IRIS Spinning Stage - A perigee stage for satellites up to 900 kg to be launched from the Space Shuttle with the IRIS system

The design of the IRIS Spinning Stage (ISS), the propulsion unit which with the reusable airborne support systems and the ground-support equipment comprises the IRIS GTO-injection system, is presented and illustrated with drawings. The ISS includes payload attachment and separation fittings; a thermal-control system; electronic systems (power supply, sequencer, and nutation control); telemetry (2K baud, 5-W, 2.2-2.3 GHz; with 80 analog and 48 digital channels); and an end-burning-configuration HTPB-1813 solid-fuel motor providing maximum total impulse 4.49 MN sec with burn time 79 sec and propellant weight 1574 kg. The ISS is scheduled to achieve operational status by the end of 1986.