August 31, 2011
Soyuz Failure May Force Crew To Abandon Space Station
Astronauts may be forced to abandon the International Space Station (ISS) in November if last week´s engine failure of a Russian Soyuz rocket is not diagnosed and fixed, a senior NASA official said on Monday.
Evacuation is a distinct possibility in mid-November if the rockets are still grounded at that time, the NASA official said.
“We´re going to do what´s the safest for the crew and for the space station, which is a very big investment of our governments,” said Michael Suffredini, NASA´s manager of the space station program, during a news briefing on Monday.
“Our job is, as stewards of the government, to protect that investment, and that´s exactly what we´re going to do.”
The $100 billion ISS has been continuously occupied since the first expedition crew opened the outpost in November 2000. Three Russian astronauts, two Americans and a Japanese are currently living there.
Last Wednesday, an unmanned Russian cargo ship named Progress, which was carrying three tons of supplies to the ISS, crashed in Siberia. Based on telemetry from the rocket, scientists believe a drop in fuel pressure led its computer to prematurely shut down the third-stage engine about five and a half minutes into flight.
The Soyuz rocket that lifts the Progress is similar to the Soyuz rocket that transports astronauts to the space station, and officials want to ensure they understand precisely what failed on last week´s launching so they can be confident it will not occur again.
Two unmanned launchings of Soyuz rockets will likely take place before the next set of three astronauts travel to the space station on September 21.
Although the loss of the Progress is of little immediate impact, one of the Russian astronauts is short on clothing and may have to borrow some from NASA, Mr. Suffredini said.
The current crew has plenty of supplies, and could remain in space longer, but what expires is their return trip home.
Two Soyuz capsules, each with seats for three passengers, are currently docked to the ISS. However, they are only certified to last 200 days in orbit due to degradation over time of hydrogen peroxide used by the craft´s thrusters.
The return of the first Soyuz capsule has been pushed back a week, to September 15, giving NASA and the Russian space agency more time to evaluate their options.
Delaying much longer than that would bump into a safety rule that mandates the capsules land during the day. The next opportunity would be in late October, which is beyond the 200-day limit.
The Russians could analyze whether the capsule´s condition could allow a longer stay, but Mr. Suffredini questioned such an approach.
“When you´ve already been handed one significant challenge, maybe you shouldn´t put another one on top of it until you sort that one out,” he said.
The other three crewmembers would return in the second Soyuz capsule in mid-November.
That would mean the space station would be empty if the problem with the Soyuz rocket had not been resolved by then.
Some experiments onboard the ISS, such as the Alpha Magnetic Spectrometer, a particle physics experiment installed in May, would continue without human management. However, other work would be suspended until the full crew of six returned to the ISS.
While all of the day-to-day ISS operations can be managed remotely, mission controllers may not be able to handle emergencies that might endanger the space station.
“There is a greater risk of losing the I.S.S. when it´s unmanned than if it were manned,” Mr. Suffredini said.
“The risk increase is not insignificant.”
With the retirement of NASA´s shuttles, the Soyuz rockets, which date back to the 1960s, will be the only way for astronauts to travel to the ISS for years to come.
Fortunately, the station can be operated indefinitely, even if unoccupied, by controllers on the ground, and would not be in immediate danger of falling out of orbit.
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