Calculation of external heat fluxes on space camera with two-dimensional changing attitudes in sun-synchronous orbit

In order to get accurate data of external heat fluxes on space camera with two-dimensional changing attitudes, a method was proposed to calculate the external heat fluxes of space camera with two-dimensional changing attitudes in J2000 coordinate system. First, in J2000 coordinate system positions of space camera, position and radiation intensity of sun were calculated. Second, according to the working characteristics of the space camera whose visual axis always points to the sun and the position of the sun, its two-dimensional attitude angles were calculated under extreme conditions. Then, based on the obtained attitude angles, the attitude transformation matrix was calculated. Finally, in one orbital period external heat fluxes of unchanging attitude and two-dimensional changing attitudes were calculated with Matlab programming. The external heat fluxes of this paper were in good agreement with I-deas/TMG software. Compared with the unchanging attitude camera, external heat fluxes of the two-dimensional changing atitudes camera will have a great change, especially for the -Y surface where optical entrance is located. The solar radiation heat fluxes fluctuation range of -Y surface is 0-1 394 W/m2. The obtained attitude angles provide an important reference for the adjustment of the attitude for the thermal simulation model. According to the data of the external heat flux with changing attitudes, it can be seen that the external heat fluxes of the -Z surface is smallest, and the maximum average period external heat fluxes of -Z surface is less than 4 W/m2. In addition, the external heat fluxes of the X surfaces and +Y surface are smaller, and the maximum average period external heat fluxes of X surfaces are less than 80 W/m2, and the maximum average period external heat fluxes of +Y surface are less than 110 W/m2. In practical application, the external heat fluxes of X surfaces and +Y surface will be smaller due to the obstruction of the satellite platform. Therefore, the -Z surface, X surfaces and +Y surface can be used as heat dissipation surfaces, which provides a good guide for thermal design work.