Session
Technical Session VII: 11th Annual Frank J. Redd Student Scholarship Competition
Abstract
In the fall of 2001, the author embarked on an investigation of small (< 100 kg) satellites augmented with high-performance solar thermal propulsion (STP). Small satellites have historically been confined to low earth orbits, with only a very limited capability to alter orbital parameters. A solar thermal propulsion system, properly downsized, could enable microsatellites to perform missions to high earth orbit, as well as lunar, near earth asteroid, and interplanetary intercepts, without the aid of expensive upper stages. Specific impulses of up to 400 seconds (s) are theoretically achievable, with storable monopropellants; velocity changes of up to 3,000 m/s may therefore be attained. This paper will briefly review a selection of benchmark missions and their requirements, and the preliminary and detailed design choices including specific ground rules. However, the focus of the paper is on recent component test results in three key areas: (1) novel ceramic gasketing and metal-to-ceramic bonding methods, a necessity for hermetically sealing the solar thermal cavity receiver; (2) optical performance measurements of a lightweight metal solar concentrating mirror; and (3) thermal performance measurements of the insulated cavity receiver in a series of electrical heating tests in vacuum. A comparison of test data will be made to the results of the author’s optical and thermal models, demonstrating strong agreement between predicted and actual results. These results strongly suggest that solar thermal propulsion can in fact provide substantial orbit transfer capability to small satellites.
Presentation Slides
An Analysis of Preliminary Test Campaign Results for a Microscale Solar Thermal Engine
In the fall of 2001, the author embarked on an investigation of small (< 100 kg) satellites augmented with high-performance solar thermal propulsion (STP). Small satellites have historically been confined to low earth orbits, with only a very limited capability to alter orbital parameters. A solar thermal propulsion system, properly downsized, could enable microsatellites to perform missions to high earth orbit, as well as lunar, near earth asteroid, and interplanetary intercepts, without the aid of expensive upper stages. Specific impulses of up to 400 seconds (s) are theoretically achievable, with storable monopropellants; velocity changes of up to 3,000 m/s may therefore be attained. This paper will briefly review a selection of benchmark missions and their requirements, and the preliminary and detailed design choices including specific ground rules. However, the focus of the paper is on recent component test results in three key areas: (1) novel ceramic gasketing and metal-to-ceramic bonding methods, a necessity for hermetically sealing the solar thermal cavity receiver; (2) optical performance measurements of a lightweight metal solar concentrating mirror; and (3) thermal performance measurements of the insulated cavity receiver in a series of electrical heating tests in vacuum. A comparison of test data will be made to the results of the author’s optical and thermal models, demonstrating strong agreement between predicted and actual results. These results strongly suggest that solar thermal propulsion can in fact provide substantial orbit transfer capability to small satellites.
