Rob R. Landis, et al Paper on Human NEO Mission on ScienceDirect

The study of a Human NEO Mission (done by several folks at NASA) was recently published online by ScienceDirect for the Journal Acta Astronautica. Here is the reference

"Piloted operations at a near-Earth object (NEO)"
Rob R. Landisa, Paul A. Abellb, David J. Korsmeyera, Thomas D. Jonesc, and Daniel R. Adamod

Available online 9 June 2009.

Abstract:

In late 2006, NASA's Constellation Program sponsored a study to examine the feasibility of sending a piloted Orion spacecraft to a near-Earth object. NEOs are asteroids or comets that have perihelion distances less than or equal to 1.3 astronomical units, and can have orbits that cross that of the Earth. Therefore, the most suitable targets for the Orion Crew Exploration Vehicle (CEV) are those NEOs in heliocentric orbits similar to Earth's (i.e. low inclination and low eccentricity). One of the significant advantages of this type of mission is that it strengthens and validates the foundational infrastructure of the United States Space Exploration Policy and is highly complementary to NASA's planned lunar sortie and outpost missions circa 2020. A human expedition to a NEO would not only underline the broad utility of the Orion CEV and Ares launch systems, but would also be the first human expedition to an interplanetary body beyond the Earth–Moon system. These deep space operations will present unique challenges not present in lunar missions for the onboard crew, spacecraft systems, and mission control team. Executing several piloted NEO missions will enable NASA to gain crucial deep space operational experience, which will be necessary prerequisites for the eventual human missions to Mars.

Our NEO team will present and discuss the following:

• new mission trajectories and concepts;
• operational command and control considerations;
• expected science, operational, resource utilization, and impact mitigation returns; and
• continued exploration momentum and future Mars exploration benefits.

Link: ScienceDirect reference

Agenda for Upcoming "Asteroid–Comet Hazard – 2009" Conference (September 21 – 25, 2009, St. Petersburg, Russia)

Agenda is up for the upcoming Asteroid–Comet Hazard – 2009 conference to be held from September 21 – 25, 2009, St. Petersburg, Russia. On Friday, September 25 they have a session on NEO mitigation. Here is the specific program for that session:

Session 8. Investigations of NEOs in situ. Counteraction NEO Hazard

9:00–9.30
A. Harris (Space Science Institute).
Estimating the NEO population and impact risk: past, present and future.

9:30–10:00
M. A’Hearn (Department of Astronomy of University of Maryland).
Deep Impact and deflection of NEOs.

10:00–10:15
A. Bar-Nun, D. Laufer, I. Pat-El (Department of Geophysics and Planetary Sciences of Tel-Aviv University).
The structure of Comet Temple 1 from Deep Impact and Laboratory Experiments.

10:15–10:30
R. Landis, D. Korsmeyer (NASA Ames Research Center), P. Abell (NASA Johnson Space Center of Planetary Science Institute), D. Adamo (Trajectory Consultant), T. Jones (Association of Space Explorers).
Robotic precursors & piloted missions to near-Earth objects: a scientific and planetary defense rationale.

10:30–11:00
V. Pol’, А. Simonov (S.A. Lavochkin Scientific-Technology Association of Federal Space Agency), L. Rykhlova (Institute of Astronomy of RAS).
Reconnaissance and tracking mission to the asteroid Apophis.

11:30–11:45
V. Ivashkin, (M.V. Keldysh Institute of Applied Mathematics, RAS, Moscow, Russia, ), C. Stikhno, (S.A. Lavochkin Scientific-Technology Association, FSA, Khimki, Russia).
A study of the orbit correction of the asteroid Apophis

11:45–12:00
V. Pol’, A. Simonov (S.A. Lavochkin Scientific-Technology Association Association of Federal Space Agency).
Possibility of delivery of counteraction means to the threatening asteroids.

12:00–12:30
W. Huebner, D. Boice, S. Chocron, A. Ghosh, R. Goldstein, J. Mukherjee, W. Patrick, M. Tapley, J. Walker (Southwest Research Institute), P. Bradley, P. Giguere, J. Guzik, J. Keady, C. Plesko, K. Wohletz (Los Alamos National Laboratory), L. Johnson, (NASA Headquarters).
The engagement space for countermeasures against PHOs.

