A major power shortage at the International Space Station has delayed this week's SpaceX supply run. SpaceX was supposed to launch a shipment Wednesday, the AP reports. But an old power-switching unit malfunctioned at the space station Monday and knocked two power channels offline. The six remaining power channels are working normally, according to NASA. NASA stressed Tuesday that the station and its six astronauts are safe, but because of the hobbled solar-power grid, the SpaceX launch is off until at least Friday. NASA wants to replace the failed unit to restore full power before sending up the SpaceX Dragon cargo capsule.
The breakdown has left the station's big robot arm outside with one functioning power channel instead of two. Two power sources are required—one as a backup—when the robot arm is used to capture visiting spacecraft like the Dragon. Flight controllers will use the robot arm to replace the bad unit with a spare later this week, saving the astronauts from going out on a spacewalk. Solar wings collect and generate electricity for the entire space station, and any breakdown in this critical system can cut into power and affect operations. But there's no rush for this delivery: Northrop Grumman launched supplies two weeks ago. SpaceX, meanwhile, is still investigating last month's fiery loss of its new Dragon capsule designed for astronauts.
(Read more International Space Station