.jpg) Launch of OTV-4 | |
| Mission type | Classified |
|---|---|
| Operator | Air Force Space Command |
| COSPAR ID | 2015-025A |
| SATCATno. | 40651 |
| Mission duration | 1 year, 11 months and 17 days |
| Spacecraft properties | |
| Spacecraft type | Boeing X-37B |
| Manufacturer | Boeing |
| Launch mass | 5,400 kg (11,900 lb)[1] |
| Power | Deployable solar array, batteries[1] |
| Start of mission | |
| Launch date | 20 May 2015 (2015-05-20Z) |
| Rocket | Atlas V 501 |
| Launch site | Cape CanaveralSLC-41 |
| Contractor | United Launch Alliance |
| End of mission | |
| Landing date | 7 May 2017 (2017-05-08) |
| Landing site | Shuttle Landing Facility Runway 15 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Perigee altitude | 312 km (194 mi) |
| Apogee altitude | 325 km (202 mi) |
| Inclination | 43.50 degrees |
| Period | 90.93 minutes |
OTV program | |
USA-261, also referred to asOrbital Test Vehicle 4 (OTV-4) orAFSPC-5, is the second flight of the secondBoeingX-37B, an American unmannedvertical-takeoff, horizontal-landingspaceplane. It was launched tolow Earth orbit aboard anAtlas V rocket fromCape Canaveral on May 20, 2015. Its mission designation is part of theUSA series.
The spaceplane was operated by theAir Force Space Command, which considers the missionclassified and as such has not revealed the objectives. However, the Air Force did reveal that the X-37 would be carrying an experimentalhall-effect thruster for testing ahead of potential use in futureAEHF satellites.[2] Additionally,NASA announced it was flying a materials science payload similar toMISSE called METIS.[3]
OTV-4 is the second mission for the second X-37B, and the fourth X-37B mission overall. It flew on anAtlas V rocket, with a 5-meter payload fairing and nosolid rocket boosters.[4]
Originally scheduled to launch on May 6, OTV-4 was delayed until May 20 for undisclosed reasons.[3] OTV-4 launched successfully at 11:05 Eastern Time on May 20, 2015.[5]
OTV-4 stayed in orbit for a record-setting 718 days, beatingOTV-3's record of 674 days.[6] OTV-4 landed on May 7, 2017 at theShuttle Landing Facility.[6]
NASA utilized the launch of OTV-4 to fly the eleventhELaNaCubeSat rideshare mission. Ten cubesats were deployed from aP-POD deployment system affixed to theCentaur upper stage.[7]
ELaNa XI includedLightSail-1, an experimentalsolar sail.[7]