On-orbit thermal environment analysis of the optical bench of a new generation of gravity measurement satellites

The new generation of gravity measurement satellites will use high-precision inter-satellite laser interferometry technology to measure the gravity field. The heat flow outside the satellite's orbit will act on the optical bench (OB) through laser emission and reception apertures and introduce the temperature noise of the measurement signal. Based on modeling the orbital thermal environment at the incoming aperture and outgoing aperture of the laser designed on the spacecraft front panel, baffles are designed to reduce the heat flow from the apertures into the optical measurement system. The temperature noise of the optical bench caused by space radiation during on-orbit operation was analyzed using finite element simulation software. For the current design of the baffles, the temperature noise of the optical bench is lower than 0.1 K/Hz^1/2@1 mHz when the direct solar radiation enters the apertures; when the apertures are in the light-blocking environment, the temperature noise of the optical bench is lower than 0.1 mK/Hz^1/2@1 mHz, which meets the temperature noise requirement of a laser interferometer. The baffles are designed to achieve a stable shading period of up to 4 months in a year to facilitate the satellite to carry out ranging work.