approach to deflect a hazardous NEO with very modest amounts of energy, using slow NEO trim maneuvers to avoid primary and secondary impact possibilities, using rendezvous S/C images and tracking, 610 meter keyhole in April 13, 2029. Apophis test case is predicted to pass through the 2036 keyhole – impact 4/13/2036, assume it will impact for test case, launch in 2021 spacecraft, to S/C tracking and spacecraft acts as a gravity tractor, S/C again tracks Apophis, Feb. 14 2022 start tracking 580 x 15 km uncertainty ellipse, ends with 360x180 km ellipse after 60 days of tracking, GT placed 250 m from the asteroid’s center of mass along the asteroid velocity vector, five thruster configuration, takes 10kg / month for S/c hovering, 1000 kg S/C provided 1.14 x 10^-12 m/s^2 acceleration, 60 days of tracking moves Apophis on b-plane, Apophis is a unique case gets close to earth very close prior to impact, a few tens of percent could likely take advantage for gravity tractor, secondary keyholes are cm to one meter, primary keyhole is 610 m wide, secondary keyholes are more dense to primary keyhole, safe harbor could be established at zeta + 2.5 km (safe harbor around keyhole), examine the risk corridor during a slow deflection moves slowly, assume a KE impactor for beta = 2, m = 2400 kg, V = 5 km/s, if done in April 2022, deflection is 200 km change, by far the most important requirement of any successful mission campaign is warning time for carry out mitigation mission, Apophis unusual since close approach prior to impact, a pre-impact close approach multiples the effect tof earlier deflection, a deflection to avoid impact just needs to move out of keyhole, gravity tractor is a high precision procedure, GT could provide a trim maneuver

Panel Discussion

Dave Morrison: agnostic when it come to nuclear or non-nuclear, need to take into account spacecraft transportation, what is doable if you had a choice between the two methods,

Dearborn: If you were doing the standoff approach, question on altitude (putting our tons of neutrons) – could approach with fast speed, would prefer if UN passed law that all asteroids are rounds, adjust standoff time so you have right face of asteroid, “physics package” of about 100 lbs – put a seeker to reduce speed (not that much mass)

K. Holsapple: What is the uncertainty ellipse, question of getting to the right place, would want something there ahead of time

Dave. M.: No one has looked at nuclear deflection option reaching options

Alan Harris: getting caught with Apophis, Apophis is slow with the return, rendezvous with Apophis is ok, average RMS velocity is 15-20km/s, would encourage non rendezvous options (potentially proximity fuze option)

Exactly how precise time is for your detonation?
Keith H.: how accurately do you know where you are so you can have proximity fuze, radar fuze have fast timescales,

Fly multiple fast flybys, should not too focused on single flight mitigation options,

Dearborn: Aerospace did a scenario approach of hypothetical, every launch window advocated sending several options, launch them so approach at different times to see effect was sufficient

Rusty S.: Need to do a system level cost effectiveness analysis, ultimate questions- how do we best spend funds, if we look at cost effectiveness, it seems intuitive that if he takes Alan Harris size/freq. dist, most productive things I can do is to accelerate second generate of survey to the point that the unknown residual of any size NEO decreases as rapidly as possible, when invest in 2nd generation search, largest NEOS become known earliest. If we say nuclear device is needed for large object, three basic reasons for nuclear: big object at any time, smaller object getting to it rapidly – both of those disappear for all but comets – third issue does not disappear – geopolitical procrastination, geopolitical community cannot make a decision in time to use a non-nuclear method – one remain case that will not go away – ultimate geopolitical (audience claps)

K. H: most politically method is likely to be the one to be stuck with since politicians cannot decide to do anything else

Dearborn: if Tunguska sized object is going to fall in central Africa – people at UN would talk all the way down, if it were hitting for Paris – one nation might choose to do something, was not proposing to spend more money, what is the number one thing – send more money to Don Yeomans, if you want something to learn about asteroids – you need an impactor mission (Don Quixote),

Michel, P: comments by the people – most of people who want deflection mission, there is public fear of using weapons, may scientists do not want to come to this conference since they think it implies nuclear weapons, we have to be careful how we pronounce this

Dearborn: I do hear things that may scientists nuclear devices for excavation, information should be in the room, in the meeting with Tom Gehrles, the deflection dilemma – nuclear explosive – may indeed be facing larger risk to build such a system and have it ready – one needs to think very carefully whether the cure may be worse than the disease (SALT treaties, Chinese declared that they were not ready to turn in nuclear weapons for asteroids – never mind their weapons were not designed for asteroids)

