Columbia was the first Space Shuttle orbiter and flew 28 missions between 1981 and 2003. On its first mission in 1981, Columbia proved the concept of a reusable winged spacecraft. However, in 2003 during its 28th mission re-entry, Columbia disintegrated over Texas, killing all 7 crew members aboard. Over its 24 years of service, Columbia was the first orbiter to accomplish many milestones and spent over 300 cumulative days in space.