NASA has stopped all work on a 鈥渓ifeboat鈥� for the International Space Station. The unpowered crew rescue vehicle (CRV) could have allowed seven astronauts to glide safely to Earth in an emergency.
Without the CRV, the crew might have to be limited to only three astronauts鈥攚ho could escape in a docked Soyuz capsule. The cut could hit the ISS science programme hard. With so few astronauts aboard, there will be precious little time for experiments in microgravity.
鈥淲e would want to avoid going down to three crew members,鈥� says Franco Bonacina, a spokesman for the European Space Agency (ESA) in Paris which is a partner in the ISS project. 鈥淲ith only three astronauts, most of their time would be devoted to maintenance.鈥�
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The CRV is based on a vehicle called the X-38 that would be permanently docked at the ISS. In an emergency, the crew would jump into the 10-metre-long craft and glide back to Earth. NASA envisaged controlling its descent with the help of the world鈥檚 largest parachute. This 700-square-metre steerable parafoil would allow the craft to land on a pair of skids.
In December 2001, a prototype X-38 released from a B-52 bomber (pictured) at an altitude of 13.7 kilometres鈥�45,000 feet鈥� landed successfully in the Californian desert. But in February, NASA scaled back spending on the ISS by about $4 billion, in a bid to keep total costs down to $25 billion. The CRV would cost about $1 billion to develop fully, with a fleet of four craft the aim.
But the three crew members now envisaged for the ISS would spend almost all of their time keeping the station running. That would allow only a few hours a week for science activities. When the cuts were first mooted in February, Congressman Nick Lampson, a Texas Democrat, said: 鈥淚 will remind everyone that the lesson we learned from the Titanic and the Challenger tragedies is that everyone gets a seat in the lifeboat.鈥�
NASA is still negotiating the issue with Congress, ESA and its other space station partners around the world. It says a final decision could be announced late this year.
Of the three options being considered, only one involves reinstating the lifeboat. Another is to require that at least two Russian Soyuz capsules are docked at the station at all times. This would allow up to six astronauts to be aboard. The third option is to provide a sturdy 鈥渟afe haven鈥� within the ISS equipped with air, food and medical supplies. Some or all of the crew could hole up there in an emergency until help arrived.