Study of Solar Thermal Propulsion System Enhancement via Thermal Storage and Thermal-electric Conversion

摘要

Solar thermal propulsion (STP) systems optimized for microsatellites offer thrust and specific impulse combinations that exceed the capabilities of similarly sized, conventional chemical and electrothermal rockets. Past research into STP has indicated these advantages, with the caveats that propulsion can only be augmented during insolation and that a thermal power system competes with the traditional electric power systems required to support other spacecraft components. An STP system augmented with thermal storage and thermal-to-electric conversion is suggested and analyzed as a means to bypass these drawbacks. Targeting a temperature level of 1500-2500 K via solar concentration, such a system can yield a high-performance microsatellite with superior thrust and specific impulse (Isp) levels. It is shown that a phase- change thermal storage material can potentially be used to significantly surpass the energy density of traditional battery-powered systems. Coupled to a thermal photovoltaic system for electrical power, such a system can provide the advantages of STP along with meeting the requirements of traditional satellite payloads. Combined with the other efficiency advantages offered by STP, such a system has the potential to significantly enhance the capabilities of microsatellite systems while reducing mass and launch costs or increasing payload fractions.