The Global Precipitation Measurement (GPM) Spacecraft Power System Design and Orbital Performance

¹ AS&D, Inc. Seabrook, MD 20706 USA
² NASA Goddard Space Flight Center, Code 563, Greenbelt Road, Greenbelt, Maryland 20771 USA

^* Email: george.dakermanji-1@nasa.gov
^** michael.g.burns@nasa.gov
^*** leonine.s.lee@nasa.gov
^**** john.w.lyons@nasa.gov
^***** david.kim@nasa.gov
^****** thomas.j.spitzer@nasa.gov
^******* bradford.p.kercheval@nasa.gov

Abstract

The Global Precipitation Measurement (GPM) spacecraft was jointly developed by National Aeronautics and Space Administration (NASA) and Japan Aerospace Exploration Agency (JAXA). It is a Low Earth Orbit (LEO) spacecraft launched on February 27, 2014. The spacecraft is in a circular 400 Km altitude, 65 degrees inclination nadir pointing orbit with a three year basic mission life. The solar array consists of two sun tracking wings with cable wraps. The panels are populated with triple junction cells of nominal 29.5% efficiency. One axis is canted by 52⁰ to provide power to the spacecraft at high beta angles. The power system is a Direct Energy Transfer (DET) system designed to support 1950 Watts orbit average power. The batteries use SONY 18650HC cells and consist of three 8s × 84p batteries operated in parallel as a single battery.

The paper describes the power system design details, its performance to date and the lithium ion battery model that was developed for use in the energy balance analysis and is being used to predict the on-orbit health of the battery.