{{short description|First flight of the second Boeing X-37B}} {{Use dmy dates|date=October 2019}} {{Infobox spaceflight | name = USA-226 | image = OTV-2_X-37B.jpg | image_caption = The X-37B back on Earth after completing OTV-2 | mission_type = Demonstration | operator = Air Force Space Command | website = | COSPAR_ID = 2011-010A<ref name="heavens-info">{{cite web |url=http://www.heavens-above.com/satinfo.aspx?satid=37375 |title=X-37B - Satellite Information |work=Heavens Above |access-date=10 July 2013}}</ref> | SATCAT = | mission_duration = 468 days, 13 hours, 2 minutes<ref name="landing"/> | spacecraft_type = Boeing X-37B | manufacturer = Boeing | dry_mass = {{convert|NNNN| | |abbr=on}} | launch_mass = {{convert|5400|kg|lb|abbr=on}}<ref name="GSP">{{cite web |url=http://space.skyrocket.de/doc_sdat/x-37.htm |title=X-37B OTV 1, 2, 3 |work=Gunter's Space Page |first=Gunter D. |last=Krebs |access-date=10 July 2013}}</ref> | power = Deployable solar array, batteries<ref name="GSP" /> | launch_date = {{Start-date|5 March 2011, 22:46:00|timezone=yes}} UTC<ref name="nssdc-launch">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2011-010A |title=OTV 2: Launch information |work=National Space Science Data Center|access-date=10 July 2013}}</ref> | launch_rocket = Atlas V 501<ref name="GSP" /> | launch_site = Cape Canaveral SLC-41 | launch_contractor = United Launch Alliance | landing_date = {{End-date|16 June 2012, 12:48:00|timezone=yes}} UTC<ref name="landing"/> | landing_site = Vandenberg, Runway 12 | orbit_epoch = 30 May 2012, 02:23:10 UTC<ref name="heavens-orbit">{{cite web |url=http://www.heavens-above.com/orbit.aspx?satid=37375 |title=X-37B - Orbit |publisher=Heavens Above |date=30 May 2012 |access-date=10 July 2013}}</ref> | orbit_reference = Geocentric | orbit_regime = Low Earth | orbit_periapsis = {{convert|278.5|km|mi|abbr=on}}<ref name="heavens-orbit" /> | orbit_apoapsis = {{convert|289.3|km|mi|abbr=on}}<ref name="heavens-orbit" /> | orbit_inclination = 41.9°<ref name="heavens-orbit" /> | orbit_semimajor = {{convert|6662|km|mi|abbr=on}}<ref name="heavens-orbit" /> | orbit_eccentricity = 0.0008<ref name="heavens-orbit" /> | orbit_period = 90.2 min<ref name="heavens-orbit" /> | orbit_mean_motion = 15.96<ref name="heavens-orbit" /> | apsis = gee | instruments = | insignia = | insignia_caption = | insignia_size = | programme = '''OTV program''' | previous_mission = OTV-1 | next_mission = OTV-3 }} '''OTV-2''' (also known as '''USA-226'''<ref name="heavens-info" />) 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."<ref>{{cite news |url=https://www.csmonitor.com/USA/Military/2010/0420/Air-Force-to-launch-X-37-space-plane-Precursor-to-war-in-orbit |title=Air Force To Launch X-37 Space Plane: Precursor To War In Orbit? |work=The Christian Science Monitor |last=Lubold |first=Gordon |date=20 April 2010 |access-date=23 April 2010}}</ref>
==Launch== 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.<ref name="Atlas">{{cite web |url=http://www.spaceflightnow.com/atlas/av026/status.html |title=Mission Status Center (OTV-2) |work=Spaceflight Now |first=Justin |last=Ray |date=5 March 2011 |access-date=10 July 2013}}</ref><ref>{{cite news |url=http://latimesblogs.latimes.com/technology/2011/03/x-37b-launch-air-force-space-plane.html |title=Air Force hopes to launch X-37B space plane after weather delay |work=Los Angeles Times |series=Technology |first=W. J. |last=Hennigan |date=5 March 2011 |access-date=5 March 2011}}</ref> 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.<ref name="GSP" />
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.<ref name="Atlas"/> It was returned to the Vertical Integration Facility the following day for final assembly.<ref name="MSC">{{cite web |url=http://www.spaceflightnow.com/atlas/av012/status.html |title=Mission Status Center (OTV-1) |work=Spaceflight Now |first=Justin |last=Ray |date=23 April 2010 |access-date=23 April 2010}}</ref>
