[meteorite-list] Dawn Asteroid Mission Could Rise Again

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri Mar 17 13:26:37 2006
Message-ID: <200603171702.k2HH2LX08305_at_zagami.jpl.nasa.gov>

http://www.newscientistspace.com/article/dn8861-dawn-asteroid-mission-could-rise-again.html

Dawn asteroid mission could rise again
Kimm Groshong
New Scientist
17 March 2006

NASA has pried up what appeared to be the final nail in the coffin of
its Dawn mission to visit the two largest main-belt asteroids, Ceres and
Vesta.

According to an official NASA statement, associate administrator Rex
Geveden will be conducting a review of the decision to cancel the
mission "in light of additional information provided by NASA's Jet
Propulsion Laboratory".

Mary Cleave, associate administrator for NASA's science mission
directorate axed the mission on 2 March, having reviewed the findings of
an independent review board. NASA ordered the Dawn mission to "stand
down" in October 2005 to allow the board to assess its progress, after
technical problems and funding issues became apparent. NASA has never
been critical of the mission's science objectives.

When the mission was cancelled, Andrew Dantzler, director of NASA's
planetary science division, said the review board had found 29 major
issues that would have to be resolved before Dawn could proceed. He said
the mission was behind schedule and estimated to come in about 20%
over-budget.

NASA is granting no interviews with Geveden until the new review is
complete. The statement, dated 9 March, says: "The review is expected to
conclude within the next two weeks."

Planet forming

Lucy McFadden, a co-investigator for the Dawn mission based at the
University of Maryland in College Park, US, says she does not know what
the new information from JPL is. "But the fact that NASA is willing to
listen to our case is important," she told New Scientist.

She emphasises the importance of the mission's timing to achieve its
scientific goals. "The opportunity to visit, by spacecraft, both Vesta
and Ceres is limited to launching within the next year," she says.
"There is urgency to do this now for the sake of space science
exploration in the next decade." A new mission to both asteroids would
not be feasible again for 15 years, she says.

Furthermore, she says, findings from Hubble and ground-based telescopes
have made Ceres and Vesta more scientifically interesting in recent
years: "They're not just fragments of rocks. They're bodies that were
growing into planets and they have some characteristics of planets."

Water ice

It has long been known that Vesta has been heated in its history, but
recent spectroscopic results suggest there may also be small amounts of
water on the asteroid's surface.

In the case of Ceres, which scientists had always believed to be uniform
in composition, Hubble has found the asteroid may actually have a water
ice mantle that expands, inflating its shape. "That changes our whole
view of Ceres," she says.

So, McFadden concludes, it is compelling to go both Ceres and Vesta not
only because so little is known about the main asteroid belt, but also
because "they are precursors to our planets" and they may contain clues
about the formation of the solar system's inner planets.
Received on Fri 17 Mar 2006 12:02:21 PM PST