Dearborn: did not advocate building anything

K.H: if anyone says we need to test a nuclear weapon, we need to understand response of the asteroid and can do that with an impactor

Clark C.: the porosity has been discussed a lot today, do not think asteroids look like piles of dust, Don David and Chapmen coined rubble pile, a rubble pile consists of hugh pieces to fine stuff (Itokawa), how are you going to kinetic or nuclear – how you are going to model the response of such a heterogeneous nody

K. H: ultimately how nigh is your event compared to the grains? Less effect than you might image (question of size scale)

Dave M.: comments on Rusty’s argument, statistically is we do survey or not, we are here that something could happen, you cannot just say statistically we cannot worry, a couple of people say nuclear is the system of choice, would think kinetic impactor is surely more easy to do – but several people said nuclear

Dearborn: if you can do it another way then do another way

K.H.: just a question of mission design, if you can do it with an impactor then do it with an impactor, perhaps solar collectors could be competitive – maybe could reach further,

Nothing like a deadline to focus, as soon as we do, everything kind of resolves, you always want a backup plan, nuclear will become less of a political liability

Alan Harris: let us not build it until we need it

K.H.: at some point someone would want to being up biggest “gun”

If you repeat the Tunguska event today, cost of real estate (300-400 M Euros over an unpopulated area) pay for a survey program,

Dearborn: with Tunguska like event, today the population is 12.5 people per square km, every few hundred years 25,000 dies, in an actuarial sense that is also the cost, with regard to where they put money, U.S./China/Russia have nuclear weapons for their own reasons – working their way down – at that point can extend out response time, keep nuclear weapons for political considerations and not for stopping asteroids,

Alan Harris: 20,000 per mean event, median = 0

A.Glavez: surprised debate is so polarized, you need several options, whenever this kind of things come, you have to have this knowledge, important to have working on a sustainable way

D. Izzo: for Apophis nukes may not the solution, coming up with different ideas

Michel, P: useful for having a demonstration mission like Don Quixote

K.H.: The engineering/mission questions are those that can be tested, what we do know for sure if we impact at certain velocity, deep impact (beta well over 100-200 perhaps), even calculations come up with ejecta velocities of beta of 30, need to know beta better, if we can hit it,

Michel, P.: we need a test

P. Gatterson: political leaders are ok are estimating risk, bit of fear mongering to talk about the cure is worse than the disease, even if you have a preference against using nuclear weapons, that is not prohibition against using it. Would add to Rusty’s case: you choose a softer touch approach and you fall back on redundancy but at least you thought through, not advocating a test mission.

27 April 2009

DoD TableTop Exercise on Planetary Defense Online

A new report from the U.S. DoD on a recent tabletop exercise looking at NEO scenarios is online. Here is the abstract

Natural Impact Hazard (Asteroid Strike) Interagency Deliberate Planning Exercise After Action Report. Directorate of Strategic Planning, Headquarters, United States Air Force. PDF 0.3 MB. 107 pages.

Abstract: Air Force Future Concepts and Transformation Division (AF/A8XC) hosted a Natural Impact Event Interagency Planning Exercise, 4 Dec 2008, in Alexandria, Virginia. Twenty Seven Subject Matter Experts from across US Government, including DOD, DOE, DOS, DHS, NASA, and NSC participated in a single day tabletop exercise to explore whole of government response to an impending asteroid strike. The specific scenario involved a mythical asteroid, 2008 Innoculatus. It was a binary asteroid consisting of a 270m rocky rubble pile projected to strike the Gulf of Guinea and a 50m metallic companion asteroid projected to strike in the National Capital Region (NCR). The scenario was selected to maximize exposure to the diversity of threat (variation in size, composition, land/water strike), stress both national and international notification, and provide useful pre-planning should an actual effort need to be mounted against the asteroid Apophis when it has a small probability to pass through a gravitational keyhole in 2029 and perhaps return to strike the Earth seven years later in 2036. Participants were broken into two teams. The first team focused on disaster response and was told the asteroid was discovered 72 hrs from impact. The second team focused on deflection/mitigation and was told the asteroid had been discovered seven years from impact, and to design a strawman deflection plan using existing capabilities. The major insights from this exercise are presented.

