Free-flying magnetometer data system architecture and hardware realization using commercial, off the shelf (COTS) technology

The Free-Flying Magnetometer (FFM) is an autonomous spin-stabilized “sensorcraft” developed for the Enstrophy sounding rocket mission. Four “hockey puck” FFMs were successfully ejected from the payload of a sounding rocket. The FFMs measured the vector magnetic field at 4 points separate from the payload at relative distances up to 3 km, and telemetered their data, in bursts, to the ground. This first-of-its-kind mission acquiring in-situ multipoint magnetic-field measurements employing multiple free-flying instruments is enabling new science by measuring the fine-scale structure of the currents in the ionosphere involved in the production of aurora. At the heart of the FFM is a sensitive 3-axis fluxgate magnetometer and an FPGA-based data subsystem that generates clocks and keeps a time for tagging data, implements and maintains sensor interfaces, and generates control signals to manage power and data flow. The data subsystem sequencing is implemented with a master state machine that connects, through prioritized handshake interfaces, to state machines that control the system resources. This paper discusses the FFM data system architecture and design, integration issues related to power, noise, and timing, and its implementation using COTS technology