PUBLIC INFORMATION OFFICE 
JET PROPULSION LABORATORY 
CALIFORNIA INSTITUTE OF TECHNOLOGY 
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011

Contact:  Franklin O'Donnell

FOR IMMEDIATE RELEASE                         October 23, 1995

SCIENCE PAYLOAD SELECTED FOR COMET LANDER

     Science investigations designed to image the surface of a 
comet close up and determine its exact chemical and mineralogical 
composition have been provisionally selected by NASA and the 
French space agency, to be carried out early next century on a 
comet lander named Champollion.

     Slated for launch aboard the international Rosetta mission, 
Champollion and a similar comet lander named RoLand, to be 
provided by a German-led consortium, will be the first spacecraft 
ever to land on one of these ancient clumps of icy rubble.  
Champollion is managed by the Jet Propulsion Laboratory.

     Planetary scientists believe that comets were the primary 
building blocks for the outer planets of the solar system. 
Cometary bombardment also may have provided a significant 
fraction of the atmosphere, oceans and organic materials of Earth 
when it was a young planet.

     The overall scientific objective of the Rosetta mission is 
to produce a global picture of a comet called Wirtanen, including 
its shape and composition, the nature of the volatiles that it 
spews out, and the comet surface phenomena that contribute to 
this process.

     The mission is named after the Rosetta Stone, an ancient 
Egyptian tablet discovered near the town of Rosetta in 1799 that 
provided a major key to the translation of Egyptian hieroglyphic 
writing.  Jean-Francois Champollion of France, for whom one of 
the Rosetta mission comet landers is named, played a large part 
in deciphering it.

     "The new knowledge about comets that Rosetta and Champollion 
promise to return will help us decipher important clues about the 
earliest stages of the formation of our solar system, just as the 
Rosetta Stone did with ancient Egyptian hieroglyphics," said Dr. 
Wesley T. Huntress, associate administrator for space science at 
NASA Headquarters in Washington, D.C.  "The most intriguing 
potential result from Champollion's investigations is the 
possible presence of complex organic molecules, which would tell 
us whether these precursors of life might have been brought to 
Earth by comets."

     Rosetta will be the first spacecraft to orbit a comet.  It 
represents the next major step in cometary science, following 
several recent reconnaissance flybys of comets by other 
international spacecraft.  Rosetta is the third cornerstone 
mission in the European Space Agency's long-term space science 
program called Horizon 2000.

     After its scheduled launch aboard an Ariane 5 vehicle in 
January 2003, the Rosetta spacecraft will perform gravity-assist 
flybys of Mars and Earth, and then rendezvous with comet Wirtanen 
in August 2011.  It will deploy the Champollion and RoLand 
surface landers about one year later.  Two asteroid flyby 
encounters also are planned for about halfway through the 
mission.

     The selected Champollion experiments incorporate a number of 
new technologies, including high-density, three-dimensional 
electronics, an advanced infrared spectrometer, active pixel 
imaging sensors with on-chip electronics, an advanced gamma-ray 
sensor, and a miniaturized, low-power gas chromatograph/mass 
spectrometer.

     A suite of a dozen cameras will provide Earth-bound 
scientists with their first close-up look at the surface of a 
comet.  One set of cameras, to be provided by Dr. Jean- Pierre 
Bibring of the Institut d'Astrophysique Spatiale in Orsay, 
France, will create stereo images of the landscape surrounding 
the lander.  A second camera set supplied by Dr. Roger Yelle of 
Boston University, Boston, MA, will photograph the surface close 
to the lander.  An even closer look will be generated by a 
microscope, also supplied by Yelle, which should reveal 
individual grains in the comet nucleus.

     Organic molecules, which may provide clues to the origin of 
life on Earth, will be identified by a gas chromatograph/mass 
spectrometer to be contributed by a group led by Dr. Paul Mahaffy 
of NASA's Goddard Space Flight Center, Greenbelt, MD.  
Determining the chemical composition of the comet itself is the 
task of an international consortium headed by Dr. Claude d'Uston 
of the Centre d'Etude Spatiale des Rayonnements in Toulouse, 
France.  They will use a gamma-ray spectrometer to measure the 
radiation generated from inside the comet by the cosmic rays that 
bombard it continuously.

     The strength, density and temperature of the comet surface 
will be measured by probes placed on spikes driven into the 
surface.  These spikes, to be provided by Dr. Thomas Ahrens of 
the California Institute of Technology, will also serve to anchor 
the spacecraft firmly to the comet and prevent it from drifting 
off into space.

     The scientific investigators for the provisionally selected 
instruments are based at 10 U.S. universities, three NASA field 
centers, three other U.S. laboratories, 10 French institutes and 
nine institutes in other countries.

      A radio sounding tomographic experiment that would produce 
a CAT scan-like, three-dimensional image of the comet nucleus is 
under consideration as an additional Champollion investigation, 
if financial and technical resources can be made available. It 
would be provided by Dr. Wlodek Kofman of the Centre d'Etude des 
Phenomenes Aleatoires et Geophysiques, St. Martin d'Heres, 
France.

     Full confirmation of the Champollion instrument payload is 
anticipated in about one year, after a formal review and 
endorsement by the ESA Space Program Committee in February 1996, 
and verification by NASA and the French space agency, Centre 
National d'Etudes Spatiales (CNES), that the selected 
investigators are able to accommodate changes required to 
increase instrument collaboration and decrease their costs.

     JPL manages the Champollion project for the Solar System 
Exploration Division of NASA's Office of Space Science, 
Washington, D.C., and the CNES Scientific Program Division, 
Paris. CNES will contribute several key elements of the mission, 
including its telecommunication subsystem, batteries, spacecraft 
separation mechanism, and its ground-based control system.

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10-23-95
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