Official name ECHOSTAR 21
Alternative name Echostar 21
Cospar ID 2017-032A
Norad ID 42749
Launch date 2017-06-08
Launch site TTMTR
Launch vehicle Proton-M Briz-M (Ph.3)
Country/Organization USA
Type application Communication (MSS)
Operator TerreStar Networks Inc. → Dish Network Corporation (EchoStar)
RCS size LARGE
Decay date ON ORBIT
Period (min) 1436.12
Inclination (deg) 2.02
Perigee (km) 35777
Apogee (km) 35797
Eccentricity 0.000279431078324531
Mean motion (revs. per day) 1.00270172408991
Semi-Major axis (km) 42165.135
Raan (deg) 332.6722
Arg of perigee (deg) 75.6293
Shape Box + 2 Pan + 1 Dish
Mass (kg) 6871
Height (m) 7.6
Width (m) 2.8
Depth (m) 2.8
Span (m^2) 32.4
Lifetime 15 years
Contractors Space Systems/Loral (SS/L)
Equipment S-band transponders
Propulsion ?
Configuration SSL-1300S
Power 2 deployable solar arrays, batteries

Space Systems/Loral (SS/L) announced in April 2005 completed design reviews of TerreStar Networks, Inc.'s geostationary satellite, TerreStar-1, and entered into the construction phase of the Mobile Satellite Services (MSS) program. The TerreStar satellite, together with an Ancillary Terrestrial Component (ATC), is designed to provide next-generation, 2 GHz mobile voice and data communications, monitoring and messaging services throughout the United States.

Scheduled for delivery in 2007, TerreStar-1 has a service life of 15 years and will carry a state-of-the-art MSS payload featuring a large unfurlable reflector. The satellite will be capable of generating hundreds of spot beams covering the Continental U.S., Canada, Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands. SS/L's contract with TerreStar also includes an option for construction of a second satellite, TerreStar-2.

An FCC decision earlier this year opened the door for TerreStar Networks, and other select satellite operators, to incorporate an ATC with its satellite-delivered communications service. The previously unavailable 2 GHz frequency band will allow MSS operators to provide advanced mobile voice and data services. These services will be enhanced by ATC technology, which allows for coverage in areas where a satellite's signal could be blocked, including urban canyons, dense forest or other areas out of the satellite's line-of-sight.

TerreStar-1 is based on SS/L's space-proven SSL-1300 platform, which has an excellent record of reliable operation. Its high efficiency solar arrays and lightweight batteries are designed to provide uninterrupted electrical power.

In August 2006, TerreStar contracted SSL to deliver the slightly improved second satellite Terrestar-2 in 2009. It was put into storage and is to be launched as EchoStar 21 in January 2017

Dish Network Corporation (EchoStar) acquired substantially all of the assets of TerreStar Networks in March 2012.

Satellite COSPAR Date LS Launch Vehicle Remarks
TERRESTAR 1 2009-035A 2009-07-01 FRGUI Ariane-5ECA
ECHOSTAR 21 2017-032A 2017-06-08 TTMTR Proton-M Briz-M (Ph.3)