Conditional extremum optimization analyses and calculation of the active thermal control system mass of manned spacecraft

The global lightweight optimization of the active thermal control system (ATCS) is of great importance to the manned spacecraft. The governing equations for the parameters that should be optimized for the minimum mass of the ATCS with dual liquid loops are established based on the energy conservation analyses, which makes the lightweight optimization become a conditional extremum problem. The ATCS mass equation is set up. The optimization equations are formulated by pursuing the extremum value of this mass equation and solved by the Newton iterative method. The optimization results for a typical ATCS in manned spacecraft are presented and the effects of the influencing parameters on the system mass are discussed. The results show that there is always an optimal value of the power consumption that leads to the minimum system mass, and the decrease in the specific mass of the power system leads to the reduction of the minimum system mass. The minimum system mass will reduce remarkably with decreasing total heat load or increasing working temperature of the thermal devices within a certain range.