Technologies for Cooling of Large Distributed Loads

In future space applications, large and distributed loads will require active thermal control if their lifetimes are to be extended beyond one or two years. Examples include Zero Boil-Off (ZBO) cryogenic systems for exploration missions, and cooling of widely distributed sensor arrays and large deployable structures, such as mirrors and sunshades, for space science missions. These applications will require efficient means of heat transfer from extended structures or from several discrete elements to one or more remotely located heat rejection packages consisting of active and passive components. More or less stringent temperature control will also be required. We have recently undertaken a program to develop a number of technologies relevant to the issues associated with distributed cooling. These include circulation networks that transfer heat via steady flows of cold pressurized gas; gas rectifiers for use with linear pressure wave generators; and MEMS-based throttling valves for precise temperature control. This paper describes the studies that are underway to establish the performance potential of each.