NASA warned Monday that the International Space Station may have to be abandoned at least temporarily later this year, following the launch failure of an unmanned Russian rocket that is also used in part to send astronauts to the outpost.
The accident last week will almost certainly force the cancellation of a scheduled Sept. 21 launch of the Russian Soyuz capsule that was part of a routine crew rotation, said Michael Suffredini, NASA space station chief and chairman of the Space Station Control Board, an international body that runs the program.
Suffredini said the agency and its partners would avoid leaving the station unmanned, if they can. “We will focus on keeping the crews safe,” he said.
When NASA retired the U.S. space shuttle system in June, it left the space station partners dependent on Russia for transporting astronauts aboard the decades-old Soyuz craft.
At the time, Suffredini expressed confidence in the Soyuz, and said NASA did not have a contingency plan in place in case the Russians ran into problems.
But Suffredini said that unless the Russians can quickly determine the cause of the rocket failure and implement a remedy, the six-member crew now on board will have to leave over the next three months.
Two Soyuz capsules are docked at the station, each with space to carry three astronauts, so there is no immediate danger to the six crew members.
NASA can operate the station from the ground without a crew, but the risks of such unmanned operations increase by tenfold the probability of a catastrophic loss of the space station. The orbiting laboratory is considered the most expensive machine ever built with a price tag of more than $100 billion.
Three of the astronauts are scheduled to return in September, but daylight conditions at the landing site in Kazakhstan would allow for only a short extension. The other three astronauts would have to return in mid-November.
The Soyuz capsule is certified to operate for 200 days, and that time limit will expire in mid-November for the last three-member crew.
The launch failure occurred last week when a Progress rocket, carrying 2.9 tons of food, fuel and supplies, experienced an engine failure, Suffredini said.
The Progress crashed in a sparsely inhabited forest in Siberia, and Russian teams have not yet located the wreckage, he said.