Engineers resolve station-to-cargo module power problem

Editor's note...
  • Posted at 11:31 PM EDT, 03/30/12: Engineers troubleshoot station-to-cargo module power glitch
  • Updated at 01:45 PM EDT, 03/31/12: Backup power channel successfully activated
CBS News

Flight controllers and the crew of the International Space Station successfully activated a backup channel in a Russian electrical relay system Saturday, routing lab power to a European Space Agency cargo ship after an initial failure that raised the prospect of a premature undocking. With station power now flowing to the Automated Transfer Vehicle, the lab crew was told to stand down from hurried work to unload the cargo ship and to press ahead instead with plans to boost the station's altitude Saturday afternoon using the ATV's thrusters.

The European Space Agency's third Automated Transfer Vehicle, or ATV-3, approaches the International Space Station Wednesday. (Credit: NASA)
ESA's third ATV docked with the station Wednesday, gliding to a smooth linkup with the Zvezda command module's aft port. But during routine post-docking work to filter the spacecraft's atmosphere, the primary channel of a Russian equipment control system failed, interrupting the flow of station power to the cargo ship. It was not immediately known whether the problem was the result of scrubber operation or a coincidental malfunction in another system.

But the timing was unfortunate. While the ATV is equipped with four solar panels, the angle between the space station's orbit and the sun will reach a point early next week where the arrays alone will be unable to generate the necessary power. At least one RECS channel must be available to deliver station power to the cargo ship, or the crew would have no choice but to cast it off before power levels dropped too low.

Protecting their options in case the backup RECS channel did not work, flight controllers developed an expedited unloading timeline for the crew to move high priority items from the ATV to the station before time ran out. As it turned out, the work wasn't necessary. The second RECS power channel was successfully activated Saturday, restoring station power to the cargo ship.

It is still not clear what caused the primary channel to fail and as it now stands, there is no redundancy to protect against another RECS failure. But in the near term, the ATV is safely powered and if all goes well, the spacecraft will remain in place until early September as originally planned.