From: LARRY KLAES (ljk4_at_msn.com)
Date: Wed Oct 24 2007 - 06:21:17 PDT
>From: David Morrison <david.morrison_at_nasa.gov>
>To: David Morrison <david.morrison_at_nasa.gov>
>Subject: NEO News (10/23/07) Marco Polo, Dawn, Workshop, Congress, DPS
>Date: Tue, 23 Oct 2007 14:55:45 -0700
>
>NEO News (10/23/07) Marco Polo, Dawn, Workshop, Congress, DPS
>
>
>ESA ANNOUNCES MARCO POLO SELECTION (October 21, 2007)
>
>The European Space Agency has announced the results of its Cosmic Visions
>2015-2025 call for proposals. Fifty space science missions for the next
>decade were proposed, with just seven selected. They range from X-ray and
>far-infrared observatories to planet finders and a near-earth asteroid
>sample return mission. These seven, together with the LISA gravitational
>wave observatory, will go ahead for further study in the next few years,
>and then two will be chosen for launch in 2015-2017. The asteroid mission,
>called Marco Polo, is a sample-return mission to a near-Earth object (NEO),
>Marco Polo would characterize a NEO at multiple scales and return a sample.
>If approved, the mission would study the origins and evolution of the Solar
>System, the role of minor bodies in the process, origins and evolution of
>Earth and of life itself. It would consist of a mother satellite which
>would carry a lander, sampling devices, reentry capsule as well as
>instruments. If approved, the mission would be implemented in collaboration
>with JAXA (perhaps combined with the Hayabusa Mark 2).
>
>The ESA NEA mission Don Quijote, which has been studied for several years
>as a technology demonstration, is shifting to an orbiter mission called
>SANCHO, with Spain taking the lead in its development. It might be possible
>later, however, to restore the small surface package and/or the high-speed
>impactor originally proposed for Don Quijote through partnerships with
>other space agencies.
>
>
>DAWN IS ON THE WAY TO VESTA AND CERES
>
>The Dawn spacecraft successfully launched at 7:34 am EDT on September 27,
>2007. On October 9, it successfully tested its ion propulsion system. With
>its solar electric propulsion operating, Dawn is set to travel over the
>next 8 years to Vesta and Ceres, the two largest maIn belt asteroids,
>orbiting each asteroid. Dawn is a NASA Discovery mission, with Chris
>Russell of UCLA as PI and JPL as managing NASA Center.
>
>Dawn will begin its exploration of asteroid Vesta in 2011 and the dwarf
>planet Ceres in 2015. These two icons of the asteroid belt have been
>witness to much of our solar system's history. By utilizing the same set of
>instruments at two separate destinations, scientists can more accurately
>formulate comparisons and contrasts. Dawn's science instrument suite will
>measure shape, surface topography, tectonic history, elemental and mineral
>composition, and will seek out water-bearing minerals. In addition, the
>Dawn spacecraft itself and how it orbits both Vesta and Ceres will be used
>to measure the celestial bodies' masses and gravity fields.
>
>Since Vesta and Ceres are not NEAs, we will not be covering this mission in
>any detail in NEO News. For regular updates, please check the Dawn homepage
>at (www.nasa.gov/mission_pages/news/dawn)
>
>
>WORKSHOP AT NASA AMES ON LOW-COST MISSIONS TO NEOS
>
>Summary from David Morrison, 22 October 2007
>
>The past weekend (October 20-21) more than 40 NEO scientists and engineers
>met for informal discussions of the potential of low cost missions to
>characterize NEOs. This workshop was part of series of informal weekend
>workshops hosted by Ames Center Director Pete Worden. The organizers were
>David Morrison (Senior Scientist, NASA Astrobiology Institute) and
>Stephanie Langhoff (Ames Chief Scientist), assisted by Organizing Committee
>members Erik Asphaug, Dan Durda, Bob Farquhar, and Pete Klupar. The
>workshop agenda was structured to bring together science and engineering
>communities who have a common interest in small missions but rarely talk to
>each other.
>
>The workshop agenda blended three major themes: (1) The importance of
>characterizing small NEOs and the kinds of science measurements that need
>to be made. (2) How to get to the targets: populations, orbital dynamics,
>direct vs. gravity-assist trajectories, opportunities for secondary
>payloads and missions of opportunity. (3) Low-cost missions: spacecraft,
>instruments, proximity operations, propulsion, landers, and impactors.
