Canceled Space Shuttle missions

During the Space Shuttle program, several missions were canceled. Many were canceled as a result of the Challenger and the Columbia disasters. Many early missions were canceled due to delays in the development of the shuttle. Others were canceled because of changes in payload and missions requirements.

Canceled due to the late development of the shuttle

In 1972, NASA's planners had projected for 570 shuttle missions between 1980 and 1991. Later, this estimate was lowered to 487 launches between 1980 and 1992. The details of the first 23 projected missions, listed in the third edition of Manned Spaceflight (Reginald Turnill, 1978) and the first edition of the STS Flight Assignment Baseline, an internal NASA document published in October 1977, are presented below.

STS-1A (Columbia)

Originally scheduled as the first orbital test (OFT-1) for launch in June 1979. The crew was to consist of a commander and pilot, and the test flight was to last 2 days and 5 hours. No crew was named at the initial announcement of the mission, but John Young and Robert Crippen were officially announced as the STS-1 crew in March 1978, when the shuttle was still originally scheduled for a 1979 launch.