Mission typeCommunications
OperatorSES Americom (2008–2009)
SES World Skies (2009–2011)
SES S.A. (2011-present)
COSPAR ID2008-038B Edit this at Wikidata
SATCAT no.33275
Mission duration15 years (planned)
14 years, 1 month, 4 days (elapsed)
Spacecraft properties
ManufacturerThales Alenia Space (prime)
Orbital Sciences (bus)
Launch mass2,473 kg (5,452 lb)
Dry mass1,161 kg (2,560 lb)
Power4.4 kW
Start of mission
Launch date14 August 2008, 20:44 UTC
RocketAriane 5 ECA
Launch siteCentre Spatial Guyanais, ELA-3
Entered serviceSeptember 2008
Orbital parameters
Reference systemGeocentric orbit
RegimeGeostationary orbit
Longitude125° West [2]
Band24 Ku-band
Bandwidth36 MHz
Coverage areaCanada, United States, Mexico, Caribbean, Central America
← AMC-18
AMC-23 →

AMC-21, or GE-21, is an American communications satellite operated by SES S.A., formerly SES World Skies and SES Americom. It was launched in August 2008 and is expected to remain in service for approximately 15 years. It is currently located at 125° West longitude.

Spacecraft and mission design

AMC-21 is based on a STAR-2 satellite bus that provides 4.4 kilowatts of power for the communications payload. The platform will support a 15-year on-orbit mission life.[3] It carries 24 Ku-band transponders at 36 MHz, which will be used to broadcast television signals to Canada, United States, Mexico, the Caribbean, and Central America.[2]


Thales Alenia Space was the prime contractor for AMC-21, and provided the satellite's communications payload. The STAR-2 bus was subcontracted to Orbital Sciences Corporation, as were integration and testing of the satellite.[3] As prime contractor, Thales Alenia Space delivered the completed satellite to SES Americom.[4]


AMC-21 was launched, along with the Superbird-7 satellite, by an Ariane 5 ECA launch vehicle on 14 August 2008 at 20:44 UTC.[5] The satellite separated from the launch vehicle in a geosynchronous transfer orbit (GTO). An onboard IHI-500 N (IHI-BT4) engine then raised it to an operational geostationary orbit and placed it at a longitude of 125° West of the Greenwich Meridian.[1] After successful completion of in-orbit testing, SES Americom took operational control of AMC-21 in September 2008.[6]

Mergers and acquisitions

In September 2009, SES Americom merged with SES New Skies to form SES World Skies, to which all of its operational satellites, including AMC-21, were transferred.


  1. ^ a b "AMC-21". Gunter's Space Page. 11 December 2017. Retrieved 5 April 2021.
  2. ^ a b "AMC-21". SES. Retrieved 5 April 2021.
  3. ^ a b "AMC-21". Orbital Sciences Corporation.
  4. ^ "Orbital-Built AMC-21 Communications Satellite Successfully Launched". Northrop Grumman. 18 August 2008. Retrieved 5 April 2021.
  5. ^ "Another successful Arianespace launch: Superbird-7 and AMC-21 in orbit" (Press release). Arianespace. 14 August 2008. Archived from the original on 18 September 2010.
  6. ^ "Orbital Reports Third Quarter 2008 Financial Results" (Press release). Orbital. 16 October 2008.