BioEd Online

The loss of a Russian supply capsule yesterday has temporarily left mission planners with no way of relieving the six-person crew aboard the International Space Station (ISS). The crew are in no immediate danger, but the situation leaves the station's long delayed ressearch programme vulnerable.

The Progress 44 capsule failed to reach orbit after its 24 August lift-off from the Baikonur Cosmodrome in Kazakhstan. The launch vehicle, a Soyuz-U rocket, was lost when its third stage failed around 5 minutes after liftoff.

The failure will likely have to be investigated before the next Soyuz launch, currently scheduled for late September. Jonathan McDowell, an astrophysicist at Harvard University in Cambridge, Massachusetts, speculates that the issue resulted either from an engine problem in the third stage or a failure of the stage to properly separate.

Either way, McDowell says, quality-control problems are evident in the Russian space programme. Earlier this month, a Russian telecommunications satellite aboard a Proton rocket was delivered to the wrong orbit. McDowell adds that the Proton and Soyuz systems are built by different companies using different technologies, so the failures are probably unrelated.

Flying solo

The station and crew are well-supplied for the time being. Japan and Europe both operate cargo vehicles, and the first private supply shipment, by US firm Space-X based in Hawthorne, California, is scheduled for November.

The full ramifications for the ISS crew are not yet clear. Three members were scheduled to return to Earth on 8 September using a capsule now docked at the station, but their mission, originally 157 days, might now be extended by another 40 or 50 days, NASA managers say. If the Soyuz problem drags on much past the end of this year, the station's remaining three crewmembers will also return to Earth, leaving the unmanned station to be controlled from the ground.

But all that is unlikely, McDowell says. The Soyuz class of rockets has completed well over a thousand launches. "It's clearly not a fundamental design issue," he says. Moreover, the Russians' familiarity with the system means that "they won't utterly panic" in the wake of the failure. "They will launch again fairly soon I would think."

Trouble ahead, trouble behind

The loss of the Soyuz vehicle is one of many setbacks to the ISS programme, which include the loss of the space shuttle Columbia and its entire crew in 2003. When the ISS crew reached its full complement of six in late-2009, NASA had hoped that the expanded crew, together with additional lab space, would allow the station to reach its potential as a science platform. In its last-ever mission on 21 July this year, the space shuttle Atlantis delivered the programme's flagship research tool, the Alpha Magnetic Spectrometer, a US$2 billion instrument designed to study antimatter in the galaxy.

News of the 24 August failure came as technicians at NASA's Kennedy Space Center in Florida were dismantling Atlantis. The loss "does bring home the implications of retiring the shuttle," McDowell says.