OTV-2 (also known as USA-226) was the first flight of the second Boeing X-37B, an American unmanned robotic vertical-takeoff, horizontal-landing spaceplane. It was launched aboard an Atlas V rocket from Cape Canaveral on 5 March 2011, and landed at Vandenberg Air Force Base on 16 June 2012. It operated in low Earth orbit. Its USA-226 mission designation is part of the USA series.

The spaceplane was operated by Air Force Space Command, which has not revealed the specific identity of the payload for the first flight. The Air Force stated only that the spacecraft would "demonstrate various experiments and allow satellite sensors, subsystems, components, and associated technology to be transported into space and back."

STS-1 (Space Transportation System-1) was the first orbital spaceflight of NASA's Space Shuttle program. The first orbiter, Columbia, launched on April 12, 1981, and returned on April 14, 1981, 54.5 hours later, having orbited the Earth 37 times. Columbia carried a crew of two—commander John W. Young and pilot Robert L. Crippen. It was the first American crewed space flight since the Apollo–Soyuz Test Project (ASTP) in 1975. STS-1 was also the maiden test flight of a new American spacecraft to carry a crew, though it was preceded by atmospheric testing (ALT) of the orbiter and ground testing of the Space Shuttle system.

The launch occurred on the 20th anniversary of Vostok 1, the first human spaceflight, performed by Yuri Gagarin for the USSR. This was a coincidence rather than a celebration of the anniversary; a technical problem had prevented STS-1 from launching two days earlier, as was planned.