Investigation of a model of the Soyuz spacecraft washed by the control jets of the Apollo spacecraft

Abstract

During mission design for the joint flight of the Soyuz and Apollo spacecraft in the EPAS program, a preliminary analysis was made of the thermal and force interactions of the motor jets of the Apollo control system on the Soyuz spacecraft. It was shown that the flow over the service, command, and docking modules of Apollo formed shock waves which intersected the communication antennas, the solar cells, and other structural elements of Soyuz during the docking. The flight program provided for possible simultaneous operation of four motors of the control system. In that case the jets interact, forming a complex three-dimensional flow. In the regions where shock waves interact with the Soyuz structural elements, the local convective heat fluxes, which are significant in magnitude, increase, since the temperatures and pressures in the Apollo engine combustion chambers are ∼3000 °K and 7·105 Pa, respectively. The need for reliable operation of all devices of Soyuz located in the jet interaction zone required experimental investigations to be performed to determine the heat flux to the structure and the surface pressures on the spacecraft, with particular attention being paid to modeling of the phenomena. It should be noted that the results of analogous investigations carried out earlier by the USA with reference to the manned lunar flight program could not be used because of the difference of the Soyuz geometry and the newly developed docking module in the EPAS mission from the Apollo lunar module geometry.