MoonRanger’s radiation viability is achieved via component selection, shielding, short mission duration, testing, error correction and monitoring. Some components, including power management, primary and watchdog computers, accelerometer, and intelligent battery are selected for radiation tolerance, prior rad testing, or space heritage. Shielding is utilised for critical components that lack space heritage and boards developed by the program. MoonRanger takes advantage of the low total dose and relatively low probability of damage by high-energy particle hits resulting from short mission duration of 6-9 days in transit and less than 15 days on the lunar surface. The highest radiation dose rate occurs in transit through the Van Allen Belts, which is predicted to take 3-4 hours during which avionics is powered down. Our testing has irradiated critical components to 4x mission TID and greater exposures are planned. Independent testing determined that the central computer survives a multiple of the predicted high energy and TID exposure. The central computer has built-in error correction. Load current is monitored for latch-up detection and subsequent reset for recovery.
For detailed information view the PDF: MR-AVI-0068_Radiation Survival Summary.