[3] At the end of its seven-year design life it was replaced by the newly launched INSAT-1D, dropping to backup status.

The spacecraft carried twelve C and three S band transponders, powered by a single solar array.

[3] A stabilisation boom was used to counterbalance radiation torques from the satellite's asymmetrical design.

Challenger lifted off from Launch Complex 39A at the Kennedy Space Center at 06:32:00 UTC on 30 August 1983.

In August 1993 it was decommissioned and raised to a graveyard orbit slightly above geosynchronous altitude.