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 of Defense's assistance and refused the request for the spacewalk, and thus the feasibility of scenarios for astronaut repair or rescue by "Atlantis" were not considered by NASA management at the time. NASA retired the Space Shuttle in 2011, after 30 years of service. The Shuttle was originally conceived of and presented to the public as a "Space Truck", which would, among other things, be used to build a United States space station in low earth orbit in the early 1990s. When the U.S. space station evolved into the International Space Station project, which suffered from long delays and design