The international space station is about to get its third U.S.-Russian crew in less than one year. The new team lifted off aboard the U.S. space shuttle Discovery late Friday to relieve the current station crew, which has been in orbit for about five months.
A U.S. commander and two Russian cosmonauts are ready to replace Russian Commander Yuri Usachev and U.S. Astronauts Jim Voss and Susan Helms, who have lived on the station since early March. Crew rotations are supposed to occur every four-months, but this one is a month late. It was delayed when problems with the station's new robot arm postponed the previous shuttle visit, which required the arm for construction operations.
That mission completed a very busy year for station assembly. In 12 months, seven U.S shuttles and seven Russian rockets brought up many new components.
The head of the station program, Tommy Holloway, says they include solar energy wings, U.S. and Russian command modules, the first research laboratory, the robot arm, and a passageway through which space walkers can continue construction chores with the arm between shuttle visits. "As I reflect on these 14-flights, I find them to be some of the most complex, interactive, interdependent flights that we have ever accomplished in human space flight," he said. "I do not believe there has been a period in history when we have really done so much that was so complex and so interactive."
Now, Discovery's mission heralds a change of pace aboard the station. In contrast to the frequent shuttle visits during the past year, there will be none during the new crew's occupation as the rate of assembly slows.
According to shuttle flight director Mark Ferring, for the next four months, only a Russian docking compartment will be added when a Russian rocket carries it to the station in September. "It is astounding to me, really, what we have done in the last year," he said. "With all this flurry of activity, it is time that we restock the station and kind of take a breath for a while and that is a little bit what is happening on our mission."
The shuttle will bring 4,000 kilograms of new supplies and equipment for the new station crew.
Their mission will differ from the first two station teams. The initial residents set up the outpost for living last year. The present occupants made the transition to scientific research when the U.S. laboratory was added. But the new commander, veteran U.S. Astronaut Frank Culbertson, explains his crew will have more time for research during the next four months. "There is a lot of research on board and we will be going through, I think, a more laboratory type period where we will be conducing routine operations, hopefully, finishing the experiments, repairing them if necessary, reworking them if necessary," he said. "So I think we will see a little more shift in that direction."
Commander Culbertson's crewmates for the new expedition are Russian cosmonauts Mikhail Tyurin, a space novice, and Vladimir Dezhurov, a former commander of the Russian Mir space station.
Mr. Culbertson brings an unusual perspective to orbit. After nine years as an astronaut, he oversaw nine shuttle missions to Mir that helped prepare the U.S. space agency for joint international station activities with Russia.
Station program chief Tommy Holloway notes Mr. Culbertson then managed the outpost's operations for a year. "Frank is a unique individual in this process," he said. "Now he has come full circle and will be back in orbit and implementing all that he has learned."
Before the shuttle Discovery leaves the new station team behind, two astronauts will conduct spacewalks to install new equipment on the outpost and make repairs.