The Space Shuttle Enterprise was the first shuttle built for NASA's Space Shuttle program. It was designed for testing and did not have engines or heat shields for space travel. Instead, it was used for a series of approach and landing tests to evaluate the shuttle's performance during re-entry and landing. Enterprise was unveiled in 1976 and conducted its first free flight in 1977. It was named after the fictional starship from the Star Trek television series, following a campaign by fans. Although it never flew in space, Enterprise played a crucial role in the development of later shuttles like Columbia and Challenger.