Manned space missions require management of wide range of internal and external heat loads, necessitating advanced thermal control systems to maintain a certain environment regardless of external condition or mission phase. A morphing radiator capable of altering shape and the configuration of exposed surfaces could significantly increase radiator adaptability.
Shape memory alloys offer qualities that may be well suited for this endeavor; their temperature-dependent phase changes offer radiators the ability to passively control heat rejection. In previous efforts, the first ever morphing radiator prototype was constructed and tested in a thermal vacuum environment, where it successfully demonstrated the morphing behavior and variable heat rejection. Newer prototypes incorporating highly thermally conductive composite materials have more recently been designed and manufactured using two distinct types of SMA materials. The design process is complicated by the contradictory requirements of good radiator performance, which is associated with stiff, brittle materials and thick panels, and good morphing performance, which requires compliant structures. The successfully designed models underwent temperature cycling tests in a thermal vacuum chamber, and development is ongoing. This project was recently awarded a NASA Tipping Point grant in conjunction with Paragon Space Development Corporation, and Boeing Research and Technology to mature this novel adaptive thermal control technology (Full article here).
Other morphing radiator concepts are also being explored, including an annular flow SMA torque tube approach to panel reconfiguration.