X-37B OTV-2 during encapsulation prior to launch
|Operator||U.S. Air Force|
|Major contractors||Boeing (spacecraft)
United Launch Alliance (LSP)
|Launch date||5 March 2011|
|Carrier rocket||Atlas V 501|
|Launch site||Cape Canaveral LC-41|
|Mission duration||468d 13h 2m|
|Landing||16 June 2012|
|Landing site||Runway 12, VAFB|
|Apoapsis||319 km (198 mi)|
|Periapsis||317 km (197 mi)|
USA-226 is the first flight of the second Boeing X-37B, the Orbital Test Vehicle 2 (X-37B OTV-2), 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 mission designation is part of the USA series.
The spaceplane was operated by the United States Air Force, 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."
OTV-2 was launched aboard an Atlas V rocket, tail number AV-026, on 5 March 2011 from Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida. It was scheduled to launch on the previous day, 4 March, but weather prevented the launch on that day, forcing the reschedule to 5 March.
The launch was conducted by United Launch Alliance.
The X-37B spacecraft was originally intended to be deployed from the payload bay of a NASA Space Shuttle, but following the Columbia accident, it was transferred to a Delta II 7920, then subsequently transferred to the Atlas V following concerns over the X-37B's aerodynamic properties during launch.
Prior to the installation of the spacecraft, the Atlas rocket was moved to the launch pad and performed a wet dress rehearsal on 4 February 2011. It was returned to the Vertical Integration Facility the following day for final assembly.
Most of the mission parameters for the first OTV-2 flight have not been disclosed. The Air Force stated the mission time would depend on progress of the craft's experiments during orbit. On 29 November 2011 a spokesperson for the Secretary of the Air Force announced the mission was extended beyond its original life expectancy, citing ongoing experimentation.
In addition to its unspecified payload, OTV-2 carried a folded solar panel in its cargo bay to power the spacecraft during its year and a half long mission.
Altitude and ground track resonance history 
|2011 Mar 5 – 14||317 km (197 mi)||319 km (198 mi)|
|2011 Mar 14 – 30||317 km (197 mi)||344 km (214 mi)|
|2011 Mar 30 – ||323 km (201 mi)||339 km (211 mi)|
After completing its mission, OTV-2 deorbited, entered the atmosphere, and landed at Vandenberg Air Force Base on 16 June 2012 at 05:48 PT (12:48 GMT). OTV-2 is the third reusable spaceplane to perform an automated landing after returning from orbit, the first being the Soviet Buran spacecraft in 1988 and the second, its sister craft, the OTV-1.
See also 
- Krebs, Gunter. "X-37B". Gunter's Space Page. Retrieved 5 August 2008.
- Ray, Justin (16 June 2012). "Air Force's mini space shuttle returns after 468-day flight". Spaceflightnow. Retrieved 16 June 2012.
- Molczan, Ted (9 March 2011). "X-37B OTV 2-1 found by Greg Roberts". http://www.satobs.org/seesat.
- Lubold, Gordon (20 April 2010). "Air Force To Launch X-37 Space Plane: Precursor To War In Orbit?". Christian Science Monitor. Retrieved 23 April 2010.
- Atlas Launch Report
- LA Times (retrieved 5 March 2011)
- Ray, Justin (23 April 2010). "Mission Status Center". Atlas Launch Report. Spaceflight Now. Retrieved 23 April 2010.
- Clark, Stephen. "Air Force X-37B spaceplane arrives in Florida for launch". Spaceflight Now, 25 February 2010. Retrieved 3 March 2010.
- James Dunnigan (14 December 2011). "X-37 Evolves Into A Mini Space Shuttle". strategypage.com. Retrieved 6 January 2012.
- Molczan, Ted (14 March 2011). "Updated X-37B OTV 2-1 elements". http://www.satobs.org/seesat.
- Molczan, Ted (30 March 2011). "Updated X-37B OTV 2-1 elements". http://www.satobs.org/seesat.
- Chertok, Boris (2005). In Asif A. Siddiqi. Raketi i lyudi [Rockets and People] (PDF). NASA History Series. p. 179. Retrieved 3 July 2006. (Russian)
- Clark, Stephen. "Home again: U.S. military space plane returns to Earth". Spaceflight Now, 3 December 2010.