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Mars Pathfinder Mission Status
July 25, 1997
1:30 p.m. Pacific Daylight Time
Mars Pathfinder celebrated its three-week anniversary on the surface of Mars today, with all spacecraft systems, science instruments and rover activities continuing to go exceptionally well.

On this Martian day, Sol 21, Earth rose at 10:48 p.m. PDT July 24 and Sunrise occurred at 1:53 a.m. PDT today.

The science team finished analyzing alpha proton X-ray spectrometer data from the rock nicknamed "Scooby Doo," the third rock measured by the rover since rolling off its ramp on July 5. ("Barnacle Bill" and "Yogi" were the first two rocks to be measured.) "Scooby Doo," of interest to scientists because of its light color, has a chemical signature very similar to other soils measured at the Pathfinder landing site. However, initial analysis shows that it contains slightly higher amounts of calcium and silicon.

Data returned during successful communications sessions last night indicated that the lander and rover remain in excellent health, reported Guy Beutelschies, Pathfinder flight director for Sol 21.

Sojourner performed a "self-guided" traverse today, receiving a minimum of instructions from Earth before driving off to find its own way to the next rock. Up until now, Sojourner has relied on detailed instructions and "way points," or X-axis and Y-axis coordinates, to find its way to the next rock target.

Today's 3-meter (10-foot) excursion, however, involved only two sets of way point instructions and an additional command to "find the rock." Sojourner used its own hazard avoidance system to locate the two way points, as it usually does, but then relied only on its laser light beams to find the next rock and line up with it. By 11 a.m. PDT, Sojourner had stopped just 25 centimeters (10 inches) in front of "Souffle," the next rock to be studied.

The rover will begin making measurements of "Souffle" on Sol 22, using its alpha proton X-ray spectrometer.

Meanwhile, atmospheric and meteorological data on the temperatures and density of the Martian atmosphere continue to be received during daily telecommunications sessions. Data stored onboard Pathfinder last week, while the flight computer was automatically resetting itself, were returned on Sol 21.

The lander camera snapped images of the disturbed soil near the rock called "Lamb," and photographed three more rocks: "Half Dome," "Shark" and "Pumpkin."

The Earth set today -- Sol 21 -- at 12:24 p.m. PDT. The Sun set at 2:46 p.m. PDT.

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