Effects of radiation on performance of space-borne quartz crystal oscillators

An essential component of any space vehicle is the onboard master oscillator. The proper operation of the entire payload is dependent on the performance of the master oscillator (or onboard clock). One of the major concerns for quartz clocks in space is the effect of space radiation. Quartz is inherently sensitive to naturally occurring radiation in space. The exact nature of the radiation experienced in space is a function of the orbital dynamics of each particular application, and the impact of that radiation on quartz oscillator performance depends on each particular mission's requirements. Extensive tests on Earth have revealed some very interesting results that can be used to predict performance in space. This has made possible the development of a radiation compensated quartz crystal oscillator, with improved frequency aging performance. The frequency aging rate is extremely important for predicting the expected performance of these oscillators after 10 or 15 years in space. In this paper we will present data on the effects of oscillator aging-rate performance when subject to some commonly encountered space radiation environments.