Hermes (Hybrid/Mk V)

Hermes was designed to handle data acquisition and control at the forward end of the Mk V/Starscraper rocket. The board performs several major functions, including control of the oxidizer tank pressure regulator valve and vent valve, the roll control system (RCS), and the recovery system; as well as recording temperature and pressure data and relaying information to the telemetry downlink system.

The brains of Hermes is an ARM Cortex-M4 microcontroller with 128 Mb NOR flash for storage.  The oxidizer tank pressure regulator and vent valve are actuated by two servo motors. The pressure and temperature of the oxidizer is measured through the use of pressure transducers and thermocouples. The roll control system is governed by the switching of two solenoid valves which Hermes controls using power FETs, which are heat sinked as the solenoid valves require a significant amount of power. Finally, Hermes was responsible for the deployment of the recovery system, through the firing of electric matches to detonate explosive bolts. This releases the nose cone from the main body of the rocket and deploys the parachute.