>Fifteen-minute papers covered the above topics, with plenty of time for
>discussion. The final afternoon was devoted to interactive discussions,
>organized around three key questions that the workshop participants could
>explore in smaller breakout sessions, on (1) impactors, (2) rendezvous and
>orbiter missions, and (3) landers. Sample return was considered outside the
>possible range for small missions, defined here as those costing under
>$100M.
>
>The workshop consensus was that small (low cost) missions to NEOs make
>sense. Since a major objective is to sample the diversity of this
>population, multiple small missions are cost-effective. At this stage of
>our knowledge, we can select the most accessible targets, which can be
>reached with modest launch vehicles, or in many cases as secondary payloads
>or missions of opportunity. The most powerful general exploration approach
>is with orbiting or rendezvous spacecraft. Impactors used in cooperation
>with other missions are potentially able to explore interior structure, and
>it may also be possible to achieve simple landings within the "small
>mission" cost cap. In all these cases, a program of NEO missions can be
>developed using either secondary payload opportunities or Minotaur-class
>launch vehicles, so long as we select the targets (as opposed to the
>asteroids selecting us).
>
>
>CONGRESSIONAL HEARING RESCHEDULED TO NOVEMBER 8
>
>The Congressional hearing on NEO surveys (originally planned for October
>11) has been rescheduled for November 8. The hearing before the House
>Subcommittee on Space and Aeronautics will tentatively include the
>following witnesses: Jim Green (NASA HQ), Scott Pace (NASA HQ), Don
>Yeomans (JPL), Rusty Schweickart (B612), Don Campbell (Cornell/Arecibo),
>and Tony Tyson (LSST). Further information including opportunities to
>listen on-line will be found at the Committee website
>(http://science.house.gov/).
>
>
>NEOS AT DPS MEETING
>
>The 2007 meeting of the Division for Planetary Science of the American
>Astronomical Society was held in Orlando October 7-12, with about 800
>planetary scientists attending. Asteroids and comets were remarkably
>prominent at this annual meeting. Not counting the Kuiper Belt, the program
>lists 171 papers (oral and poster) on comets and asteroids, rather evenly
>distributed among NEOs, Main Belt Asteroids, and Comets. Also, 10 out of 35
>oral sessions were on comets and asteroids. These included two "special
>sessions" on the first day of the meeting dealing with NEAs: "What's next
>with NEO searches" and "YORP Observed!".
>
>The session on "NEO Searches" was organized by Lindley Johnson (NASA HQ)
>and Don Yeomans (JPL). The program was:
>- Lindley Johnson: The state and future of NASA's NEO program
>- Robert Jedicke: The Pan-STARRS PS1 survey
>- Steven Chesley: Asteroid impact monitoring: Status and predictions
>- Paul Abell et al.: Piloted Missions to NEOs via the CEV
>- Donald Yeomans: NEO Lessons Learned
>- Steven Larson et al.: Current ground-based surveys for NEOs
>- Edward Wright: Space infrared observations of NEOs
>- Zelljko Ivezic: LSST's NEO survey capabilities
>- David Morrison: Role of NEO characterization missions
>
>The YORP (the Yarkovsky-O'Keefe-Radzievskii-Paddack) effect is a torque
>that can modify the rotation rates and axial tilt of small bodies via the
>combined effects of incident solar radiation pressure and the recoil effect
>from non-isotropic thermal radiation from the object. This effect can be
>seen in the alignments of spin vectors for members of asteroid families,
>and it is emerging as an important effect for spinning up asteroids to
>create binaries and for the long-terms evolution of asteroid orbits. While
>the YORP effect has been discussed theoretically for many decades, it had
>not been observed directly. The first clear detection is from optical
>monitoring of NEA 2000PH5, which has recently been given the name 54509
>YORP. The Japanese Hayabusa mission has also observed this change in spin
>for the small NEA Itokawa.
>
>--
>+++++++++++++++++++++++++++++++++++++++++++
>
>NEO News (now in its thirteenth year of distribution) is an informal
>compilation of news and opinion dealing with Near Earth Objects (NEOs) and
>their impacts. These opinions are the responsibility of the individual
>authors and do not represent the positions of NASA, the International
>Astronomical Union, or any other organization. To subscribe (or
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>please see the website http://impact.arc.nasa.gov. If anyone wishes to copy
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>please include this disclaimer.
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