12:30–13:00
C. Maccone (International Academy of Astronautics of Italy).
Description of a NASA study to deflect hazardous asteroids.

13:00–13:30
A. Zaitsev (Non-profitable Partnership “Planetary Defense Center”), A. Koroteev, B. Liaschuk, S. Popov (K.E. Tsiolkovsky Russian Academy of Cosmonautics).
Rocket-space means of echelon of short-term reaction of the Planetary Defense System.

15:00–15:15
V. Emelyanov, Yu. Merkushev (Central Scientific-Research Institute for Mechanical Engineering).
Project parameters and efficiency of the space-based system for the warning about falls of small sized celestial bodies, moving along the collision trajectories.

15:15–15:30
N. Makhutov (A.A. Blagonravov Mechanical Engineering Research Institute of RAS), V. Puchkov (Russian Ministry for Civil Defense, Emergencies and Disaster Relief), A. Zaitsev (Non-profitable Partnership “Planetary Defense Center”).
About measures on minimization of damage from collisions with asteroids and nuclei of comets.

15:30–15:45
Z. Milan Ilitz (Serbia).
Rotational mass driver – an efficient NEO deflection concept.

15:45–16:00
V. Legostaev, V. Lopota, V. Siniyavskiy (S.P. Korolev Rocket and Space Corporation “Energia”).
On the feasibility of using nuclear power propulsion units in the program to establish Earth protection against the threat of asteroid or comet impact.

16:00–16:15
E. Kührt, S. Mottola, G. Hahn (Institute of Planetary Research of German Aerospace Center), J. Behrens, P. Spietz, S. Gerene, J. Grundmann, M. Hallmann (Institute of Space Systems of German Aerospace Center), H. Michaelis, A. Börner, K. Scheibe (Institute of Robotics and Mechatronics of German Aerospace Center).
Asteroid finder − a space-based search for IEOs.

16:45–17:00
J. Smulsky (Institute of Earth's Cryosphere of RAS), Ya. Smulsky (Institute of Thermophysics of RAS).
Evolution of the Aphophis orbit and possible use of the asteroid.

17:00–17:15
A. Zaitsev, A. Klapovsky (Non-profitable Partnership “Planetary Defense Center”).
About the approach to formation of international-legal bases of ensuring planetary defense.

Link: Program "Asteroid–Comet Hazard – 2009" Conference

Link: Conference website

Upcoming Meeting of U.S. National Academies: " Review of Near-Earth Object Surveys and Hazard Mitigation Strategies" Project

The next meeting (3rd meeting) of the U.S. National Academies Review of Near-Earth Object Surveys and Hazard Mitigation Strategies will be held from August 10-11, 2009 in Massachusetts.

Review of Near-Earth Object Surveys and Hazard Mitigation Strategies
August 10, 2009 - August 11, 2009
J. Erik Johnson Woods Hole Center
314 Quissett Ave.
Woods Hole, Massachusetts

If you would like to attend the sessions of this meeting that are open to the public or need more information please contact:

Contact Name: Rodney Howard
Email: rhoward@nas.edu
Phone: (202) 334-3477

Agenda:Preliminary Draft Agenda

August 10, 2009
10:00 am Meeting Convenes
5:00 pm Meeting adjourns

August 11, 2009
9:00 am Meeting convenes
5:00 pm Meeting adjourns

Link: U.S. National Academies Project Page: Review of Near-Earth Object Surveys and Hazard Mitigation Strategies

Link: August 10-11, 2009 Meeting Page

JPL Update: Triple Asteroid System Triples Observers' Interest

Radar imaging at NASA's Goldstone Solar System Radar on June 12 and 14, 2009, revealed that near-Earth asteroid 1994 CC is a triple system. Image Credit: NASA/JPL/GSSR

From the article:

Radar imaging at NASA's Goldstone Solar System Radar on June 12 and 14, 2009, revealed that near-Earth asteroid 1994 CC is a triple system. Asteroid 1994 CC encountered Earth within 2.52 million kilometers (1.56 million miles) on June 10. Prior to the flyby, very little was known about this celestial body. 1994 CC is only the second triple system known in the near-Earth population. A team led by Marina Brozovic and Lance Benner, both scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif., made the discovery.

