SAE International Thermal Simulation of Asteroid Surface Temperature and Yarkowski Effect 2009-01-2567

The thermal environment on or near the surface of the solar system bodies, such as Near Earth Orbit (NEO) asteroids has important implications on future plans for a variety of solar system explorer missions. These missions aim to study asteroids, the primitive leftover building blocks of the Solar System formation process, to understand and potentially alter the course of an object that may threaten the Earth, or to demonstrate the technology to pave the way for man's return to Earth's Moon and beyond. Previous work to determine the surface temperatures of asteroids has addressed the needs of astronomy by using the IR emission from the asteroid to determine its size. However this simulation assumes a theoretical spherical asteroid and not the complex geometries often observed. The simplification leads to inaccurate temperature prediction of details features of the asteroid surface which are of significance to vehicles and orbit prediction. Astrium UK has been involved in various studies for spacecraft and landers that must operate within the demanding environment of these solar system bodies. During the course of these studies thermal simulation of asteroids themselves has been undertaken to determine the surface environment of irregular bodies and predict its effect on the orbit. Determination of asteroid surface temperature leads to improved determination of orbital paths as the heat radiated from the surface can alter the course of these objects via the Yarkowski effect. Analytical models of the Yarkowski effect exist only for a few simple cases and a numerical thermal model of the real asteroid is required for accurate orbit predictions. This paper discusses the thermal environment encountered on the surface of these solar system bodies including the effect this environment has on its own orbital motion.