Influence Factors of Temperature Difference between Ground Thermal Balance Test and Orbit Data of Spacecraft
- Paper number
IAC-08.C2.6.3
- Author
Mr. jun jiang, China Academy of Space Technology (CAST), China
- Coauthor
Mr. Qiang Liu, China Academy of Space Technology (CAST), China
- Year
2008
- Abstract
At present, there are temperature differences in spacecraft thermal balance test relative to the orbit data. Frequently, the temperature of the spacecraft in thermal balance test is lower than the orbit data. As a result, the thermal test data can not forecast the spacecraft temperature in orbit precisely. There are several impossible reasons such as a contaminated surface of the spacecraft during the ground test, the simulation error of outer heat flux in the thermal balance test and the environment simulation error, etc. In this paper, theoretical analysis and numerical simulation of radiation and conduction to a thin plate is explicated to the heat transfer of spacecraft. These analytic results reveal that there are differences between the real heat transfer and test simulation in which the average thermal flux of one orbit period is used. However, the simulation method is not the efficient reason for the lower temperature in thermal balance test compared with the orbit data. By means of the heat transfer analysis to rarefied air in the multilayer insulation, it is considered that the variety of vacuum will bring the change of heat loss through multilayer insulation. When the vacuum in the multilayer insulation is about 10**(-2)Pa, the heat loss resulted from to rarefied air will be extremely tiny. Nevertheless, when the vacuum trends 5**(-1)Pa, the heat loss will be an increase of 13% to the multilayer insulation heat loss. The test temperature of the spacecraft will be about 5 centigrade lower than the orbit data. Due to the vacuum in the multilayer insulation during thermal balance test in vacuum chamber is lower than that in space and the test time is usually shorter than the flight process, the heat loss through multilayer insulation is increased and hence lead to the module temperature falling. The spacecraft surface is covered with mass of multilayer insulation, the additional heat flux or the inner heat source should be added to assure the temperature data of ground test meeting the orbit temperature precisely. Several methods are presented to correct the heat loss in the thermal balance test resulted from lower vacuum in multilayer insulation in ground test than that in space.
Key Words: Average heat flux of one orbit period Thermal balance test Vacuum in Multilayer insulation
- Abstract document
- Manuscript document
IAC-08.C2.6.3.pdf (🔒 authorized access only).
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