The End of an Era: SVN 10 End-Of-Life Frequency Standard Testing
Abstract
When SVN 10 was boosted into its disposal orbit on June 20, 1996, it marked the end of the first phase of the Global Positioning System (GPS) program. SVN 10 was the last of the operational Block I GPS satellites. On 18 November 1995, it was set unhealthy to users for the final time after being operational for over 11 years. Due to its solar array capacity degradation, SVN 10's electrical power subsystem was no longer able to support its navigation payload after more than double its design life of 5 years. Personnel at the Master Control Station (MCS) were able, however, to maintain a navigation signal long enough to perform several end-of-life tests on the four onboard frequency standards. These tests on the one cesium and three rubidium standards varied in length and complexity. Several of the tests continued research begun during SVN 9's end-of-life testing. Areas of interest included temperature coefficient determination, voltage-controlled crystal oscillator (VCXO) open-loop operations, new clock initialization, C-field and VCXO tune range determination, Ramsey pattern generation, frequency standard failure analysis, and clock reinitialization performance characteristic analysis. The results of these tests proved to be encouraging. After over 11 years in the space environment, there appeared to be no significant degradation to the navigation payload. Many of the test results supported conclusions made during SVN 9's end-of-life testing. It is hoped that these test results will prove to be useful to the GPS community by shedding more light on the performance characteristics of space-based frequency standards.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1996
- Accession Number
- ADA501446
Entities
People
- Gary L. Dieter
- M. J. Van Melle
Organizations
- 2d Space Operations Squadron