[meteorite-list] Hubble Assists Rosetta Comet Mission

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:29:51 2004
Message-ID: <200309051522.IAA11833_at_zagami.jpl.nasa.gov>

Paris, 5 September 2003
European Space Agency
Press Release
N° 55-2003

EMBARGOED UNTIL 21:00 CEST
Hubble assists Rosetta comet mission

Results from the NASA/ESA Hubble Space Telescope have played a major role
in preparing ESA's ambitious Rosetta mission for its new target, comet
67P/Churyumov-Gerasimenko. Hubble has been used to make precise
measurements of the size, shape and rotational period of the comet.
Information that is essential if Rosetta is to rendezvous with the comet
and then drop down a probe, something never before attempted and yet a
major step towards elucidating the origins of the solar system.

Observations made by Hubble in March this year revealed that comet
67P/Churyumov-Gerasimenko (67P/C-G) is approximately five by three
kilometres in size and shaped like a rugby ball. ESA mission scientists
were concerned about the exact size of the solid nucleus, which is needed
to adapt the mission to the comet's gravity. "Although 67P/C-G is roughly
three times larger than the original Rosetta target, its highly elongated
shape should make landing on its nucleus feasible, now that measures are
in place to adapt the lander package to the new scenario," says Dr
Philippe Lamy of the Laboratoire d'Astronomie Spatiale in France, who is
presenting the Hubble results on comet 67P/C-G today at the annual meeting
of the Division for Planetary Sciences of the American Astronomical
Society in California, USA.
 
Mission scientists began looking for an alternative target when the
Rosetta mission's launch date was postponed. The delay meant that the
original target comet, 46P/Wirtanen, was no longer easily reachable. But
scientists did not have enough information on the back-up comet, 67P/C-G,
and sought data from the largest telescopes. Using a technique developed
over the past decade by Philippe Lamy, Imre Toth (Konkoly Observatory,
Hungary), and Harold Weaver (Johns Hopkins University Applied Physics
Laboratory, Laurel, USA), the team snapped 61 Hubble images of comet
67P/C-G over a period of 21 hours on 11 and 12 March. Hubble's Wide Field
Planetary Camera 2 isolated the comet's nucleus from the coma, the diffuse
gas surrounding the nucleus, quickly providing the figures required. The
telescope showed that the nucleus is ellipsoidal and measured its rotation
rate at approximately 12 hours.

Rosetta's launch is currently planned for February 2004, with a rendezvous
with the comet about 10 years later.

# # #


Notes for editors
The team is made up of P. L. Lamy and L. Jorda (Laboratoire d'Astronomie
Spatiale, France), I. Toth (Konkoly Observatory, Hungary), and H.A. Weaver
(Johns Hopkins University Applied Physics Laboratory). The movie
simulation of the Hubble results is provided by Mikko Kaasalainen
(University of Helsinki, Finland) and Pedro Gutierrez (Laboratoire
d'Astronomie Spatiale, France).

The observations were made possible through a special programme approved
by the Director of the Space Telescope Science Institute, S. Beckwith.

For more information, please contact:
Philippe Lamy
Laboratoire d'Astronomie Spatiale, France
Cellular: +33-630-14-92-33
E-mail: lamy_at_astrsp-mrs.fr

Lars Lindberg Christensen
Hubble European Space Agency Information Centre, Garching, Germany
Tel: +49-89-3200-6306 (089 within Germany)
Cellular (24 hr): +49-173-3872-621 (0173 within Germany)
E-mail: lars_at_eso.org

Ray Villard
Space Telescope Science Institute, Baltimore, MD, USA
Tel: +1-410-338-4514)
E-mail: villard_at_stsci.edu

Michael Buckley
Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
Tel: +1-443-778-7536
E-mail: michael.buckley_at_jhuapl.edu
Received on Fri 05 Sep 2003 11:22:55 AM PDT