Variable Gas-Conductance Radiator: Lightweight, High Turndown Spacecraft Radiator

Spacecraft thermal control is a critical element to maintaining spacecraft, manned, unmanned or robotic, at proper temperatures for humans, instruments and electronics to function properly. Simple, passive thermal control in which excess heat is radiated to space via blackbody radiators used to be adequate, however, as spacecraft power levels increase and mission environments become more complex, more flexible and capable thermal control systems and mechanisms are needed. Variable heat rejection is an enabling technology to reliably vary heat rejection during human and robotic spaceflight missions with wide variation in thermal environments & vehicle heat loads. Quest Thermal Group is proposing a novel Variable Gas-Conductor Radiator (VGCR) that uses variable gas conduction within an IMLI structure to control heat conduction. A VGCR could provide both high and very low heat rejection, operating as both effective radiators and high performance insulation, and capable of turndown ratios of 76:1. The NASA 2012 TA14 Thermal Management Roadmap stated radiator advancement is perhaps the most critical thermal technology development for future spacecraft and space-based systems. NASA is seeking unique solutions for thermal control technology providing low mass highly reliable thermal control systems. As NASA moves beyond LEO, spacecraft must accommodate various mission scenarios and need variable heat rejection. Current state of the art variable radiators offer heat rejection turn-down ratios up to about 4:1. Phase I goals are to develop a new variable spacecraft radiator that can simply and efficiently provide a highly variable heat rejection using variable gas conduction within IMLI insulation, and prove feasibility of the VGCR concept to help improve radiator capabilities for future NASA and commercial spacecraft. A VGCR prototype will be modeled, designed, built and tested for thermal performance and variable heat rejection.