TerreStar-2, a ground spare for Reston, Va.-based TerreStar Networks’ next-generation satellite-terrestrial telephone service, is in final payload integration at Space Systems/Loral in Palo Alto, Calif.

The satellite is identical to TerreStar-1, which was launched in July 2009 aboard an Ariane 5 rocket and includes an 18-meter diameter antenna reflector enabling communication to conventionally sized mobile smartphones and other devices. When TerreStar-2 is completed, it will be stored at Space Systems/Loral’s spacecraft manufacturing and test facility until needed, Space Systems/Loral spokeswoman Wendy Lewis said April 21.