OPS 9311-9317 & GGTS-1

The IDCSP (Initial Defense Communications satellite Program) provided the Pentagon with its first near-geosynchronous communications system and replaced the cancelled ADVENT project.

GGTS (Gravity Gradient Test Satellite) were two experimental satellites to investigate gravity gradient stabilization in geostationary orbits. They were each launched together with 7 IDCSP communications satellites.