All Systems Go For Shuttle Launch

By CBSNews.com staff CBSNews.com staff

June 1, 1998 / 10:12 PM EDT / CBS

After a three-day struggle, the cosmonauts aboard Mir fixed their automatic steering system, and NASA is pressing ahead with plans to send space shuttle Discovery on one last docking flight Tuesday.

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NASA officials said Discovery was fueled Tuesday morning and that perfect weather was forecast for its scheduled takeoff shortly after 6 p.m. EDT Tuesday evening.

Mir's steering system is needed to keep the Russian space station steady when a shuttle links up with it. Before the problem was fixed Monday, NASA was debating whether to delay the shuttle launch because of the danger of a wobbly Mir.

This mission will be NASA's ninth and final shuttle hookup with Mir. Discovery will bring home Andrew Thomas, the last American astronaut to live on the aging Russian outpost.

CBS News Space Consultant William Harwood reports that Thomas is anxious to go home. "When the shuttle gets back down on the ground, he will have spent 140 days in space," Harwood says. "He talked to Russian controllers from Mir and said the first thing he was looking forward to was a homecoming meal of lasagna and Oreo cookies."

The acting director of Russia's Mir-shuttle program, Boris Sotnikov, announced the good news Monday at Kennedy Space Center. "The situation is basically under control, and there is no reason to delay," Sotnikov said.

NASA said it would continue to monitor the station's steering system and its computer, which failed over the weekend. But space agency officials stressed they were confident with the repairs.

"It's interesting that at the very end of the program, after such a smooth increment for Andy, that we had this problem occur with the motion-control system," said Frank Culbertson, director of NASA's shuttle-Mir program. "It's frustrating to a certain extent, but, hey, maybe it's our signature. It certainly adds some drama to it."

The computer that controls Mir's automatic steering system failed Saturday and was replaced by the three-man crew on Sunday, but the new computer also shut down. Engineers initially suspected bad software, but finally traced the problem to an electronics box.

The station now is maintaining its alignment using thrusters, which use precious fuel. It will take until late Monday to switch on all of Mir's 11 gyroscopes, the station's preferred, fuel-free orientation system.

"The station can stay on thrusters for quite a while, so even if there is a problem with the gyroscopes, the docking won't be jeopardized," sai Russian Mission Control spokesman Valery Lyndin.

Mir's main computer operates the station's motion control system, and when it fails, the station's energy supply dwindles since it can't rotate to keep its solar panels in full alignment with the sun.

Luckily, when the latest trouble occurred, the station was on a so-called solar orbit, which puts it in direct sunlight round the clock. As a result, Mir's batteries remained fully charged, making it easier to reactivate the steering system.

Until the computer failed over the weekend, Thomas had been enjoying a "remarkably peaceful and benign" flight. Some of his six predecessors had much bumpier Mir rides. One fought a fierce fire; another endured a near-catastrophic collision.