Link: Natural Impact Hazard (Asteroid Strike) Interagency Deliberate Planning Exercise After Action Report.

Link: NSS Planetary Defense Library

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

- Session 1 Discovery, Tracking, Characterization (Part 2)
Session Chairs: Don Yeomans, Lindley Johnson, Dave Lynch

- Other posters: Some interesting poster:
Canadian NEEOSAT, DLR AsteroidFinder is pat loaf on frsit compact satellite platform, Ball Aerospace, single spacecraft in Venus-like orbit (90% of all diameter objects within 7 years), Halo observatory for IEO (Interior Earth Objects) from KientX and NASA Ames.

- Asteroid Potential Impact Warnings
Chesley, S.R. (Jet Propulsion Laboratory, United States)

Potential warning times: unavoidable consequence of search programs, Pan-STARRS 1 (PS 1) impact warning forecasts, Astrometric errors and star catalog errors,
Warnings are unavoidable, initial probability will rise then drop as orbit is refined, certain number of impact warnings, at some point information becomes good enough for drop off, for Apophis highest peak was 2.7% impact probability - if continued without march 2004 observations - impact probability would have gone to 10%,

Pan-STARRS forecast, a simulation of 4 years PS1 survey (PS1 discovered 6500 NEAs, 1500 per year), 1557 sentry runs on 1135 objects, 17% of discoveries run, 45 days of CPU time (8 cores LINUX workstation, 1 week), 237 Sentry runs returned potential impacts (15%), 12 Torino Scale 1, 12 Palermo larger than -2)

Discovery rate has been declining, TS =1 about 1 per year now, PanSTARRS 1 will not create a little more TS = 1 events,

For 6-8 years seeing problems with astronomy, seeing a persistent problem with declination orbits (declination residuals), two possible causes (problem with asteroid dynamical model, problem with observations), Measurements are all pushed up in celestial frame, systematic errors in star catalogs

By 2008, 58M CCD based asteroid orbits observations (sources are different catalogs), compare to 2MASS catalogs (500 M stars), correct the astronomy from the MPC, take known catalog and apply to fit,

Apophis: Tholen/Nernardi released 33 observations, bias in data, adding de-biased pushes plane beyond the 2036 current keyhole, 2036 impact probability drops by a factor of 5 using approach, greatest shift in inclination, smaller along track shift, perhaps shift impact probability to less than 1 in million, Yarkovsky effect now getting important, starting to become important, detectable in 2011/2012 timeframe

Is PANStarrs 1 able to process data for 2008 TC3s?, operating in different mode, covers sky much less frequently, will not get 1-5 day warning, could see far enough to find them earlier, will not get orbit in 8 days,

- Impact Warning Times for the Next Generation of Asteroid Surveys
Chodas, P.W.; (Jet Propulsion Laboratory, United States)

How much warning time do we have? Define warning time as time at which impact probability goes past 50%, depend upon orbit uncertainties, many factors that affect IP (number/accuracy, geometry, apparitions, length of data arc, time of last observation before impact, close approaches, availability of radar observations), Use 1000 simulated impacts, numerically integrate over 50 year period, in study use various tools (PanSTARRS 1 model/LSST model, follow-up), long term discovery efficiency LSST should find about 90% of objects (after 10 years), Short term discovery efficiency also looked at (H = 20, 85% of objects found 1 year before impact, H=26, much smaller number), how long it would be between mean intervals, approximately internal of 300 years for H=26, Long term warnings (10 years) for H=26 only as 25-33%, at the large and medium sizes, long term warning point is keyed to discovery time, warning point is issued at object’s second apparition, LSST1 generated warning times 10-20% faster than PS 1. PS 1 and LSST not to be run concurrently, from Clark Chapman – suggest running with less than 50% chance (maybe 10% or 15), need to look at the costs for using these systems, if your goal is to find meteorites then meteorite surveys are more efficient, Alan Harris: follow-up is important - how does it work (amateurs?), Alan Harris: follow-up from PanSTARRs.

