High Performance Low Temperature Space Radiator (kTC P914)

The observation missions for the New Millennium Program will utilize new materials and sensor technologies that will require cooling to temperatures in the 40K to 150K range. A space radiator with high conductivity at low temperatures that is lightweight and has high stiffness is required. The opportunity presented in this Phase I proposal is to demonstrate a space radiator that will have high conductivity (>1800 W/mK) in the temperature region of interest (40K to 150K) and low density (< 2.0 g/cm3). Immediate payoffs include significant weight reductions and greater efficiency. This approach can also be used to improve the performance of low CTE optical benches; lightweight CTE matched heat spreaders for heat pipe evaporator and condenser ends, and thermal cores for electronic assemblies. These payoffs will allow for increased reliability and support the trend toward smaller less expensive satellites.The proposed material system is a macrocomposite comprised of thermal pyrolytic graphite (TPG) encapsulated within a carbon fiber composite structural shell. The pyrolytic graphite, TPG, is a unique form of graphite manufactured by decomposition of a hydrocarbon gas at high temperature in a vacuum furnace. TPG is highly aligned crystalline graphite with an in-plane thermal conductivity of 3000 W/mK at 120K. This is nearly 10 times the conductivity of copper. A radiator constructed of this material will provide high performance at a minimum weight.