Astronauts may need to take the unprecedented step of temporarily abandoning the International Space Station after a Russian rocket launch accident last week.
Until officials figure out what went wrong with Russia’s essential Soyuz rockets, there will be no way to launch any more astronauts before the current residents have to leave in mid-November.
The unsettling predicament comes just weeks after NASA’s final space shuttle flight.
“We have plenty of options,” said NASA’s space station program manager, Mike Suffredini.
“We’ll focus on crew safety as we always do.”
Abandoning the space station, even for a short period, would be an unpleasant last resort for the world’s five space agencies that have spent decades working on the project. Astronauts have been living aboard the space station since 2000, and the goal is to keep it going until 2020.
Mr Suffredini said flight controllers could keep a deserted space station operating indefinitely, as long as all major systems were working properly. The risk to the station goes up, however, if no one is on board to fix equipment breakdowns.
Six astronauts from three countries presently are living on the orbiting complex. Three are due to leave next month — the other three are supposed to check out in mid-November.
The September 22 launch of the next crew — the first to fly in this post-shuttle era — has already been delayed indefinitely. Russia’s Soyuz rockets have been the sole means of getting full-time station residents up and down for two years.
To keep the orbiting outpost with a full staff of six for as long as possible, the one American and two Russians due to return to Earth on September 8 will remain on board at least an extra week.
As for supplies, the space station is well stocked and could go until next summer, Mr Suffredini said. Atlantis dropped off a year’s supply of goods just last month on the final space shuttle voyage.
The unmanned Soyuz craft destroyed last week was carrying 3 tonnes of supplies.
For now, operations are normal in orbit, Mr Suffredini said, and the additional week on board for half the crew will mean additional science research.
The Soyuz has been extremely reliable over the decades — this was the first failure in 44 Russian supply hauls for the space station. Even with such a good track record, many in and outside NASA were concerned about retiring the space shuttles before a replacement was ready to fly astronauts.
Russian space officials have set up an investigation team and until it comes up with a cause for the accident and a repair plan, the launch and landing schedules remain in question.
None of the spacecraft debris has been recovered yet — the wreckage fell into a remote, wooded section of Siberia. The third stage malfunctioned — a sudden loss of pressure apparently was noted between the engine and turbopump.
While a crew may well have survived such an accident because of safety precautions built into the manned version of the rocket, no one wants to take any chances.
One or two unmanned Soyuz launches are on tap for October, one commercial and the other another space station supply run. Those would serve as important test flights before putting humans on board, Mr Suffredini said.
NASA considered vacating the space station before, following the space shuttle Columbia disaster in 2003. Back then, shuttles were still being used to ferry some station residents back and forth. Instead, the station got by with two-man crews for three years because of the significant cutback in supplies.
The space station’s population doubled in 2009, to six. It wasn’t until the space station was completed this year that science research finally took priority.
Even if the space shuttles were still flying, space station crews would need Soyuz-launched capsules to serve as lifeboats, Mr Suffredini said.
The capsules are certified for no more than six and a half months in space, thus the need to regularly rotate crews. Complicating matters is the need to land the capsules during daylight hours in Kazakhstan, resulting in weeks of blackout periods.
NASA wants US private companies to take over crew hauls, but that’s three to five years away at best. Until then, Soyuz capsules are the only means of transporting astronauts to the space station.