Publisher Summary This chapter investigates the conic support in the radiant cooler by using finite element method. With the development of the cryogenic technology, the radiant cooler should provide lower temperature and more refrigerating output, which certainly will lead to the size of the radiant cooler become larger. Additionally, the stability of the support can be determined by several factors, like its size and shape etc. To better develop the radiant cooler along with the infrared remote sensing technology, a detailed consideration for the support is required. A domain of interest is repented as an assembly of finite elements. Approximating functions in finite elements are determined in terms of nodal values of physical field, which is sought. A continuous physical problem is transformed into a discretized finite element problem with certain nodal values. By optimizing the coning angle and the length of the support, one can amend the trade-off between its mechanical and thermal performance, which presents a possible pass to better develop the radiant cooler. Results show that the stiffness of the support increases with an increasing of the coning angle in case of launched state, while the situation is reversed in the orbited state. On the other hand, it is also found that the heat loss of the support caused by the thermal conduction decreases with the reduction of the coning angle.