Microengineering Technology for Space Systems: The Desire for a Mass Producible, Mass Customizable Nanosatellite

Abstract:

Since their invention nearly 60 years ago, glass ceramic materials have been used in a wide range of applications from human health (e.g., medical and dental) to consumer commodities (e.g., electronics) to transportation (e.g., aerospace). The material class has technological appeal since it is manufactured in the glassy amorphous phase and can be shaped via low cost “plastic” molding techniques, and then converted via a heat treatment step to the ceramic form. The photostructurable glass ceramics (PSGCs) are a subclass of the glass-ceramics. These materials include photo-sensitizer compounds that initiate the ceramization process. The advantage of the PSGC materials is that they can be lithographically patterned and the exposed areas can be subsequently converted into two ceramic phases, one of which is soluble in dilute hydrofluoric (HF) acid. Consequently, it is possible to fabricate intricate microstructures by lithographic or laser direct-write techniques. Because the material transformation process is photolytically initiated, other material properties can also be “turned on” on a local scale. In a recent series of experiments, we have explored the effect of controlling the irradiation exposure dose and the subsequent thermal processing protocol on three material properties for the commercially available PSGC FoturanTM. The material properties investigated are the optical transmission, the solubility in dilute acid, and the mechanical strength, with the goal to locally alter these properties to advantage in glass-ceramic microsystem applications. We have applied this knowledge in the development of a fully integrated cold gas propulsion system for a 1kg class nanosatellite vehicle that is largely made of PSGC materials. The micropropulsion system includes valves, electronics, wireless telemetry and a control system to demonstrate “leader-follower” or station keeping maneuvers on an air table. The use of the PSGC material as structural material for small satellites enables the manufacturing of nanosatellites in mass production by digital-direct-development technologies.