- Predicting the Apophis Earth Encounters in 2029 and 2036
Giorgini, J.1; Benner, L.A.M.1; Ostro, S.J.1; Nolan, M.C.2; Busch, M.W.3
1Jet Propulsion Laboratory/California Institute of Technology (United States); 2Arecibo Observatory (United States); 3California Institute of Technology (United States)

From Paper in Icarus in 2008, Apophis: albedo (0.33 +/- 0.08), diameter (270 m +/- 60 m), rotation (30.4 hours), 2011: next meaningful optical, 2013 next radar opportunity, 2021 another radar opportunity, 5.6 - 6.3 Earth radaii in 2029,

3 Arecibo campaigns, 18 months (2005-2006), small size, large distance - weak echos (0.19-0.27 AU), next image is 2-3 pixels, orbit solution improvement, 2029 (predicted encounter is 28,000 km closer to earth), using Standard Dynamical Model (SDM), for Apophis consider 6 systematic error sources in SDM for min/mass effects, SDM error (2029: 1600 km, 2036: 65 M km), Yarkovsky (-740 km in 2029, 30M km in 2036), solar radiation pressure error is similar magnitude as Yarkovsky, by 2013 should get the impact of the unmeasured parameters, 22 Earth radii alternation by all these other errors (by 2036), Predictability (mass, spin-pole, etc.) unkwnown,

SDM tends to mis-estimate impact risk, use a min/max effect to exclude threat, future mitigation must make change to account for all uncertainties.

- Panel Discussion

Alan Harris (the elder): Radar confirms Apophis is a slow rotator
David Morrison: thermal infrared impact?
Question from Russian researcher: What level should we get excited about (if anything is higher than 1 in million), what about rendezvous mission (probability more than 1%)
Question on how many current PHSs, within the next 200 years, have resonant returns? (Don Yeomans will answer in a later session)
How about deformation during a close approach)?

- Additional Poster Papers:
Some selected poster papers:
GRAVMOD: ESA Gravity Model for Asteroids and Comets, initiated in 2004 to develop models for gravitational modeling, Spitzer study for low perihelion NEAs, AsteroidFinder/SSB (DLR): first payload on SSB satellite platform, Comet Tempel 1 agrees with lab experiments (Comet Tempel 1 being as fully as Talcum power),

- Minor Planet Center Activities in the Next Generation of Search
Tim Spahr, (Smithsonian Astrophysical Observatory, United States)
Presented by Don Yeomans

6 people at MPC, Tim Spahr (management),
Duty of the MPS is to process every single provisional measurement of small bodies, 63 M observations, 460 k objects, 2 night objects (no orbit) and single night observations (10 M observations)

Most observations arrive as unidentified tracklets (2+ positions), all orbits are improved daily, new objects linked with other objects
All orbits, changed daily, NEOs > 24 hours, comets weekely, 6200 NEO objects, 937 NEOS H<18 (17.75), easily handle 25,000 objects per day, JPL/PISA use data for , NEO probability code (hybrid code), New Possible NEOs (50% score or higher), NEO confirmation pages for observers to look at (also uncertainty paths), NEOCP is 98% automatic, Pan-STARRS will be proving most data in batches or properly 2+ nights, DIGEST2, the probability code, being rewritten in C++ for distribution, WISE spacecraft source: 40 cm IR telescope, ~1000 NEOs, Main challenge is transitioning software to modern OS and database structure, MPC itself is in better shape with support from NASA, still a single center, potential a need for somewhere a center that is shadowing to main continuity in database,

- The Pan-STARRS Survey for Near Earth Objects
Granvik, M.; Wainscoat, R.; Jedicke, R.; Denneau, L. University of Hawaii (United States)

From the Institute of Hawaii, 4x1.8 m R-C teelscoprs, 7 degree FOV, 1.4 Gpixel camera, 700 square deg/night, automated data processing pipeline, first order correction for atmosphere, pushes 4 areas of technology, functional prototype (Ps1) PS1 will be operations in May 2009 on Hawaii, PS1 science consortium, NASA NEO program funds 15% of PS1 operations and MOPS, PS1 NEO survey (morning and evening sweet spot, Moving Object Processing System (MOPS) fully automated to MPC. Intital idea: take existing software, 4 images combined, remove static sky and obtain transients, MOPs 10 M objects. MOPS freely available, shared development with l LSST. Simulated 4 years PS1 survey (results in about 8k NEOs and 1900 PHOs, results in a t least 1 tracklet (24k NEOs, 6. 9 NEOs, ran 130,000 impactors over 100 year (2010-2110), PS1 starting in spring 2009, PS2: starting 2010, Ps4 construction to being after PS2 is ready, build 4 PS1 telescopes per year, PS16 ~ LSST, but /4th the cost, PS1 CCD has problem with the field factor – CCD only a few percent of field factor (88-89%), will attempt to , ~$260M (PS) / $320M (LSST)

