Space Shuttle gliding and landing; it was originally intended to be outfitted for orbital operations after the test program, but it was found more economical to upgrade the structural test article STA-099 into orbiter "Challenger" (OV-099). An additional test article, dubbed "Pathfinder" (OV-098), was built for form and fit tests, and is on display at the Alabama Space and Rocket Center in Huntsville, AL. "Challenger" disintegrated 73 seconds after launch in 1986, and "Endeavour" was built as a replacement from structural spare components. Building "Endeavour" cost about US$1.7 billion. "Columbia" broke apart over Texas during re-entry in 2003. A Space Shuttle launch
Space Shuttle program shuttle design that best balanced capability, development cost and operating cost. Ultimately chosen was a design using a reusable winged orbiter, reusable solid rocket boosters, and an expendable external fuel tank for the orbiter's main engines. The shuttle program was formally launched on January 5, 1972, when President Nixon announced that NASA would proceed with the development of a reusable space shuttle system. The stated goals of "transforming the space frontier...into familiar territory, easily accessible for human endeavor" was to be achieved by launching as many as 50 missions per year, with hopes of driving down per-mission costs. The prime