The current paper presents an overview of the thermal model and analysis of the extreme thermal environment of the planet Mercury. Due to the close proximity of the Sun, the Solar irradiation fluxes received by spacecraft orbiting Mercury will be up 10 times higher than those observed in an Earth orbit. In addition, very high temperatures are expected to be experienced by the spacecraft (up to 700 K), due to the combination of solar irradiance and close proximity (close to periherm) to the Ssunlit surface of Mercury.
Such extreme thermal environment, very different from the typical boundary conditions on Earth, make it difficult to predefine the worst case scenarios for different instruments.
Therefore, this paper addresses the thermal analysis and results of typical nadir-looking payloads, with different capacitances, orbiting Mercury. The fluxes (solar, albedo and Infra-Red) and temperatures are analysed as a function of both the true anomaly of the spacecraft around Mercury and also of the true anomaly of planet around the Sun. Worst thermal configurations are identified.