- Detecting NEOs using LSST
Zeljko Ivezic (University of Washington, United States)

Need to go to H=24 for 90% completeness of NEOs under 140m in diameter, need to have larger telescopes, 1: 140m V ~25 in 15 sec (10 m class), Field of view of 5-10 degrees, data rate of 30 terabytes/night on the LSST, LSST in Chile - 8.4m, 3200 megapixle, large field of view of 3.5 degrees, 3 mirrors focusing into camera (need for $400M for development and $400 for operations for 10 years), Science drivers for LSST: dark energy/dark matter (10B galaxies), NEOs, time domain (gamma ray), and Milky Way (10B stars), LSST PHA survey - find 80% of NEO > 140m, 15% of time for PHA, PHA completeness reached 90% in 12 years for diameter > 140 m, LSST generates colors of objects, provides additional information than simple magnitude, correlation between color and albedo can be used to estimate size, LSST IOC by 2015, PHA objective met by 2027, effective cost of optimized NEO survey would be $120M, once per year there is a call to become partner organizations with LSST - open project that is open to involvement from international groups/individuals

Chapman: 30% chance of LSST catching 2008 TC3-like objects

- AsteroidFinder/SSB: A German Mission for the Search of IEOs
Mottola, S.1; Behrens, J.1; Börner, A.1; Gerene, S.2; Grundmann, J.T.1; Hahn, G.1; Hallmann, M.1; Kührt, E.1; Michaelis, H.1; Scheibe, K.1; Schmitz, N.1; Spietz, P.1; 1DLR (Germany); 2JAQAR (Netherlands)

Inner region of solar system is largely unexplored, IEO (Inner Earth Orbits ) or Atiras (10^3 have diameter > 100m), only 10 known IEOs (discovery about 1.2/year), why do this mission: inner region exploration, record of inner planets, small observatory in a cost effective platform, above atmosphere of ionosphere, AsteroidFinder is a response to DLR call for proposals for the national compact satellite program (#, orbits, size of NEOs/IEOs, detect space debris from LEO - secondary objective), compact satellite based on DLRSSB, quasi-polar low earth/sunsynch orbit - 650-700 km altitude), 25cm wide telescope, body mounted, no consumables, looked between Earth and Venus, dual launch configuration, focal length of 760 mm, aperture >400 cm^2, EMCCD image stabilization system, 4M pixel array, modeling the survey though the MISKA survey simulator - very conservative scanerio of around 10 discoveries per year (not full-time observation), international team going to Phase B (2013 launch, 1 year mission)

- IR Techniques to Detect and Characterize NEOs
Mainzer, A.1; Wright, E.2; McMillan, R.3; Eisenhardt, P.1; Trilling, D.4; Walker, R.5; 1Jet Propulsion Laboratory (United States); 2UCLA (United States); 3University of Arizona (United States); 4Northern Arizona University (United States); 5MIRA (United States)

- Remote Characterization of NEOs
Rick Binzel (MIT, United States / Paris Observatory, France)

Colors and related to NEOs, may help in develop correct albedo assumptions, asteroids grouped by color, Paper coming out new taxonomy extends from the visible region to 2.5 microns, asteroid taxonomy decoder ring, 42 spectral channels, colrs can also suggest albedo, strong correlation between color group and albedo, direct measurement of low albedo NEOs (so dark, at 1 AU become wamr enough to become visible in near IR, determine bulk physical properties, most meteorites are chondrite or stony iron,

Case study: Apophis: results are in current Issue of Icarus, data indicate that it is LL Chondrites meteorite due to matching, grain density 3.5 +/- 0.1 gcm^-3, 3.2 +/- 0.2 gcm^-3, porosity: 7.9 +/- 4.2%, for 270 m, mass estimate 3.3 +/-1.5, Look at pyramid, net stage of data comes from radar or spacecraft, assumed same overall porosity as Itokowa

2009 DD45: 30-50 m wide asteroid, obtained spectrum, Albedo 0.36, size was really 19 +/- 4 meters,

2008 TC3: F-type spectrum (carbon-rich object, low density, primitive if low albedo and hydrated), 2008 Tc3: carbon-rich anomalous, ureilite (new type of meteorite)
Lessons 1: basic characterization such as color and albedo, lesson 2: correlation between NEO and meteorite, nature holds surprises (2008 TC3)

