Different preservation temperatures for sample storage in space stations and corresponding refrigerator devices have been designed. In the below-freezing environment, frost will occur on the inner wall surface and the sealing place of the refrigerator device, which may have an impact on the operating performance and sealing performance of the refrigerator device. This paper analyzes the impact of frost on refrigerator storage devices, and designs and verifies a scheme of air cooling with a hollow seal method to reduce the impact of frost. The designed refrigerator was tested for air cooling, sealing, and long-term performance. The tests show that the air-cooling structure designed in this paper can effectively reduce the frost on the sample surface. A cumulative helium mass spectrometry leak detection method is applied to verify that the hollow seal structure designed has a better sealing property, which can prevent the diffusion of water vapor and frosting at the sealing position. The design with air cooling and hollow sealing has less frost and more stable performance for long-term operation. The results demonstrate this refrigerator would have the capability of operating on-orbit. The frost-preventing method for space station refrigerator designed in this paper has significance for the design of similar cryogenic equipment in microgravity environments.

The supply and exhaust system of the experimental rack on the Chinese space station is a complex integrated system. In this paper, a multi-stage simulation, testing, and verification method is designed for a multi-team, multi-location, and multi-stage integrated gas system. This method is designed to solve the problem of missing input parameters between the gas supply system and the exhaust system. Preliminary tests and strategy verifications were carried out through theoretical simulation and semi-physical simulation, and good calculation results were obtained for the single-rack product. The external systems were tested using a simulation system, and a calculation method was designed to obtain relatively accurate parameters. In the early stage, the performance of the product was predicted using the parameter library of Flomaster and semi-physical simulation methods, but the error was large. In the middle and late stages of development, as some products became realistic, multi-stage testing was carried out using a vacuum simulator, simulated flow resistance, and other methods, achieving a performance prediction with an error of 12% before ground testing. The final ground test and on-orbit test showed that the design and calculation method of this paper is effective. The multi-stage design method proposed in this paper was successfully applied to the integrated gas system of the Chinese space station, which can provide a reference for the design of fluid components in long-term system engineering.

As an important mission of space stations, space science experiment usually requires effective temperature control measures. Scientific experimental express rack (ER) is a general design for space science experiment. In some space scientific experiments, the temperature of local target element or surrounding exceed heat sink temperature range, effective heating and cooling measures are required. Thermoelectric cooler (TEC) has high reliability and low complexity, which is applicable for temperature control in low gravity conditions. In the ER, the entire surrounding is indirectly heated or cooled by the ambient air, local target element surface is heated or cooled by liquid, TEC is thermal competent for ER thermal control attributed to the low complexity and high reliability, which can enlarge the temperature range of air and liquid. In this paper, a modular integrated thermal control system (MITCS) is designed for a specific ER, which has liquid assembly (LA), TEC assembly (TECA), heat exchanger assembly (HXA) and air cycle assembly (ACA) to provide target surface cooling and heating, entire surrounding cooling and heating. The thermal performance of MITCS using TEC are analyzed, providing guides for the design of the scientific experimental ER and other thermal systems.