NASA Standard Spacecraft Computer-I
The NASA Standard Spacecraft Computer-I (NSSC-I) was developed at Goddard Space Flight Center in Greenbelt, Maryland, as a standard component for Earth Orbiting Missions.
The precursor of the NSSC-I was the Advanced Onboard Processor (AOP) built by Grumman Corporation for the Orbiting Astronomical Observatory (OAO) mission.
The NSSC-I was used on the IUE, SMM, Space Telescope, and Landsat program. It became part of the MultMission Modular Spacecraft (MMS).
It was an 18-bit, fixed point architecture with multiply and divide. Memory was modularized into 8 kiloword modules, with a maximum of 64 kilo-words.
It was programmed in assembly language.