Ning Xianwen

Experiment research on heat-transfer capability of the multi-layer insulation blankets under different vacuum degrees

The high-speed reentry capsule of lunar spacecraft will face a weak vacuum environment long-term on orbit, thus the difference of heat-transfer capability of the multi-layer insulation blankets under different vacuum degrees should be evaluated in thermal design. In this article, an one-dimensional method of mesurement with adiabatic boundary condition was constucted to test the heat tranfer performance of multi-layer insulation blankets with 5, 10, 15 and 20 under 0.001-10000 Pa. Based on the test data, equivalent thermal conductivities of different vacuum degrees were calculated. The proper equivalent thermal conductivity is selected in the entire spacecraft thermal analyses, and this method is proved to be correct through thermal balance test and on orbit temperature telemetry. This work achieves not only basic data for reentry capsule, but also important fundation of thermal design and thermal analyse with multi-layer insultaion blankets in different vacuum degree.

Design and verification of thermal control system for Chang’E-3 probe

ChangE-3 probe is the first Chinese spacecraft landed on the lunar surface and survived for lunar day/night cycles. The ChangE-3 thermal control system developed new elements such as closed two-phase thermosyphons, variable conductance heat pipes (VCHP), high-temperature adiabatic shield and radioisotope heater units (RHU) to deal with the harsh environment. Ground test methods for simulating the effect of lunar gravity and descent engine were established as well. Thermal control system worked well in orbit and on the lunar surface, and maintained the probe components and structure within the required range of temperatures throughout the mission. First-hand data of the lunar surface probe, which is useful for the future mission, was obtained during the flight test. This paper introduces the primary requirements, chief factors and the characteristics of the thermal control system design. The final scheme, key elements and flight performance of thermal control system are also described.