IITMSAT is a student satellite being developed with a mission to measure charged particle energies and fluxes, and to study the precipitation of these particles from the Van Allen radiation belts. The Space-based Proton Electron Energy Detector (SPEED) is the payload detector aboard IITMSAT which is designed to carry out the mission of charge particle detection and energy measurement in low earth orbit (LEO). This paper details the design of the detector that meets the challenging requirements posed by the mission. © 2015 IEEE.