- Radar Reconnaissance of Near-Earth Asteroids
Benner, L.; Ostro, S.J. (Jet Propulsion Laboratory, United States)

Arecibo and Goldstone are two planetary radars, Goldstone is 350 m in diameter, Arecibo is 20 times more sensitive than Goldstone but fixed, Goldstone 70 m in diameter (slew south and north), different transmitter frequencies, doppler range range (routinely achieve 1000 meters in asteroid size), radar detection of PHA secures its orbit, of ~1000 objects, several hundred can be lost, multiple apparition radar may improve accuracy of orbits (without radar Apophis IP higher by 3-4), 13 comets observed by radar, radar goes past coma of comet, Comet Tuttle (Harmon at Arecibo), radar image different from optical, radar image is a different projection, Itokawa radar image image did not change very much - shape model did not have enough detail, there is no such thing as typical NEO, shape for 4660 Nereu (E-Class asteroid) - accessible NEO, making regular radar observations, by using Yarkovsky effect we can estimate of object's mass, YORP effect (acceleration in object's spin) - directly measured, contact-binary shapes (10% of population) - objects are touching, non principal axis rotations, Mithra (interested rotating case), abundance of binaries (1 in 6 objects seen by Arecibo since upgrade), first triple system (2001 SN263), Near Earth Asteroid Surface Roughness Depends on Compositional Class, 1998 CS 1 (from Jan. 2009) - 1.2 km in diameter - can see small surface features) radar synergies with NEO tracking, characterization and human exploration, do we want to maintain radar observations, funding for Arecibo is in jeopardy, Arecibo has funding thourhg this year, NSF has not announced budget for the future, white paper will have support to keep Arecibo.

Steve Ostro Memorial Symposium, June 4 2009, JPL Von Karman Auditorium

Crimea radar does some data (no real-time analysis capability), bi-static observation, some intercontinental work with other telescopes

- Physical Characterization of Sub-Km NEAs: Low cost Mission Approaches
Morrison, D.1; Chartres, J.1; Coloprete, A.1; Genova, A.1; Jaroux, B.1; Johnson, R.1; Lemke,L.1; Williams, B.2; Chesley, S.3 1NASA Ames Research Center (United States); 2KinetX (United States); 3Jet Propulsion Lab (United States)+

Philosophical and historic perspective and a specific study (NASA Ames Study)

At the beginning, 1990s, we had to understand that there was an impact hazard, these kind of assessments were done by scientific approaches, Clark Chapman and Dave Morrison initially developed consequence charts, must do these studies for mitigation studies,

Second level, deal with mitigation based upon hazard itself, leads to 1 km or larger asteroids, these are very rare, next impact would not be these at 1 km, next generation surveys are looking at the objects wqith the greatest risk, 1-2 km impact is rare, still individually more at risk from large objects than the small objects, this is where we have been until the last few months...

Change of emphasis from the greatest hazard to the most likely event, "what is the next event to happen: will come up with different approach, many more crashes of small planes than of big planes (concern is the big ones), we have the capability to deal with more frequent events - political events will push us to dealing with those...

Work with other communities, do both of these at once, deal with greatest threat and most likely event, can we optimize advanced surveys, public and media demand that we deal with the smaller objects, we mus retain our primary focus on the largest threat (greatest potential to kill people), "faced with a cloud of mosquitoes and a deadly venomous snake, you would swat mosquitoes, but ignore snake at your peril"

Size matters, Eros as a million times less mass then then moon, Apophis as a million less mass than Eros...

What is the minimum spacecraft observations will make a major step in understanding asteroids, looking for a rendezvous, different from our previous spacecraft tours, a flyby of asteroid lasts less than 1 second, flyby not a useful thing to do (less important than radar), key measurements require rendezvous, place spacecraft around object, NASA Ames looks at Apophis mission, require simple instrumentation, doe snot emphasize mineralogy from spectral characterization, only be done up close is size/shape geology, shape density..

Looked at minimum size mission, minimum science and minimum cost, Ames mission study looked at ESPA ring variant, worked about one year at Ames with some NASA HQ, 20 month development, Feb. 2012, 3 month physical characterization, secondary payload, launch along with someone else, spend several months in Earth-moon space, with direct launch one year later, Nav camera/mapping camera/MIR camera/LIDAR/DHU, worked on LCROSS, multiple science products (including mass, shape, density, surface reflectance/temperature, topography, etc.), science ops for one year, ESPA ring, cost is $100M-$200M depending on launch options, partnering with other agencies, concept complete in 2008.

