Microelectromechanical Devices for Satellite Thermal Control

TLDR

Future space missions will include constellations of spacecraft, including nano‑ and picosatellites, where adaptive thermal control systems will be needed that fit the constraints of space applications with limited power and mass budgets. The authors aim to develop and demonstrate a MEMS solution that varies the emissivity of small satellite radiators, with the first generation to be tested on NASA's New Millennium Program ST‑5 spacecraft. The system employs MEMS arrays of gold‑coated sliding shutters fabricated with Sandia's ultraplanar multilevel MEMS process, functioning as louver thermal controllers that mechanically adjust radiator surface area for digitally controlled emissivity. The demonstrator achieves up to a 40 % change in emissivity, with early prototypes indicating a wider dynamic range, and validation on ST‑5 could enable lightweight, low‑power MEMS radiators for flexible thermal control on future nanosatellites.

Abstract

Future space missions will include constellations of spacecraft, including nano- and picosatellites, where adaptive thermal control systems will be needed that fit the constraints of space applications with limited power and mass budgets. A microelectromechanical systems (MEMS) solution has been developed that will vary the emissivity on the surface of the small satellite radiator. The system is based on louver thermal controllers, where panels are mechanically positioned to modulate the effective radiator surface area. This system consists of MEMS arrays of gold-coated sliding shutters, fabricated with the Sandia ultraplanar, multilevel MEMS technology fabrication process, which utilizes multilayer polycrystalline silicon surface micromachining. The shutters can be operated independently to allow digital control of the effective emissivity. This first demonstrator technology is limited in the possible emittance range to a 40% change. Early prototypes of MEMS louvers that open away from the structure have shown the capability of a much wider dynamic range. The first generation of this active thermal management system will be demonstrated on NASA's New Millennium Program ST-5 spacecraft. With the opportunity to validate the MEMS thermal control technology in space on ST-5, lightweight, low-power MEMS radiators offer a possibility for flexible thermal control on future nanosatellites.