1、Lessons Learned Entry: 0908Lesson Info:a71 Lesson Number: 0908a71 Lesson Date: 2000-08-01a71 Submitting Organization: GSFCa71 Submitted by: Dave CoolidgeSubject: NOAA-15(K) S-Band Antenna Failure Description of Driving Event: The NOAA-15 (K) satellite was launched on May 13 1998. The satellite was t
2、he first in the new series of Polar Operational Environmental Satellites (POES) that had design heritage back to Tiros-N launched in 1978. NOAA-15, however, had three S-band antennas operating in the 1700 MHz frequency range that were new to this mission.Approximately 18 days after launch, data qual
3、ity degradation was noted during tape recorder playbacks on the S-band #2 link. In October science data from the AMSU-B instrument provided by the UK was observed to have contamination toward one side of the scan field of view. The degradation was consistently evident or not depending upon the satel
4、lite orbital location. An Anomaly Review Board was established and investigation revealed that the contamination appeared to rotate around the globe as the sun moved from north to south during the annual season change.Further investigation revealed a thermal correlation to the link degradation and s
5、cience data contamination as the S-band antennas experienced large thermal gradients throughout the orbit. A detailed thermal stress analysis performed for the antenna confirmed stress levels within internal connecting elements that were sufficient to cause breakage. Once broken, changes in antenna
6、gain, axial ratio, and SWR would significantly degrade link performance and antenna patterns. The failure mode was confirmed in a thermal cycling test of a flight antenna.Lesson(s) Learned: 1. Designers of satellite elements subjected to significant thermal gradients in orbit must carefully consider
7、 the coefficients of thermal expansion (CTE) of all components in the design.2. A detailed thermal model must be constructed that accurately reflects in orbit temperature Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-extremes and gradients that the
8、 element will experience.3. A detailed mechanical model must be constructed that accurately models both mechanical and thermal stresses within the element.4. For elements subjected to frequent and large thermal excursions, additional qualification testing in the form of thermal cycling should be con
9、sidered.Recommendation(s): Ensure that new flight hardware is subjected to a rigorous and well-documented peer and design review process.Evidence of Recurrence Control Effectiveness: 1. The antennas were redesigned with materials that matched closely in CTE characteristics.2. The new antenna success
10、fully completed qualification that included an extensive thermal cycling test.Documents Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Sciencea71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Communication Systemsa71 Configuration Managementa71 Fligh
11、t Operationsa71 Hardwarea71 Parts Materials & Processesa71 Spacecrafta71 Test & VerificationAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2000-09-18a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
