NASA has called off this afternoon's launch of space shuttle Atlantis, citing a glitch involving fuel tank sensors, Space.com reports. “We’ll try it again tomorrow,” said a NASA spokesman. Two of four sensors in the shuttle's liquid hydrogen tank were registering empty, even though the tanks were full, reports the Orlando Sentinel. At least three must be working in order for NASA to OK a launch.
The sensors are a backup system, in any case, the Sentinel reports. A computer usually shuts off the shuttle's engines at a set time, but in case of computer failure the sensors tell the shuttle to kill the engine when it runs out of fuel. The shuttle's mission is to deliver the European-built Columbus laboratory to the Space Station.