1994 CC consists of a central object about 700 meters (2,300 feet) in diameter that has two smaller moons revolving around it. Preliminary analysis suggests that the two small satellites are at least 50 meters (164 feet) in diameter. Radar observations at Arecibo Observatory in Puerto Rico, led by the center's director Mike Nolan, also detected all three objects, and the combined observations from Goldstone and Arecibo will be utilized by JPL scientists and their colleagues to study 1994 CC's orbital and physical properties.

The next comparable Earth flyby for asteroid 1994 CC will occur in the year 2074 when the space rock trio flies past Earth at a distance of two-and-a-half million kilometers (1.6 million miles).

OF the hundreds of near-Earth asteroids observed by radar, only about 1 percent are triple systems.

Link: JPL AsteroidWatch Article

Article: "Mystery of Mars Missing Magnetic Field -Was It Destroyed by Asteroid Impact?"

From the article...

Planetary magnetic fields are created by massive molten metal currents within the planet's core. A flowing current creates a magnetic field, even when the current is massive volumes of charged liquid metal moving under the influence of temperature gradients (convection) - in fact, especially then. But magnetic analysis of Martian sites by Berkeley researchers show that the red planet's protective field was switched off half a billion years ago, and now some scientists say they know why.

John Hopkins University scientists have calculated that a period of massive asteroid impacts, known to have happened around the same time, could not only have massively impacted on the surface Deep Impact-style (with all the atmospheric alteration and great-big-crater-making that entails) but added enough energy to the planet to heat up the outer layers of the planet.

Without the huge temperature difference between the core and mantle, the mega-magnetic dynamo convection currents would be switched off - and unable to start up again when things cooled down. Remember, planetary core behavior is still carrying on from when the planets first formed - as far as they're concerned the whole "crust" thing and all life as we know it is just a cooling scum on the surface. If you break something from back then you just don't have the juice to start it up again.

Without the magnetic field Mars is defenseless against the radiation that constantly pours in from space (never mind the Fantastic Four, the only superpower cosmic rays'll give you is decomposition). Earth is thought to have survived the same space-bombing because of our superior size, with our dynamo maybe stuttering a little but - very importantly - not stopping.

Link: Article

"Did Mars's Magnetic Field Die With a Whimper or a Bang?"
Zala
ScienceNOW
30 April 2009

Link: ScienceNow Article

Article: "Lunar Crater Stats Indicate Hidden Population of Asteroids"

From the article...

Many moons are locked in synchronous rotation with their mother planets. Examples include the Galilean moons of Jupiter, Neptune's moon Triton and our own Moon.

In the 80s and 90s astronomers noticed that the distribution of craters on these objects was asymmetric: they were more heavily cratered on their leading hemispheres which makes sense since it seems obvious that these areas should be struck more often.

It wasn't until 2003, however, that the same asymmetric crater distribution was measured on our Moon. Now Takashi Ito at the National Astronomical Observatory in Japan and Renu Malhotra at the University of Arizona have asked an interesting question. of the data. Can the asymmetric distribution of craters on the Moon be explained by the known distribution of near Earth asteroids that are thought to have caused them? Their answer is a cautious "no".

To properly explain the crater distribution, Ito and Malhotra say some other factor must have been involved. One possibility is that we simply haven't seen all the craters yet: the ongoing lunar mapping missions may help on that score.

Another idea is that the Earth's tidal forces tear Earth-crossing asteroids apart, creating a higher number of impacts than might otherwise be expected.

But the most exciting and potentially worrying possibility is that there exists a previously unseen population of near Earth asteroids that orbit the Sun at approximately the same distance as the Earth. These have gone unnoticed because they are smaller or darker than other asteroids, say Ito and Malhotra.

"More complete observational surveys of the near-Earth asteroids can test our prediction," they say.

