The flight was originally scheduled to launch, on 6 December 2007. A problem with a part of the fuel tank used to work out how much fuel was left went wrong, which meant the start of the flight had to be delayed. After the same part went wrong in an attempt to start the flight on 9 December, the start of the flight was moved to January 2008, and later to February. The flight started on 7 February 2008. Some people at NASA were worried that bad weather might stop the launch, but the bad weather cleared up in time for a good launch.