Qualification and production of Emcore ZTJ solar panels for space missions

Abstract

Emcore's latest generation InGaP/InGaAs/Ge ZTJ triple-junction space-grade high-efficiency solar cells have been in volume production since 2009, with over 300,000 flight cells produced to power more than 35 separate satellites. The ZTJ cells, CICs (Coverglass-Interconnected-Cell) and solar panels have also been characterized and qualified to both the AIAA-S-111 and AIAA-S-112 standards. More than 10 life-cycle coupon panels have been thermal cycled to temperature extremes representing varied orbital conditions such as GEO (geosynchronous), LEO (low-earth) and highly elliptical orbits. In its larger 1-cell-per-wafer form factor, the ZTJ solar cell has been used to manufacture solar panels for a dozen NASA and other commercial spacecraft. Currently Emcore Photovoltaics is under contract to NASA's Goddard Space Flight Center (GSFC) to build and deliver the solar panels for the Magnetospheric Multiscale (MMS) Mission and to ATK Space Systems for the Commercial Resupply (CRS) mission to the International Space Station (ISS) and the AMOS-6 commercial telecommunication satellite. In this paper, the results of the qualification, production and testing of the life-cycle coupons and the solar panels for these missions is presented. In addition, the initial on-orbit telemetry performance results of NASA's NuStar (Nuclear Spectroscopic Telescope Array) spacecraft solar array will be presented. The NuStar spacecraft was launched in June of 2012 and built by Orbital Sciences Corporation It is powered by an ATK solar array populated with ZTJ solar cells.