Mission typeClassified
OperatorU.S. Space Force
COSPAR ID2020-029A
SATCAT no.45606
Mission duration1 year, 5 months and 1 day
Spacecraft properties
Spacecraft typeBoeing X-37B
Launch mass5,400 kg (11,900 lb)[1]
PowerDeployable solar array, batteries[1]
Start of mission
Launch date17 May 2020 (2020-05-17Z)
RocketAtlas V
Launch siteSLC-41
ContractorUnited Launch Alliance
End of mission
Landing siteShuttle Landing Facility
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Perigee altitude388 km (241 mi)
Apogee altitude404 km (251 mi)
Inclination44.6 degrees

USA-299, also referred to as Orbital Test Vehicle 6 (OTV-6), is the third flight of the first Boeing X-37B, an American unmanned vertical-takeoff, horizontal-landing spaceplane. It was launched to low Earth orbit aboard an Atlas V rocket from SLC-41 on May 17, 2020 and remains in orbit. Its mission designation is part of the USA series.

The spaceplane is operated by the United States Space Force, which considers the mission classified and as such has not revealed the objectives. However an unclassified secondary satellite, FalconSat-8, was deployed from the X-37B soon after launch.[2]


OTV-6 is the third mission for the first X-37B built, and the sixth X-37B mission overall. It flew on an Atlas V in the 501 configuration, and launched from Cape Canaveral Space Launch Complex 41.[3]

OTV-6 was deployed into an orbit with an inclination of approximately 44.6°.[4]

OTV-6 remains in orbit as of May 2021.


A rideshare payload for the United States Air Force Academy, FalconSat-8, was deployed from the X-37B a few days into the mission. The satellite provides a platform for the Academy's Cadet Space Operations Squadron to test various technologies.

Onboard experiments include:

  • MEP (Magnetic gradient Electrostatic Plasma thruster), a novel electromagnetic propulsion system
  • MMA (MetaMaterials Antenna), a low power, high performance antenna
  • CANOE (CArbon NanOtubes Experiment)
  • ACES (Attitude Control and Energy Storage), a commercial reaction wheel modified into a flywheel
  • SkyPad, off-the-shelf cameras and GPUs integrated into a low power package

See also


  1. ^ a b Krebs, Gunter D. "X-37B OTV 1, 2, 3". Gunter's Space Page. Retrieved 10 July 2013.
  2. ^ "FalconSat 8". Gunter's Space Page. Retrieved 18 September 2020.
  3. ^ Graham, William (16 May 2020). "ULA Atlas V launches sixth mission for X-37B spaceplane". Retrieved 18 September 2020.
  4. ^ "OTV-6 Launch". Retrieved 18 September 2020.