==Mission== Most of the mission parameters for the first OTV-2 flight have not been disclosed.<ref name="sfnfeb">{{cite news |url=http://spaceflightnow.com/atlas/av012/100225x37arrival/ |title=Air Force X-37B spaceplane arrives in Florida for launch |work=Spaceflight Now |first=Stephen |last=Clark |date=25 February 2010 |access-date=3 March 2010}}</ref> 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.<ref>{{cite news |url=http://www.spaceflightnow.com/news/n1111/29otv2/ |title=Military space shuttle receives mission extension |work=Spaceflight Now |first=Stephen |last=Clark |date=29 November 2011 |access-date=10 July 2013}}</ref>
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.<ref>{{cite web |url=http://www.strategypage.com/dls/articles/X-37-Evolves-Into-A-Mini-Space-Shuttle-12-14-2011.asp |title=X-37 Evolves Into A Mini Space Shuttle |work=Strategy Page |first=James |last=Dunnigan |date=14 December 2011 |access-date=6 January 2012}}</ref>
===Altitude and ground track resonance history===
{| class="wikitable" |- ! Time period ! Periapsis<br>(AMSL) ! Apoapsis<br>(AMSL) ! Resonance<br>(orbits:days) |- | 2011 Mar 5 – 14<ref name="seesat_Mar-2011_0187">{{cite web |url=http://www.satobs.org/seesat/Mar-2011/0187.html |title=X-37B OTV 2-1 found by Greg Roberts |work=SatObs.org |first=Ted |last=Molczan |date=9 March 2011}}</ref> | {{convert|317|km|abbr=on}}<ref name="seesat_Mar-2011_0187"/> | {{convert|319|km|abbr=on}}<ref name="seesat_Mar-2011_0187"/> | |- | 2011 Mar 14 – 30<ref name="seesat_Mar-2011_0238">{{cite web |url=http://www.satobs.org/seesat/Mar-2011/0238.html |title=Updated X-37B OTV 2-1 elements |work=SatObs.org |first=Ted |last=Molczan |date=14 March 2011}}</ref> | {{convert|317|km|abbr=on}}<ref name="seesat_Mar-2011_0238"/> | {{convert|344|km|abbr=on}}<ref name="seesat_Mar-2011_0238"/> | |- | 2011 Mar 30 – 16 Jun<ref name="seesat_Mar-2011_0369">{{cite web |url=http://www.satobs.org/seesat/Mar-2011/0369.html |title=Updated X-37B OTV 2-1 elements |work=SatObs.org |first=Ted |last=Molczan |date=30 March 2011}}</ref> | {{convert|323|km|abbr=on}}<ref name="seesat_Mar-2011_0369"/> | {{convert|339|km|abbr=on}}<ref name="seesat_Mar-2011_0369"/> | |- |}
thumb|Landing video of OTV-2 at Vandenberg AFB
==Landing== 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).<ref name=landing>{{cite news |url=http://www.spaceflightnow.com/atlas/av026/landing/ |title=Air Force's mini space shuttle returns after 468-day flight |work=Spaceflight New |last=Ray |first=Justin |date=16 June 2012 |access-date=16 June 2012}}</ref> 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<ref name="rockets_and_people">{{cite book |url=https://ntrs.nasa.gov/search.jsp?R=20050010181 |title=Rockets and People |volume=1 |publisher=National Aeronautics and Space Administration |series=NASA History Series |first=Boris E. |last=Chertok |editor-first=Asif A. |editor-last=Siddiqi |year=2005 |page=179 |id=SP-2005-4110}}</ref> and the second, its sister craft, the OTV-1.<ref>{{cite news |url=http://www.spaceflightnow.com/news/n1012/03x37landing/ |title=Home again: U.S. military space plane returns to Earth |work=Spaceflight Now |first=Stephen |last=Clark |date=3 December 2010}}</ref>
==See also== {{Portal|Spaceflight}} *2011 in spaceflight *Lockheed Martin X-33 *USA-212
==References== {{reflist|30em}}
==External links== *[https://www.youtube.com/watch?v=-cvrjzoHZg4 Video of the landing of USA-226]
{{X-37B flights}} {{Orbital launches in 2011}}
Category:Spacecraft launched in 2011 Category:DARPA Category:Satellites of the United States Air Force Category:Spacecraft which reentered in 2012 Category:USA satellites Category:Articles containing video clips Category:Boeing X-37