Thermal Analysis for the Laser Microreflector Array onboard CRISTAL satellite (Copernicus polaR Ice and Snow Topography Altimeter)

CRISTAL mission (Copernicus polaR Ice and Snow Topography ALtimeter) whose launch is planned for 2028, will be crucial for monitoring the cryosphere. Its primary payload consists of three main instruments: a dual frequency Interferometric Radar altimeter for Ice and Snow (IRIS) operating in the $\mathrm{Ku}(\sim 13.5 \mathrm{GHz})$ and Ka -bands ($\sim 35.75 \mathrm{GHz}$), each with a bandwidth of 500 MHz; a passive microwave radiometer (MWR) with atmospheric corrections capabilities; a global navigation satellite receiver (GNSS) providing on-board timing. Additionally, the payload includes a Laser Retroreflector Array (LRA), used for laser ranging to validate the orbit. In this paper, we focus on the thermal study conducted for the thermal qualification of the LRA.