Geostationary communications platforms

In early 1984, NASA released two requests for proposal (RFPs) designed to answer several questions concerning geosynchronous (GEO) communications platforms. One RFP, released by NASA's Lewis Research Center, was designed to establish 'what aggregation of communications payloads, if any, would be appropriate for a commercial GEO communications platform in the mid- to late 1990s'. A second RFP, released by NASA's Marshall Space Flight Center, was designed to 'address the requirements for future spacecraft buses, space transportation systems and space operations capabilities necessary to enable GEO communications platforms'. The aggregated communications payloads developed in the NASA/Lewis study are briefly discussed, while primary attention is given to the results obtained to date in the NASA/Marshall platform bus studies.