Design and Early In-flight Performance of the Tropical Rainfall Measuring Mission (TRMM) Power Subsystem

Maryland built the spacecraft in-house with four U.S. instruments and one Japanese instrument, the first space flown Precipitation Radar (PR). The TRMM Observatory was successfully launched from Tanegashima Space Center in Japan on an H-2 Expendable Launch Vehicle on November 27, 1997. This paper presents an overview of the TRMM Power System including its design, testing, and in flight performance for the first 70 days. Finally, key lessons learned are presented. The TRMM power system consists of an 18.1 square meter deployed solar array fabricated by TRW with Tecstar GaAs/Ge cells, two (2) Hughes 50 Ampere-Hour (Ah) Super NiCd' batteries, each with 22 Eagle-Picher cells, and three (3) electronics boxes designed to provide power regulation, battery charge control, and command and telemetry interface.