Abstract: For the Mars surface exploration, the Martian atmosphere absorbs and scatters the incident solar radiation, while causing convective heat transfer between itself and the spacecraft on the surface of Mars. In the thermal design, it is difficult to directly assess the impact of the three heat transfer types (convection, radiation and heat conduction) on the spacecraft and determine the main transmission ways. Based on the investigation into the thermal environment such as Mars surface radiation and the atmosphere, the effects of radiation, convection and heat conduction on the spacecraft were compared and analyzed from the perspective of linearized heat transfer coefficient and convection-radiation ratio. The radiation heat transfer coefficient of the spacecraft surface varies with optical properties and temperature in the range of 0.3W/(m²·℃) to 1.4W/(m²·℃), and the convective heat transfer coefficient varies with the wind speed from 0.2W/(m²·℃) to 1.5W/(m²·℃). The conduction heat transfer coefficient can be controlled below 0.25W/(m²·℃). The results show that solar radiation is the main external heat source compared to Mars surface and sky radiation. Radiation and convective heat transfer on the surface of the spacecraft are two parallel transmission paths, both of which may become the main path. The heat conduction in the spacecraft is the main controllable factor of its thermal control.

Key words: Mars, thermal environment, convection heat transfer, radiation heat transfer, conductivity heat transfer, spacecraft thermal control