Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 273-292). / Communications satellite operators maintain archives of component telemetry to monitor system function. Operators generally do not typically use the telemetry data for scientific analysis of the space radiation environment effects on component anomalies or performance. We partnered with four geostationary (GEO) operators, acquired >1 million hours of telemetry, and combined these data with space weather observations to investigate relationships between space weather and hardware performance. We focused on the effects of space weather on two component types: solar cells and high power amplifiers. For solar cells, by augmenting >20 years of GEO telemetry with separate GEO space weather measurements, we calculated both on-orbit degradation of Si and GaAs solar cells in an annual average sense, and also quantified the degradation of cells during severe solar proton events (SPEs) of 10 MeV protons > 10,000 pfu. A functional relationship between the amount of degradation and proton fluence is also considered. We used the calculated degradation to evaluate several combinations of space weather environment models with solar cell degradation models and found that predicted performance is within 1% of the observed degradation. These models had not previously been validated using multiple on-orbit GEO datasets. We did not find a model pairing that consistently outperformed the others over all of the datasets. For high power amplifiers, through the use of statistical analysis, simulations, and electron beam experiments we conducted a root-cause analysis of solid state power amplifier (SSPA) anomalies on-board eight GEO satellites. From the statistical analysis, we identified that the occurrence of anomalies was not random with respect to the space weather environment, but that there appeared to be a relationship to high-energy electron fluence for periods of time between 10 - 21 days before the anomalies. From the simulations and electron beam lab tests, we demonstrated that internal charging occurs in the amplifier chain, potentially identifying a cause for the observed anomalies. We substantiated an approach toward understanding space weather effects on space components by obtaining and using long-duration archives of standard commercial telemetry for scientific analysis. The analysis of large telemetry data sets of similar components over long periods of time improves our ability to assess the role of different types of space weather events in causing anomalies and helps to validate models. The findings in this work that relate deep dielectric charging to component anomalies and solar proton events to solar cell degradation make use of only a small fraction of the potentially available commercial geostationary satellite telemetry. Expansion of this work would provide additional insights on the role of space weather to the science community and to the satellite design and operator community. / by Whitney Quinne Lohmeyer. / Ph. D.
| Identifer | oai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/98682 |
| Date | January 2015 |
| Creators | Lohmeyer, Whitney Quinne |
| Contributors | Kerri Cahoy., Massachusetts Institute of Technology. Department of Aeronautics and Astronautics., Massachusetts Institute of Technology. Department of Aeronautics and Astronautics. |
| Publisher | Massachusetts Institute of Technology |
| Source Sets | M.I.T. Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 292 pages, application/pdf |
| Rights | M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission., http://dspace.mit.edu/handle/1721.1/7582 |
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