On April 22, 2010 an Atlas 5 / 501 (AV-012) rocket was launched from Cape Canaveral at 23:52 UTC to propel into orbit the U.S. military's experimental X-37B spaceplane (Orbital Test Vehicle), the prototype for an unmanned reusable space shuttle.
It was the 603rd launch of the Atlas family rocket-carries since 1957, the 21st launch of Atlas 5 and the 1st launch of Atlas 5 in the "501” configuration.
