Sensor Failure Threatens Space Shuttle Launch

NASA officials said on Saturday they would not launch the shuttle unless all four sensors worked.

One sensor failed on Sunday as NASA fueled the space shuttle Atlantis for a trip to the International Space Station, threatening the launch attempt set for 3:21 p.m. EST (2021 GMT).

"Liquid hydrogen sensor number three has failed. This is not good news," launch commentator George Diller said just after fueling began.

NASA officials said on Saturday they would not launch the shuttle unless all four sensors worked.

Diller said technicians would continue to fuel the shuttle and make tests.

Sensor failures delayed the launch, originally scheduled for Thursday, and officials had been working on a way to launch the mission anyway.