"Lunar Crater Stats Indicate Hidden Population of Asteroids"
03 August 2009

Link: Technology Review Article

Abstract:

Asymmetric impacts of near-Earth asteroids on the Moon
Authors: Takashi Ito, Renu Malhotra
(Submitted on 17 Jul 2009)

Abstract: Recent lunar crater studies have revealed an asymmetric distribution of rayed craters on the lunar surface. The asymmetry is related to the synchronous rotation of the Moon: there is a higher density of rayed craters on the leading hemisphere compared with the trailing hemisphere. Rayed craters represent generally the youngest impacts. The purpose of this paper is to test the hypotheses that (i) the population of Near-Earth asteroids (NEAs) is the source of the impactors that have made the rayed craters, and (ii) that impacts by this projectile population account quantitatively for the observed asymmetry. We carried out numerical simulations of the orbital evolution of a large number of test particles representing NEAs in order to determine directly their impact flux on the Moon. The simulations were done in two stages. In the first stage we obtained encounter statistics of NEAs on the Earth's activity sphere. In the second stage we calculated the direct impact flux of the encountering particles on the surface of the Moon; the latter calculations were confined within the activity sphere of the Earth. To represent NEAs' initial conditions, we considered two populations: one is the currently known NEAs, and the other is a synthetic population created by debiasing the orbital distribution of the known NEAs. We find that the near-Earth asteroids do have an asymmetry in their impact flux on the Moon: apex-to-antapex ratio of 1.3-1.4. However, the observed rayed crater distribution's asymmetry is significantly more pronounced: apex-to-antapex ratio of ~1.67. Our simulations suggest the existence of an undetected population of slower (low impact velocity) projectiles, such as a population of objects coorbiting with Earth.

Link: Abstract: "Asymmetric impacts of near-Earth asteroids on the Moon"

Link: Paper: Asymmetric impacts of near-Earth asteroids on the Moon [PDF]

Article: "The Puzzle Of The Half Comet-Half Asteroid"

From the article...

In 1996, astronomers identified an extraordinary object orbiting the Sun between Mars and Jupiter in the region best known for its asteroids. And yet this body, called 133P, defied description: it had the orbit of an asteroid and yet was emitting dust like a comet.

Clearly, this is a rare object. After centuries of observation, not a single other object in the asteroid belt has burped gas and dust in the same way.

So how could this have got there? According to Henry Hsieh at Queen's University, Belfast in Northern Ireland, there can be only two explanations. The first is that 133P is a comet that has somehow recently become trapped in an asteroid-like orbit. This would have required a hugely unlikely combination of gravitational kicks from other planets as the comet travelled into the solar system from the Kuiper Belt or Oort cloud.

"The Puzzle Of The Half Comet-Half Asteroid"
05 August 2009

Link: Technology Review Article

Abstract:

The Hawaii Trails Project: Comet-Hunting in the Main Asteroid Belt
Authors: Henry H. Hsieh (Queen's University, Belfast)
(Submitted on 31 Jul 2009)

Abstract: The mysterious solar system object 133P/(7968) Elst-Pizarro is dynamically asteroidal, yet displays recurrent comet-like dust emission. Two scenarios were hypothesized to explain this unusual behavior: (1) 133P is a classical comet from the outer solar system that has evolved onto a main-belt orbit, or (2) 133P is a dynamically ordinary main-belt asteroid on which subsurface ice has recently been exposed. If (1) is correct, the expected rarity of a dynamical transition onto an asteroidal orbit implies that 133P could be alone in the main belt. In contrast, if (2) is correct, other icy main-belt objects should exist and could also exhibit cometary activity. Believing 133P to be a dynamically ordinary, yet icy main-belt asteroid, I set out to test the primary prediction of the hypothesis: that 133P-like objects should be common and could be found by an appropriately designed observational survey. I conducted just such a survey -- the Hawaii Trails Project -- of selected main-belt asteroids in a search for objects displaying cometary activity. I made 657 observations of 599 asteroids, discovering one active object now known as 176P/LINEAR, leading to the identification of the new cometary class of main-belt comets. These results suggest that there could be ~100 currently active main-belt comets among low-inclination, kilometer-scale outer belt asteroids. Physically and statistically, main-belt comet activity is consistent with initiation by meter-sized impactors. The estimated rate of impacts and sizes of resulting active sites, however, imply that 133P-sized bodies should become significantly devolatilized over Gyr timescales, suggesting that 133P, and possibly the other MBCs as well, could be secondary, or even multigenerational, fragments from recent breakup events.

