The Navy Navigation Satellite System (NNSS) uses precision quartz crystal oscillators to provide time and frequency in the orbiting spacecraft. The frequency changes for multiple oscillators, which were observed for 28 years of operational service in the orbital environment, are discussed. The primary frequency changes are believed to be caused by mass transfer to and from the resonator, stress relief in the resonator mounting structure and electrodes, and ionizing radiation of the quartz resonator. Observations to a resolution of 10- 13 have been made from 1963 to 1991 on 20 operational satellites in near-Earth orbit. No oscillator failures have occurred during the entire program life of nearly 30 years. One oscillator provided continuous operational service for over 21 years, and several have served more than 15 years. No oscillator changed frequency more than two parts in 107 while in operational service. One of the best performing oscillators had a predictable drift rate of 9*10-13+or-1*10-13 per day after three years of service.
Long-term performance of precision crystal oscillators in a near-Earth orbital environment
Langzeitverhalten von Präzisions-Quarzoszillatoren in Raumfahrtsystemen
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control ; 40 , 5 ; 528-531
1993
4 Seiten, 4 Quellen
Aufsatz (Zeitschrift)
Englisch
British Library Online Contents | 1994
|Orbital Debris Environment Predictions Based on a Long-Term Orbital Debris Evolution
British Library Conference Proceedings | 1996
|Long-Term Orbital Debris Environment Modeling Using EVOLVE 4.0
British Library Conference Proceedings | 2000
|