[meteorite-list] University of Maryland to Lead Another NASA Comet Mission (Deep Impact-DIXI)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Oct 31 12:58:45 2006
Message-ID: <200610311758.JAA29591_at_zagami.jpl.nasa.gov>

http://www.newsdesk.umd.edu/scitech/release.cfm?ArticleID=1361

For Immediate Release
October 30, 2006
Contacts: Lee Tune, 301 405 4679 or ltune_at_umd.edu

University of Maryland to Lead Another NASA Comet Mission

NASA announced today that it has accepted the University of Maryland
proposal to send the Deep Impact spacecraft on an
extended mission to get a close-up look at Comet Boethin.

The University of Maryland-led team that produced the spectacular Deep
Impact mission, which smashed an impactor into Comet Tempel 1 in July,
2005, hopes new information gathered from Comet Boethin will help
coalesce the vast array of new cometary information into solid ideas
about the nature of comets, how they formed and evolved and if they have
played a role in the emergence of life on Earth.

"As we try to interpret the larger meaning for all comets of our results
from Deep Impact at Tempel 1, we have realized more and more how
important is the variation from comet to comet," said Deep Impact leader
and University of Maryland astronomer Michael A'Hearn.

"Deep Impact's flyby spacecraft and payload are still healthy. We
propose to direct the spacecraft for a flyby of Comet Boethin in
December, 2008, to investigate whether the results found at Comet Tempel
1 are unique or are also found on other comets," he said.

"This mission is a very cost effective way to provide new results that
can be directly compared to the landmark Deep Impact findings as well as
with the results of Deep Space 1 and Stardust and the earlier results
from the numerous missions to Comet Halley."

Mission DIXI

The proposed new mission is called DIXI, which stands for Deep Impact
eXtended Investigation. DIXI will use the surviving Deep Impact
spacecraft and its three working instruments (two color cameras and an
IR spectrometer).

Comet Boethin is now inbound to the sun from its most distant point that
is nearly out to the orbit of Saturn, A'Hearn says. "At encounter, Comet
Boethin will be just outside Earth's orbit, closer to the sun than was
Tempel 1 (at the orbit of Mars) but about the same distance from Earth."

Like Deep Impact, DIXI will be a partnership between the University of
Maryland, NASA's Jet Propulsion Laboratory (JPL), and Ball Aerospace &
Technologies Corporation.

"One of the great surprises of comet explorations has been the wide
diversity among the different cometary surfaces imaged to date," said
A'Hearn, who will be principal investigator for DIXI. "Even on Tempel 1,
the comet we've imaged the best, there is shocking variability in its
surface. The comet's different surface types clearly have undergone
different histories."

A'Hearn says the data obtained from DIXI will also will help scientists
determine which characteristics of comet structure and composition are
primordial, reflecting conditions and processes that existed 4.5 billion
years ago when the solar system formed, and which are the result of
evolutionary forces (heating and cooling, impacts, etc.) that have acted
on comets since that time.

"Data from comets can help us to better understand the origin of the
solar system, as well as what role, if any, comets may have played in
the emergence of life on Earth," said Jessica Sunshine, a member of the
Deep Impact science team, who will be deputy principal investigator on
DIXI. "However, we first must know which cometary characteristics are
due to evolution and which are primordial."

Deep Impact Surprises

Deep Impact was the first large scale experiment ever conducted on a
comet. The Deep Impact flyby spacecraft made many surprising discoveries
on approach to Comet Tempel 1. These include an extremely fluffy
composition that largely insulates the interior from heat experienced by
the surface; frequent, natural outbursts; major differences in the
distribution of carbon dioxide and water; craters and other surprising
geological features; demonstration that the ice below the surface must
be evaporating (subliming) to water vapor, and the first detection of
ice (a very small amount) on a cometary nucleus.

"Since half the discoveries at Tempel 1 were from the flyby data taken
before impact, DIXI can return half the science of Deep Impact for much
less than 10 percent of the cost of Deep Impact," A'Hearn said. "From
the point of view of cost effective science, an extended mission such as
DIXI is unbeatable."
Received on Tue 31 Oct 2006 12:58:43 PM PST


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