Link: Citation: The Hawaii Trails Project: Comet-Hunting in the Main Asteroid Belt

Link: Paper: The Hawaii Trails Project: Comet-Hunting in the Main Asteroid Belt [PDF]

Mars Opportunity Rover Meets Possible Meteorite

Thanks to Leonard David for noticing the two newest images from the Mars Rover Opportunity below.

Image Credit: NASA/JPL-Caltech

Image Credit: NASA/JPL-Caltech

Image Credit: NASA/JPL-Caltech

Image Credit: NASA/JPL-Caltech

Link: JPL News Site

Link: SpaceFlightNow Article

Rusty Schweickart's Comments on 2009 Jupiter Impact

From Alan Boyle's article "Lessons from Jupiter's black eye", selections follow:

For years, [Apollo Astronaut and B612 Foundation leader Rusty] Schweickart and his colleagues at the B612 Foundation and the Association of Space Explorers have been urging the United Nations to take a more formal approach to assessing cosmic threats. Because the effects of an impact could be global, the deliberations about what to do in case an impact should have an international scope as well.

The first step is to identify potential threats: Just in the past week, Schweickart and others sent a letter urging the Australian government to restart funding for a near-Earth object search in the Southern Hemisphere. The government cut support to Spaceguard Australia in 1996, and since then asteroid-watchers have worried about the huge "blind spot" in their coverage area. (Fortunately, Australian amateur astronomers such as Anthony Wesley, who first spotted the Jupiter impact, have helped fill the gap.)

"Australia is arguably the most advanced country in the hemisphere," Philip Chapman, NASA's first Australian-born astronaut, was quoted as saying in The Australian. "Failure to contribute to the international effort is grotesquely irresponsible."

Schweickart told me in a follow-up e-mail that the jury is still out on the precise cause of the latest Jupiter impact:

"I think that the comet claim is simply a default position and perhaps a carryover from the Shoemaker-Levy 9 comet impact. Since no one saw it prior to impact, who knows whether it was a comet or asteroid. In my view, it's very much more likely to be an asteroid impact, simply due to the much higher population.

"As to why no one saw it prior to impact or knew it was going to impact… that’s pretty easy. Any asteroids that don’t come near Earth are difficult to see. The likelihood of spotting a 1-kilometer (this was probably not larger than that… most likely smaller) asteroid which circulates from the main belt out to halfway between Jupiter and Saturn is vanishingly small. The only way we’d have to know about this ahead is if it happened to be a near-Earth asteroid with an aphelion [maximum distance from the sun] greater than Jupiter's distance. That's a very small percentage of the near-Earth asteroid population.

"Still… any evidence of current impacts on any other body help to emphasize that it's only a matter of time till it's our turn. So the more the merrier!"

Link: MSNBC Cosmic Log article

JPL/B612 Paper on Apophis Keyholes

From JPL Paper: D.K. Yeomans, S. Bhaskaran, S.B. Broschart, S.R. Chesley, P.W. Chodas, T. H. Sweetser, R. Schweickart, "Deflecting a Hazardous Near-Earth Object," 1st IAA Planetary Defense Conference: Protecting Earth from Asteroids, 27-30 April 2009, Granada, Spain.

Updated JPL paper (response to U.S. NRC committee and presented at the 2009 Planetary Defense Conference). From the JPL NEO website:

This short report on Near-Earth Object (NEO) hazard mitigation strategies was developed in response to a request for information by the U.S. National Research Council's Space Sciences Board on December 17, 2008 and for the Planetary Defense Conference that took place 27-30 April 2009 in Granada Spain. Although we present example simulations for specific techniques that could be employed to deflect an Earth threatening NEO, our primary goal is to discuss some of the general principles and techniques that would be germane to all NEO deflection scenarios. This report summarizes work that was carried out in early 2009 and extends an earlier, more detailed study carried out in late 2008.

Link: JPL NEO Website News Item on Updated Apophis Keyhole Analysis (PDC Paper)

Link: JPL NEO Apophis Whitepaper (April 2009)