High Performance CCSDS Processing Systems for EOS-AM Spacecraft Integration and Test

Abstract

The Earth Observing System-AM (EOS-AM) spacecraft, the first in a series of spacecraft for the EOS, is scheduled for launch in June of 1998. This spacecraft will carry high resolution instruments capable of generating large volumes of earth science data at rates up to 150 Mbps. Data will be transmitted in a packet format based upon the Consultative Committee for Space Data Systems (CCSDS) Advanced Orbiting Systems (AOS) recommendations. The Data Systems Technology Division (DSTD) at NASA's Goddard Space Flight Center (GSFC) has developed a set of high performance CCSDS return-link processing systems to support testing and verification of the EOS-AM spacecraft. These CCSDS processing systems use Versa Module Eurocard bus (VMEBus) Very Large Scale Integration (VLSI)-based processing modules developed for the EOS ground segment to acquire and handle the high rate EOS data. Functions performed by these systems include frame synchronization, Reed-Solomon error correction, fill frame removal, virtual channel sorting, packet service processing, and data quality accounting. The first of the systems was delivered in October 1994 to support testing of the onboard formatting equipment. The second and third systems, delivered in April 1995, support spacecraft checkout and verification. This paper will describe the function and implementation of these systems.