STS-121 was a 2006 Space Shuttle mission to the International Space Station (ISS) flown by Space Shuttle Discovery on its 32nd flight. The main purposes of the mission were to test new safety and repair techniques introduced following the Columbia disaster of February 2003 as well as to deliver supplies, equipment, and European Space Agency (ESA) astronaut Thomas Reiter to the ISS.
After two weather-related delays, the shuttle successfully launched on Tuesday, July 4, 2006, at 14:37:55 EDT. It was the first and only shuttle launch on the United States' Independence Day. The mission lasted for 13 days before landing at the Kennedy Space Center on July 17, 2006, at 09:14:43 EDT.