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 Independence Space Center outside Houston, Texas. The replica shuttle was stripped of the name "Explorer" as part of the dismantling process. Upon arriving in the Houston area by barge on June 1, 2012, the shuttle was taken to the Johnson Space Center dock on Clear Lake, and preparations were made to move the shuttle to Space Center Houston during the early morning hours. As with Florida, several light poles along NASA Parkway were taken down and trees trimmed back to allow passage. The shuttle was moved by another 144-wheel trailer down the closed highway to the visitor center. Johnson Space Center