Digital onboard processor for directional charged particle flux measurements in space

Spacecraft-borne instruments for the measurement of directional particle flux distributions rely increasingly on digital onboard processors for improving their data collection efficiency. This paper describes in some detail a special purpose Data Processor from the point of view of how it complements the particle sensors for achieving optimum directional, energy and time measurements of interplanetary energetic proton fluxes. Particular attention is given to the implementation of establishing pseudosynchronism between data acquisition in spin-synchronous intervals and data transmission through the telemetry in order to achieve a 100% collection efficiency. (Auth.)