Performance of the Magnetospheric Multiscale central instrument data handling

In order to study the fundamental physical processes of magnetic reconnection, particle acceleration and turbulence, the Magnetospheric Multiscale (MMS) mission employs a constellation of four identically configured observatories, each with a suite of complementary science instruments. Southwest Research Institute^® (SwRI^®) developed the Central Instrument Data Processor (CIDP) to handle the large data volume associated with these instruments. The CIDP is an integrated access point between the instruments and the spacecraft. It provides synchronization pulses, relays telecommands, and gathers instrument housekeeping telemetry. It collects science data from the instruments and stores it to a mass memory for later playback to a ground station. This paper retrospectively examines the data handling performance realized by the CIDP implementation. It elaborates on some of the constraints on the hardware and software designs and the resulting effects on performance. For the hardware, it discusses the limitations of the front-end electronics input/output (I/O) architecture and associated mass memory buffering. For the software, it discusses the limitations of the Consultative Committee for Space Data Systems (CCSDS) File Delivery Protocol (CFDP) implementation and the data structure choices for file management. It also describes design changes that improve data handling performance in newer designs.