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Mars Pathfinder Mission Status
July 7, 1997
1 p.m. Pacific Daylight Time
Moderate weather yesterday, temperatures hovering around minus 76 degrees Fahrenheit, pressure about 6.8 millibars, steady light winds blowing from the southeast. Afternoon temperatures reached about 10 degrees Fahrenheit. The forecast for today: 10 degrees Fahrenheit, cooling overnight to about minus 105 degrees Fahrenheit.

A little extreme for an Earthly weather report? Perhaps, but with that, scientists on the Mars Pathfinder mission today presented the first weather report from Ares Vallis, an outflow channel on the surface of Mars.

Four days into surface operations, the Mars Pathfinder lander, rover and instruments are performing perfectly and returning a wealth of new data on the rocks, soils and atmosphere of Mars.

"The site is everything we hoped it would be," said Dr. Matthew Golombek, Pathfinder project scientist, at a 10 a.m. PDT press briefing. "We are finding more and more surprises as we look in detail at the rocks and terrain."

Images presented this morning included the first photograph of the lander taken by the rover. The image showed final retraction of the airbags in a very high, puffy clump that blocked most of the lander from view.

Meanwhile, the lander's Imager for Mars Pathfinder (IMP) camera has provided a new perspective on rocks and hills on the Martian horizon now that it is deployed on its mast and photographing the site at an elevation of 1.0 meters (3.2 feet) above the lander, said Dr. Peter Smith, IMP principal investigator from the University of Arizona.

Another new image presented this morning showed Sojourner Truth, the 23-pound rover that has begun to explore rocks around the landing site, as it was gathering data overnight on "Barnacle Bill." This rock, which was about 36 centimeters (1.2 feet) from the rover after it exited the lander, is thought to be about 8- to-10-inches tall, Smith said, and has a very distinctive surface that looks almost as if it is covered with barnacle-shaped objects.

"Here we have proof that Sojourner sort of nestled up and kissed Barnacle Bill," Golombek said as the photograph was presented.

"We have also received data from the rover's first soil experiment. The APXS (alpha proton X-ray spectrometer) is working perfectly," Golombek continued. "However, because we started taking data earlier in the day than we originally planned, the temperatures on Mars were warmer than the detectors liked and we have a bit of noise in the spectra. The team needs an extra day to try to figure out how to subtract that noise out."

The science team said a full chemical analysis of both the Martian soil and Barnacle Bill would be reported at tomorrow's 11 a.m. PDT press briefing. Meanwhile, Sojourner will travel to a larger rock later today, called "Yogi," and study the composition of the soil around it using the alpha proton X-ray spectrometer. Several scientists have commented that a smooth depression of soil around the rock resembles a moat.

Looking south at a pair of sloping hills, called "Twin Peaks," that are about a mile away, Smith pointed out new observations made possible by the fully deployed IMP camera. A depression in the landscape in front of the peaks suggests the presence of a channel. "This is actually a channel back behind those rocks, we're on the edge of a channel," he said.

A high resolution close-up of the Martian soil near the base of the lander also revealed a texture perfectly preserved in the Martian environment. Dr. Jim Bell of Cornell University explained the calibration targets that are used to achieve the true color of the Martian landscape. Color variations allow scientists to identify different types of minerals that are present in the environment. The bright reddish color of the soil, for example, points to the presence of oxidized iron in surface materials.

"The surface of Mars is rusting," Bell said. "We don't know when or how fast it's rusting, but we hope to find these things out. Not all of the surfaces are the same, though. There's lots of diversity and variation in the landscape. We can see some surfaces that are much less red, for example, and more consistent with volcanic rocks."

Building on comments made yesterday by Dr. Ronald Greeley (Arizona State University) about the evidence for floods in this region, Dr. Michael Malin, an interdisciplinary scientist, said the floods were so catastrophic that they would have filled up the Mediterranean basin here on Earth. Evidence, he said, can be seen in the variety of rocks, sediments and "puddles" left in the Martian soil that materials from the highlands were swept into this flood basin.

A full color, 360-degree panorama of the Pathfinder landing site will be presented at tomorrow's 11 a.m. press briefing, as will data about the composition of the Martian soil and Barnacle Bill.

Briefings are carried live on NASA TV, which is available on GE-2, transponder 9C at 85 degrees west longitude, vertical polarization, with a frequency of 3880 MHz, and audio of 6.8 MHz.

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