Summary

Description

<p>Thermal control of small spacecraft, including CubeSats, is a challenge for the next era of NASA spaceflight. Science objectives and components will still require strict thermal control while smaller volumes will inherently absorb and shed heat more quickly than a larger body. Thus, game-changing technologies must be developed to stabilize the thermal environment inside of small spacecraft. Developing this technology will help place Goddard at the forefront of thermal control expertise in the fast-growing arena of smallsats and CubeSats.</p><p>The proposed CubeSat louver assembly will be based upon the proven designs of full-sized louvers for large spacecraft. Internal spacecraft components will be thermally coupled to the side of the spacecraft. Bimetallic springs serve as a passive control mechanism for opening and closing flaps. As the spacecraft heats up the springs expand due to the difference in thermal expansion rates of their two fused metals (hence bimetallic). This opens the flaps, changing the thermal radiation properties of the exterior surface. As the spacecraft cools the flaps close and return the exterior surface to the previous emissivity. These temperature-driven adjustments create a more stable thermal environment for components.</p><p>Analysis of the thermal louvers assumed that the louvers were in darkness, either shielded by the solar panels or facing deep space. The hand calculations of power dissipated via the thermal louvers shows a substantial difference between fully closed and fully open louvers at the high temperatures significant for electrical components.</p>