Roving about the Red Planet
"I just love this stuff, love it," says Steve Squyres, the project's lean, hyperkinetic overseer of the science instruments and Cornell University planetary sciences professor. Sleeves rolled up, he hustles down the stairs between a large science team meeting and an intimate confab over data. The electrically driven wheels on the machines and the arrays of transmitters and mineral analysis tools were designed for three months' work. By now, fears were that worn parts, the cold of a Martian winter, dust on the solar panels, or all three would shut them down for good. Hard of hearing and a bit arthritic, Spirit indeed is showing its age--a balky front right wheel requires three times normal current to get it turning, and a radio receiver drifts off tune in the cold. For both rovers, solar power is under 40 percent what it was at landing. In mid-September, the rovers may be put on standby, using as little power as possible, parked on slopes as sunny as can be found. The cold is apt to crack the optics of one instrument, rendering it useless. But project manager Jim Erickson now says the two could revive by October and run into September next year.
"Trust the vehicles." Nobody knows how far into the hills Spirit may go, nor whether Opportunity will live out its days in deep Endurance Crater. Squyres constantly exhorts his teams to "trust the vehicles" but is amazed by their sturdiness. "You can't believe how many gears, wheels, hinges, motors, and other gizmos all had to work just right," he says in his office, a futon next to him on the floor where he catches an occasional wink. Other than an overloaded computer memory that hobbled Spirit for a few weeks in the early going and was fixed by a change in procedure, showstoppers have been few.
In 1997, Squyres joined forces with Ray Arvidson, a planetary scientist at Washington University in St. Louis and onetime rival for NASA projects, to propose a Mars rover expedition. Arvidson is now his second in command of the rover science packages. Their teams of researchers, engineers, and students spent thousands of hours over several years driving practice rovers with names like FIDO (for Field Integrated Design and Operations) and K-9 across the deserts of California, Arizona, and Nevada. And while Spirit and Opportunity were en route to Mars last year, they drilled on engineering models over simulated Mars terrain at JPL. Upon landing, says Arvidson, "we had this eerie feeling we'd been there before." There is no guidebook to running robots on Mars, Squyres says, but the team is "unbelievably good at doing this now." Their skill, he says, laughing, has no other, earthly use.
For the first three months of the expedition, the 400-plus scientists and engineers split into two shifts for round-the-clock work. Arizona State University geologist Jim Rice worked both Spirit and Opportunity for all three months, catching two hours' sleep at each shift change. At 45, he has been a space nut all his life and hopes he is still fit enough in his 60s or even 70s to go to Mars himself. "We're the 21st-century Corps of Discovery," he says, invoking the Lewis and Clark expedition. The pace has slowed down somewhat, with rover workers sticking to Earth-based shifts and adjusting their tasks daily according to which rover is active.
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