When astronauts and cosmonauts close the hatches today between the space shuttle Discovery and Russia's Mir space station, they will also close a unique chapter in the history of human spaceflight.
Never before have two countries - onetime enemies with widely disparate languages and cultures - so closely intertwined their manned spaceflight programs. In the process, the United States and Russia have learned valuable lessons about different approaches to scientific endeavor that will shape both nations' quest to explore the heavens in the future.
The lessons range from the arcane to the profound. In their 31 months together aboard the insect-looking orbiter, astronauts and cosmonauts grew dwarf wheat together, shared borscht, survived several harrowing malfunctions, and gained valuable insight into how to maintain crew morale during prolonged missions in space.
(One hint: Let members "phone home" more often and with less static.)
In all, the National Aeronautics and Space Administration (NASA) has compiled a data base of 479 "lessons learned," including the mundane but important task of coordinating mission-control operations. They will undergird the launch in November and December of the first elements of the International Space Station (ISS), Earth's orbiting outpost for the 21st century.
"It's very difficult to imagine beginning assembly of the International Space Station and beginning station operations without doing what we have done during the shuttle-Mir program," says Frank Culbertson, who directed the program for NASA.
Within the past two weeks, the international partners - the US, Russia, Canada, Japan, and the European Space Agency - have agreed on the latest construction schedule for the station. And NASA has set up an office in Russia to oversee the transition from the shuttle-Mir program, the first phase of the ISS effort, to the building and operation programs.
Mr. Culbertson says the joint Mir effort met or exceeded all of its goals. Others agree. "I think it's been quite valuable," says Ray Williamson, a professor at the Space Policy Institute at George Washington University in Washington. "Our astronauts have learned more about what it's like to be in space for long periods. We could have invented it ourselves, started from scratch. But why not learn it early, so we have a better sense" of what it's like?
SINCE Norman Thagaard rode a Russian Soyuz capsule to spend 115 days aboard Mir in March 1995, US astronauts have logged 31 months on the station, working with their cosmonaut colleagues. When Shannon Lucid took up residence on Mir set in March 1996, she assumed the lead-off position in what was to become 27 months of continuous US presence on the station, ending with Andrew Thomas's return at the end of the current shuttle flight.
"The stamina of the American astronauts has been extraordinary," says James Oberg, a space consultant and aerospace engineer in Houston. "They stuck it out through conditions much harder than they thought in the beginning, and the conditions never got any better."
Indeed, through much of last year, Mir seemed to lurch from one crisis to another. In February, with Jerry Linenger aboard, a fire broke out. Then, during Michael Foale's stint between May and September, a Russian resupply capsule glanced off the space station's "Spekter" module. The collision punctured the module and damaged a solar panel, forcing the crew to seal part of the station and severely restrict power. Chronic problems with computers and cooling systems have also dogged the station.
To NASA officials, these problems became invaluable in learning the art of crisis management in space - something both countries will need in running the international station. "One of the main things the Phase 1 program has given us is the ability to work on problems together," he says.
Yet as the troubles mounted, so did questions about whether the station was safe enough to merit continuing the $478-million program. "NASA learned everything it needed to learn in the first three or four flights," says Rep. F. James Sensenbrenner Jr. (R) of Wisconsin, chairman of the House Science Committee. "We should have pulled the plug when Mir started falling apart."
Indeed, Mr. Oberg maintains that working out crisis-management procedures on the fly is no way to run a space program. "If you wait for a flight to learn that, you are irresponsible," he says. "By bragging about how they learned this in flight, they are really underscoring their inadequate preparations."
Yet staying the course despite the troubles on Mir could have long-term benefits, others say. "It showed that the complexity of a space station is much more than had been anticipated," says Charles Kauffman, an engineering professor at the University of Michigan in Ann Arbor. "I think we were rather naive concerning that."