 In the late 1980s, a planned successor to STS was called "Shuttle II", which encompassed a number of different ideas and was influenced by the Challenger disaster.At one point before retirement, extension of the Space Shuttle program for an additional five years while a replacement could be developed, was considered by the U.S. government.Some programs to provide access to space after the shuttle were the Lockheed Martin X-33, VentureStar, the Orbital Space Plane Program, and Ares I launcher.