String of accidents could leave International Space Station without crew

A string of accidents has raised doubts about Russia's capability to resupply the International Space Station and prompted worries that the orbiting research platform – continuously inhabited for a decade – may have to be abandoned, at least temporarily.

The Russian space agency Roskosmos officially announced today that it will delay planned flights to resupply the ISS and rotate its crew until the causes of last week's crash of a Progress space freighter can be explained and corrected. Russia's Progress robot cargo ships and Soyuz manned space vehicles have been the only means of reaching and resupplying the station since the US space agency NASA retired its last space shuttle, the Atlantis, in July.

Three of the six astronauts currently aboard the ISS were scheduled to be replaced in late September by a Soyuz mission, but that has now been pushed back by at least a month.

"We expect that the next manned launch will take place in late October or early November, not earlier. That is our plan," said Roskosmos' manned spaceflight programme director, Alexei Krasnov, on Monday, according to the official RIA-Novosti agency. "If for some reason we fail to send up the next crew by the end of November, we will have to study all the available options, including one of leaving the station unmanned," he added.

Russia's resurgent space program makes heavy use of technology developed by the former USSR, including the powerful Proton-M rocket, which is used to loft both Progress and Soyuz vehicles into orbit.

But various rocket malfunctions appear to be behind at least four serious accidents in the past nine months. In addition to last week's crash of the Progress freighter, which was carrying 3 tons of food, fuel and water to the ISS, an Express AM-4 telecommunications satellite was lost in early August when it failed to separate from its Proton-M carrier rocket and had to be jettisoned. In February the launch of a military geodesic satellite ended in failure. Yet another crippling setback occurred last December, when 3 satellites crucial to finalizing Russia's ambitious Glonass orbiting navigation system crashed into the Pacific Ocean.

Russian experts point out that their technology, though old, is proven to be reliable. The Progress accident was the first of its kind in 130 missions of the robot freighters since they were introduced in 1972. The basic design of the Proton rocket hasn't changed much since one of its ancestors hurled Yury Gagarin into orbit half a century ago – aboard an original Soyuz spacecraft.

But some analysts have been warning that the industrial infrastructure that supported the once-mighty Soviet space program has long since disintegrated and serious problems of quality control may have crept in. They also suggest that tinkering with the old tried-and-true designs might have introduced new and unpredictable flaws.

No one seems to know how long it might take the Russians to discover and iron out the problems, and that means the outcome of the ISS is now hanging by a thread.

"We're focused on keeping the crew safe. Our next focus is on keeping the ISS manned," said Michael Suffredini, NASA's space station program manager, at a press conference Monday.

"But if we have to de-man the ISS, we certainly have a safe way to do that. We'll try to prevent that if we can," he added.