PUBLIC INFORMATION OFFICE
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Mars Pathfinder Mission Status
August 1, 1997
6 p.m. Pacific Daylight Time
A wealth of new information about Martian weather and atmosphere was acquired by the Pathfinder lander on the 27th and 28th days of surface operations in the Ares Vallis outflow channel on Mars.

Data are showing that daily temperatures do not vary much, but minute-by-minute temperatures can fluctuate dramatically, reported Flight Director Rob Manning. Atmospheric pressures can also change significantly within a matter of minutes. Scientists think some of these variations may be caused by small dust devils that can be whipped up by a gust of wind.

The flight team has been taking advantage of longer downlink sessions over the last several Martian days to acquire as much weather data as possible. Regular weather measurements will be limited in the days ahead due to the lander's limited battery power. A two-day shutdown of lander operations to recharge the battery will occur on Sunday and Monday, Aug. 3-4.

Summer temperatures remain in the same range. This morning's low was minus 75 degrees Celsius (minus 103 degrees Fahrenheit) , while highs rose to minus 15 degrees Celsius (5 degrees Fahrenheit). Winds were blowing lightly from the south and swinging around from the northwest during the day.

The rover continued its trek south today after undergoing a temporary delay. Yesterday the vehicle detected a jam in its left front wheel and autonomously backed up to free the pebble from the cleats in its stainless steel wheels. Today Sojourner marched about 4 meters (13 feet) to the south.

"Using waypoints specified the day before, Sojourner stopped, spun about and carefully backed up and onto a small dune named Mermaid today," Manning said. "This afternoon she continued to back up onto the dune and then lowered the alpha proton X-ray spectrometer onto the dune. Tonight the rover will collect elemental spectra of this interesting feature."

The lander and rover returned more than 60 megabits of science and engineering data on Sols 27 and 28. "This data included yet another rover traverse movie and a series of photometric strips that will allow scientists to precisely gauge the optical properties of key features near the lander," Manning added.

On this Martian day, Sol 28, Earthrise occurred at 3:29 a.m. PDT and sunrise followed at 6:32 a.m. PDT. The Earth set at 5:02 p.m. PDT and sunset occurred at 7:20 p.m. PDT.

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