Monday morning, NASA announced it will postpone the planned blast off on April 19 because of a conflict with a Russian launch.
An unmanned Russian cargo ship will blast off at the end of April. NASA did not want the craft docking at the International Space Station while Endeavour was still there. The U.S. launch has now been rescheduled to April 29.
Endeavour's final flight will include astronaut Mark Kelly, husband of wounded Congresswoman Gabrielle Giffords. It will be Endeavour's final flight and the next-to-last shuttle mission.
The Associated Press contributed to this story