- Panel Discussion

Mexican and Chinese radar efforts are probably long lead items if at all
Spanish researcher talking about new techniques about daylight cameras that are recording bright fireballs (Spanish fireball network)
System designed to optimize to find small objects, what would you know about large systems (largely uncoupled), (Dave M.) when you look at the little ones you find ones that are close - does not save the world from previous impacts,
largest NEOs from inner asteroid belt, 1 meter sized object Yarkovsky can move your throughout the asteroid belt, meteorites sample a larger sample of the asteroid belt then asteroids that we see,
Chesley on Dave M.'s point: very substantial analysis - nothing really concrete on warning and that it is a serious problem, if you set up a system to catalog then you need to operate for decades or centuries (during that time frame, you will cataloged all of your impacts)
Dave M.: if we were to play our odds we would not be in this room, don't bother about these little ones, we are here because of the unlikely events, we would be remiss if we did not look through our data set to find large objects
Alan Harris: a survey is like fishing 0 you catch small in trying to get large ones
Keith Holsapple: what has risen to the top, we need to know what are the physical strength characteristics (need to prod it etc.) - really way to do that is a Don Quixote type mission (some applause for this), one group observes - other impact it, (want to ring its bell/map interior structure? - no) do not need to ping it (seismic might be data to guess), need to do large deformation and large shearing - whack it and watch the pieces,
Peter G.: if you hack it very hard, how does that complicate future mitigation? Keith was talking about a sample asteroid not one that was on the way
Clark Chapman: next generation survey, did not hear about probability or schedule, is it reasonable to assume that in 5-10 years that we will have a bigger survey (how viable are these it)? answer: LSST probability is between 0-1. LSST needs to be prioritized with other contenders, no means that LSST will happen ($50M in private,m $30-40M in public, NSF or someone else needs to award $240M), not obvious that is will happen - NEO driver would help to support project (not suggest that you should assume probability is 1), WISE is happening with mid IR information, NEOCAM is proposed (encouraged to try again)- discovery route is only available NASA program, LSST/WISE - not being paid for entirely by NEO people (we are a small group) to spread costs and benefits, PanSTARRS (PS1 and PS2) - PS4 still depends on funding,
low albedo objects are more difficult to be confident in your match with meteorites,
emissivity has to do with thermal properties (another piece of the puzzle), no emissivity classes for asteroids (yet), the more regolith you have the more chance you have surface is weathered (regolith plays a role)
Wondering if any of the missions looking at long period comet threat
Don Yeomans: if there were no surveys at all, LPC would be 1% of threat), now that the first generation surveys are finishing - asteroid threat is being reduced - LPC somewhere between 1-10% now, NEA are much bigger problem, pushing LPC threat off to the future generations, the more sky you survey the more you pick up LPC, Chesley: all sky survey like LSST good, but still the problem of trajectory prediction for LPCs. IR is ggod for comets (low abledo objects)
Ikari data: Japanese IR telescope currently in orbit (any "Warm" mission)?

What we as a panel should say in our recommendations?
L. Johnson: two things that NASA is doing that would be helped by white paper input, would provide valuable inputs (last day on National Research Council study), Decadal survey (once a decade study by scientific community), difficult to prioritize NEO work/research, what the panel and conference should say to be valuable inputs?
D. Morrison: only first style was scientific, how do we approach the NASA system with anything that approaches mitigation and not science?
L. Johnson: response to question above - how to get support in the NASA system, really is not a constituency that is int he NASA process that is there to talk about mitigation, only strong constituents, only is science community- stems from planetary science community - emphasis has to come out of the planetary science community, no other group that stands a chance, NEO community needs to talk to fellow planetary scientists,
Clark Chapman: Third decadel survey on astrophysics? LSST for astrophysics?
L. Johnson: perhaps an opportunity there but that path is more difficult, planetary decadal survey is a little easier, perhaps a combination of focusing on both decadal surveys
European SSA initiative: European side want a surface (exclude science as user), warning system to inform decision makers, wondering can you also have SSA awareness,
L. Johnson: talking about front end, strong statements from NRC and Decadal survey will feed into policy process, and then what OSTP states, strong feed to OSTP will help broaden attention paid to other elements
P. Gatterson: SSA given to DoD, for them to listen to this would be a defense science board study (OSTP can influence that, they can influence Defense Science board)
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