Harmonic Drives are used ubiquitously in aerospace and robotics due to its high torque capacity, size and reduction ratio. However, their use in high radiation environments is still prone to failure. The literature on component and system reliability of space equipment is silent on the radiation induced failure of such gearboxes. This paper documents a new channel of radiation induced failure of harmonic drives which is relatively unexplored method of failure. We use the Master Curve Approach to calibrate the shift in upper shelf energy of the various material elements used in production of harmonic drive gearboxes. Estimations are made on the changes in fracture toughness based on various radiation environments. Radiation hardening could make
the gearboxes more resilient to neutron embrittlement of the SUS 304L Stainless Steel in flexspline. Our model shows that the gearbox system could wear out before its mission life in fast neutron radiation, where particle energies are in excess of 1 MeV. This type of radiation is fairly rare in large fluxes; while it does have a high enough flux in space to cause issues for humans, it is not high enough to appreciably impact steels. One of the few environments of interest for this effect is inside of nuclear reactors. Our study finds that without accounting for
neutron embrittlement, the predicted fatigue life of a harmonic drive can be off by nearly two orders of magnitude. From this model it was observed that when irradiated, the component strength of the harmonic drive will increase, while its fatigue life will decrease.