Tripped Breaker Interrupts Space Station Science

The Endeavour astronauts replaced an International Space Station circuit breaker that tripped Monday, bringing to a halt the flow of data from a new $2 billion cosmic ray detector and other science payloads on the outpost.

The data outage lasted about five or six hours. But U.S. astronaut Ron Garan, a flight engineer aboard the station, was able to reroute cabling to save imagery taken during an unprecedented Soyuz spacecraft departure from the outpost.

The saved imagery included views being beamed back to the station from the Soyuz spacecraft as Russian cosmonaut Dmitry Kondratyev, U.S. astronaut Catherine "Cady" Coleman and European astronaut Paolo Nespoli began a return to Earth. It was the first time a Soyuz had departed the station while a shuttle was docked at the outpost.

The Remote Power Controller Module was one of about 180 used to distribute electricity to station systems and provide over-current protection. The failed unit routed electricity to video equipment as well as the newly delivered Alpha Magnetic Spectrometer, other station payloads and gear used to transfer files between the outpost and Earth.

So data generated by the AMS and other payloads could not be downlinked to Earth until the failed box could be replaced with a spare.

The removal and replacement work was done by Endeavour mission specialist Mike Fincke. A first-time shuttle flyer, Fincke who is a veteran of two previous expeditions to the station and has spent more than a year in orbit.