Before Pathfinder landed on Mars on Independence Day, scientists were realistic about their chances of receiving any useful information.
"It was very risky. Basically, we had $150 million worth of instruments that we put into airbags and threw at a planet. It bounced at least 16 times. We did not know if it would work," said James Bell, Cornell senior research associate in the Astronomy Department's Center for Radiophysics and Space Research late last week. Bell is part of the imaging team on NASA's Pathfinder mission to explore Mars. The Pathfinder lander and Sojourner, a robot rover scooting over the Martian surface, have been transmitting images and data since July 4.
The mood quickly became exuberant. "It was just spectacular," Bell said. "We were just ecstatic. Someone had a boom box and we were singing and dancing to the Beatles."
The engineers who run the mission are almost all in their 30s, Bell said, and that added to the excitement. "They're not like most previous NASA mission controllers, with crew cuts and pocket protectors. You'd be having lunch, talking about the latest grunge album, and you'd realize, 'Whoa, that's the mission manager.'"
It has been quite a success. The spunky little rover and lander, dubbed by NASA the Carl Sagan Memorial Station, has been transmitting data at 80 to 100 megabits per day -- while scientists expected a maximum of only about 5 to 10 megabits per day.
"That's good and bad," said Bell, who was in his campus office in the Space Sciences Building for a few days last week after spending the last two weeks at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "All the planning was for a small data volume. So we had no planning for this. You plan for a worst-case scenario, and this is completely the opposite end of the spectrum."
But it's a nice problem. It means scientists will be busy for the next year and more with data analysis and learning about the geology and chemical composition of the red planet.
It's become more business-like as the scientists settle into a routine. "We've only just now figured out the colors accurately," Bell said. "Everything's red."
Indeed, dust in the Mars atmosphere scatters sunlight in the red region of the spectrum, so even a purely white rock on the surface would appear pink. Even so, some rocks are red but a few could be white, said Bell, who is helping analyze the chemical composition of the planet. If analysis confirms that these rocks really are white, that could indicate limestone, which could mean that the atmosphere and environment were very different than they are now, even more conclusive evidence for the role of water in the Martian climate.
Another surprise: the Martian twin peaks and hills seen in the distance from the land rover. "The Viking images showed a flat horizon, and that's what we were expecting," Bell said. "But there are hills, ridges and crater rims nearby."
The diversity of soils also was a surprise. "There's dark red, bright red, pinkish. We don't know if this is related to the chemical composition or to the particle size."
The rocks themselves have unusual features, Bell said. "You can see structures that are indicative of layering in some rocks, as if they were stacked up. This would make sense if there were ancient, massive floods. A couple of rocks have veins going through them. Are they quartz? We just don't know yet."
The lander's chemical analyses have given scientists a big surprise, too. The first rock it analyzed -- Barnacle Bill -- has a high silica content, something not expected in typical volcanic rocks, called basalt. This is the type found in Hawaii that percolates up from the Earth's interior and is what scientists expected to find on the Martian surface.
Bell will be at the JPL again next week to continue to help analyze the findings. In the meantime, those interested in more information can visit a JPL mirror site at Cornell at http://mars.tc.cornell.edu/default.html.
For another story on James Bell, see our news release at http://www.news.cornell.edu/science/July97/Pathfinder.lb.html