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

Contact: Diane Ainsworth                                                

FOR IMMEDIATE RELEASE                                                October 30, 1995

SCIENCE INSTRUMENTS SELECTED FOR 1998 MARS MISSIONS


       An extremely lightweight camera and a variety of instruments designed to study daily weather patterns and the icy south pole on Mars have been selected by NASA officials to fly aboard an orbiting spacecraft and lander in late 1998.

       Known as the Mars Surveyor '98 Orbiter and the Mars Surveyor '98 Lander, the robotic missions will enable detailed scientific studies of the planet's atmosphere, climate, meteorology and surface volatiles such as water ice and frozen carbon dioxide. The lander will be the first mission ever sent to the poles of Mars, where it will settle on terrain that appears to consist of alternating layers of clean and dust-laden ice.

       "These investigations will collect data that is fundamental to a better knowledge of the climate of Mars, both in the past and in the present," said Dr. Wesley T. Huntress Jr., associate administrator for Space Science at NASA Headquarters. "Landing in a polar region is particularly interesting and exciting. These areas probably hold the key to understanding what appear to be quasiperiodic climate fluctuations on the planet over thousands or even hundreds of thousands of years, and the nature of the orbit of Mars makes this our only opportunity to send a mission to a pole during the next decade."

       The orbiter will carry an advanced technology optical camera called the Mars Surveyor '98 Orbiter Color Imager, to be provided by Dr. Michael Malin of Malin Space Science Systems, Inc., San Diego. With a total mass of only 1 kilogram (2.2 lbs), the camera system is less than 1/20th the mass of the Mars Observer camera spare, also provided by Malin, that will fly aboard NASA's Mars Global Surveyor spacecraft, scheduled for launch in November 1996.

       The camera consists of two elements: a wide-angle camera that will acquire daily weather maps of Mars with a surface resolution of 0.8 kilometers up to 7.2 kilometers (0.5 miles to 4.5 miles), and a medium-angle camera with a resolution of 40 meters (131 feet) that will study alterations in the planet's surface over time due to changing atmospheric conditions and winds.

       The orbiter also will carry an atmospheric instrument called the Pressure Modulator Infrared Radiometer (PMIRR), which was selected for flight in July. PMIRR will measure temperature profiles of the Martian atmosphere and monitor its water vapor and dust content.

       Malin Space Science Systems Inc. will provide another lowmass camera for the Mars '98 lander, called the Mars Surveyor '98 Descent Imager. It will produce wide-angle views of the Martian surface beginning about 10 seconds after the lander's parachute has been deployed, at approximately 8 kilometers (5 miles) in altitude, until its landing. These pictures will be used to provide a larger geographic context for local landforms around the landing zone, and to help tie together images from the orbiter with the exact landing site.

       Once on the surface, the lander will power up an integrated science payload to be supplied by Dr. David Paige of the University of California at Los Angeles. Known as the Mars Volatile and Climate Surveyor, this payload achieves a mass of just 17 kilograms (37 lbs) through the use of common electronic components and other shared subsystems.

       The payload includes a mast-mounted imager to take stereo photos of the surrounding landscape; a 2-meter (6.5-foot) robot arm that will dig up and deliver surface samples to a thermal and evolved gas analyzer to determine their content of ice and frozen carbon dioxide; and a mast-mounted meteorological package with sensors to record atmospheric pressure, temperature and winds. During its planned 86-day surface mission, the lander's robot arm will attempt to dig trenches in the icy polar soil and then use a small arm-mounted camera to transmit close-up pictures of any stratified layers.

       "Like the exposed walls of the Grand Canyon on Earth, these layers should reveal a fascinating record of gross fluctuations in the Martian environment, telling us more about why a planet that appears to have been so wet in the past is so cold and dry now," said Huntress.

       NASA is continuing discussions with the Russian Space Agency (RSA) about the possibility of Russia supplying a science instrument for the lander, in addition to hardware that the RSA is contributing for the PMIRR orbiter instrument. Options for the lander include a laser-ranging device that measures atmospheric dust and haze or an electromagnetic sounder that would map soil density variations and possible subsurface water. A final decision on these lander instruments should be made by the end of November, Huntress said.

       The Mars '98 Orbiter and Lander are scheduled for separate launches aboard Med-Lite expendable launch vehicles in December 1998 and January 1999, respectively. The missions are part of NASA's Mars Surveyor program, a 10-year series of cost-capped missions to Mars featuring two launches every 26 months.


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10/30/95 DEA
#9577