EchoStar T1

TerreStar-1 is an American communications satellite which was operated by TerreStar Corporation. It was constructed by Space Systems/Loral, based on the LS-1300S bus, and carries E/F band (IEEE S band) transponders which will be used to provide mobile communications to North America. The signals are transmitted by an reflector on the satellite. It had a launch mass of , making it the second most massive single satellite launched into a geosynchronous transfer orbit, and the second largest commercial communications satellite ever built. Its record as the most massive communication satellite was surpassed by Telstar 19V launched on Falcon 9 on July 21, 2018, with a mass of .

TerreStar was launched at 17:52 GMT on July 1, 2009, during a two-hour launch window that opened at 16:13. The launch occurred towards the end of the window due to bad weather in the first hour, followed by two aborted countdowns for launch attempts scheduled at 17:12 and 17:34. The launch was conducted by Arianespace, and used an Ariane 5ECA carrier rocket, flying from ELA-3 at the Guiana Space Centre. After launch, the satellite separated from the carrier rocket into a geosynchronous transfer orbit. It will subsequently raise itself into geostationary orbit by means of its onboard propulsion system. It will be positioned at 111° West longitude, and is expected to operate for 15 years. A second satellite, TerreStar-2 (now EchoStar XXI), was launched on 2017, positioned at 10E, and owned by Echostar.