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Pathfinder continues extended mission Sojourner has survived 10 
times longer than its primary mission design

By DIANE AINSWORTH

     After 83 days of atmospheric, soil and rock studies, NASA's 
Mars Pathfinder lander and rover are continuing extended mission 
activities that will take the rover on its longest trek yet and 
the lander into new photographic endeavors.
     "The lander and rover performance continue to be nothing 
short of extraordinary," said Project Manager Brian Muirhead. "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 measurements of a rock 
nicknamed Chimp, located just behind and to the left of 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 nighttime 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 nighttime 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 week, 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 Pathfinder Project 
Scientist Dr. Matthew Golombek. "The results should give us a 
clue about how all this magnetic dust was formed."
     Recent images and movies continue to be posted on the Mars 
Pathfinder home page at http://marsweb.jpl.nasa.gov . 
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