NASA Headquarters, Washington, DC
Jet Propulsion Laboratory, Pasadena, CA
September 26, 1997
"The lander and rover performance continues to be nothing short of extraordinary," said Brian Muirhead, Mars Pathfinder project manager at NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA. "We have proven that we know how to design robust robots to operate in the hostile environment of Mars."
The rover has just completed its last alpha proton X-ray spectrometer study for a while, taking compositional measurements of a rock nicknamed Chimp, located just behind and to the left of an area scientists call the Rock Garden. Once data from the spectrometer have been retrieved, Sojourner will begin a 164-foot (50-meter) clockwise stroll around the lander to perform a series of technology experiments and hazard avoidance exercises.
Meanwhile, the Pathfinder lander camera is continuing to image the Martian landscape in full-resolution color as part of its goal to provide a "super panorama" image of the Ares Vallis landing site. Each frame of this panorama is imaged using 12 color filters plus stereo.
"The super pan will be our biggest and best imaging data product," Muirhead said. "It is made up of 1 gigabit (1 billion bits) of data, of which we've received more than 80 percent. Given our limited downlink opportunities, we should have the full image by the end of October."
The 22-pound (10.5-kilogram) rover has survived 10 times longer than its primary mission design of seven days, while the lander has now been operating 2.5 times longer than it was originally expected to operate, according to Richard Cook, Mars Pathfinder mission manager.
Both vehicles are solar-powered, but carried batteries to conduct night-time science experiments and keep the lander warm during the sub-freezing nights on Mars. Normal usage has fully depleted the rover's non-rechargeable batteries, limiting it to daylight activities only. The lander battery, which packed more than 40 amp-hours of energy on landing day, performed perfectly during the 30-day primary mission, but is now down to less than 30 percent of its original capacity.
"We expected to begin seeing this type of degradation on both vehicles and, of course, designed both the lander and rover to operate without batteries altogether," Cook said. "If everything else continues to operate properly, we could continue conducting surface experiments for months."
About once every two weeks, the lander battery is used to perform some night-time science experiments, he added. The primary activity is acquiring meteorological data and images of morning clouds, as well as images of Mars' two small moons, Phobos and Deimos.
Despite the lack of battery power, the rover has continued taking successful spectrometer readings during the day. In the next two weeks, engineers will drive the vehicle back to a magnetic target on the ramp from which Sojourner first touched Martian soil.
"This analysis of the dust on the ramp magnet is a very important science measurement," noted Dr. Matthew Golombek, Mars Pathfinder project scientist. "The results should give us a clue about how all this magnetic dust was formed."
The next media briefing on science results from Mars Pathfinder is tentatively scheduled for Wednesday, October 8, at 1 p.m. ET at JPL.
The Mars Pathfinder mission is managed by the JPL for NASAÕs Office of Space Science, Washington, DC. The mission is the second in the Discovery Program of fast track, low-cost spacecraft with highly focused science goals. JPL is a division of the California Institute of Technology, Pasadena, CA.
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