Deployer Performance Results for the TSS-1 Mission

Abstract

Performance of the Tethered Satellite System (TSS) Deployer during the STS-46 mission (July and August 1992) is analyzed in terms of hardware operation at the component and system level. Although only a limited deployment of the satellite was achieved (256 meters vs 20 kilometers planned), the mission served to verify the basic capability of the Deployer to release, control and retrieve a tethered satellite. - Deployer operational flexibility that was demonstrated during the flight is also addressed. Martin Marietta was the prime contractor for the development of the Deployer, under management of the NASA George C. Marshall Space Flight Center (MSFC). The satellite was provided by Alenia, Torino, Italy under contract to the Agencia Spaziale Italiana (ASI). Proper operation of the avionics components and the majority of mechanisms was observed during the flight. System operations driven by control laws for the deployment and retrieval of the satellite were also successful for the limited deployment distance. Anomalies included separation problems for one of the two umbilical connectors between the Deployer and satellite, tether jamming (at initial Satellite fly-away and at a deployment distance of 224 meters), and a mechanical interference which prevented tether deployment beyond 256 meters. The Deployer was used in several off-nominal conditions to respond to these anomalies, which ultimately enabled a successful satellite retrieval and preservation of hardware integrity for a future re-flight. The paper begins with an introduction defining the significance of the TSS-1 mission. The body of the paper is divided into four major sections: (1) Description of Deployer System and Components, (2) Deployer Components/Systems Demonstrating Successful Operation, (3) Hardware Anomalies and Operational Responses, and (4) Design Modifications for the TSS-1R Re-flight Mission. Conclusions from the TSS-1 mission, including lessons learned are presented at the end of the manuscript