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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Results of life tests of thermoelectric generators ranging in output power from 800 microwatts to 170 watts. Emphasis is placed on the results obtained from tests of three advanced prototypes - a high-performance generator, a transit-type generator, and a ring converter. In addition, the results of life tests of a number of generators representing Nimbus, Pioneer, and Viking technology are presented.
Dynamic method of measuring output power characteristics of radioisotope thermoelectric generator
Results of tests performed on a SNAP 19 thermoelectric generator, SN-20. The SN-20 generator was tested for approximately 37,000 hours using electrical heating to simulate the heat released by isotope decay. After 27,000 hours of operation the output power from the generator decreased to approximately 1/3 of the beginning of life value while the internal resistance increased by a factor of 5. Analysis of the test results, confirmed by preliminary metallographic examination, indicated that the output power degradation was the result of excessive sublimation of the thermoelectric material and loss of the hot junction bond due to the depletion of the internal cover gas. This also resulted in excessive junction temperatures. Comparison is made with the behavior observed from the two flight generators and a tentative conclusion is advanced as to the reason for their failure.
Flat plate solar thermoelectric generator for near-Earth orbits discussing theory, design, fabrication and testing
Design and performance equations for panel type solar thermoelectric generator, based on single thermocouple as generator unit
Deep space spacecraft radioisotope thermoelectric generators, discussing testing and evaluating for future missions
Performance tests of high temperature silicon- germanium alloy thermoelectric generator for outer planet mission spacecraft
Protective xenon atmospheres in sealed silicon- germanium alloy thermoelectric generators, discussing leakage and pressure levels
Seebeck effect solid state switch was developed eliminating thermoelectric generator switch voltage drops. Semiconductor switches were fabricated from materials with large Seebeck coefficients, arranged such that Seebeck potential is generated with such polarity that current flow is aided.
Flat plate solar thermoelectric generator panels for near-Earth orbit, discussing design and fabrication
Voltage transformation and power/energy utilization of radioisotopic thermoelectric generator source /RTG/ for space applications, analyzing components, inverter/converter circuits, etc
The successful utilization of a radioisotope thermoelectric generator (RTG) as the power source for spaceflight missions requires that the performance of such an RTG be predictable throughout the mission. Several mechanisms occur within the generator which tend to degrade the performance as a function of operating time. The impact which these mechanisms have on the available output power of an RTG depends primarily on such factors as time, temperature and self-limiting effects. The relative magnitudes, rates and temperature dependency of these various degradation mechanisms have been investigated separately by coupon experiments as well as 4-couple and 18-couple module experiments. This paper discusses the different individual mechanisms and summarizes their combined influence on the performance of an RTG. Also presented as part of the RTG long-term performance characteristics is the sensitivity of the available RTG output power to variations of the individual degradation mechanisms thus identifying the areas of greatest concern for a successful long-term mission.
The Mars Science Laboratory (MSL) Multi-Mission Radioisotope Thermoelectric Generator, or MMRTG, was developed by the Department Of Energy to a set of requirements from multiple NASA mission concepts. Those concepts included deep space missions to the outer planets as well as missions to Mars. The synthesis of that diverse set of requirements addressed functional as well as environmental requirements.
Reliability and efficiency of low input voltage inversion/conversion from radioisotopic thermoelectric generator power sources
Optimization of thermoelectric generators for fixed temperature and fixed heat input operation
Multihundred watt radioisotope thermoelectric generator for JPL outer planet missions, discussing vacuum/xenon filled performance and response to thermal/electrical transients
The Saturn-bound cassini spacecraft is designed to rely, without precedent, on the waste heat from its three radioisotope thermoelectric generators (RTGs) to warm the propulsion module sybsystem, and the RTG end dome temperature is a key determining factor of the amount of waste heat delivered.
INL has evaluated and refurbished General Purpose Heat Source (GPHS) Radioisotope Thermoelectric Generator (RTG) Flight Unit 5 (GPHS-RTG F5R or F5R) that was defueled in 2005. The generator has passed all the INL internal reviews, an end item data package has been delivered to NASA and is ready fueling for a mission. NASA requested a user’s guide for F5R with enough detail for a prospective mission proposal. This report documents the development of the power prediction model used in the user’s guide. The prediction evaluated the thermoelectric “burn-in” and the graceful degradation modes of the missions and developed a thermal inventory dependent equation that predicts the power that matches Galileo, Cassini, and PNH within a three-standard deviation of ±1%. This prediction is only valid for the 30 VDC load voltage of these missions.