5.4 Design Methodology
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8. Thermal Control Solution for Exposed Parts
The exposed parts of the lunar lander ere mechanisms, antennas, sensors and optical
devices such as cameras. Generally, the solar panel mechanism and some antennas
should work normally again after experiencing harsh environment in lunar night.
Different exposed parts had different temperature requirement and various environmental conditions, therefore, independent thermal design as required. In order to
reduce the impact on main body of the lunar lander, the exposed components were
generally installed with insulation to the lunar lander. For exposed parts with special
requirements for temperature during lunar night, a small RHU could also be used to
provide heat to ensure that the temperature requirement was met.
Compared with Earth orbit and circumlunar spacecraft, due to the harsh environment during the lunar daytime and nights and large cost, it was impossible to take
measures to ensure that each exposed component was in a similar temperature environment to other spacecraft. Generally, it was necessary for exposed parts of the lunar
lander to withstand more severe temperature ranges and be verified experimentally.
5.4.3 Thermal Analysis and Calculation
The thermal analysis and calculation was an important means to verify the thermal
design of the lunar lander. Its objective was to determine the temperature change
pattern of each part in the lunar lander according to the thermal conditions inside
or outside the lunar lander and the thermal control measures. It was also to check
whether the thermal design had kept the various parts controlled within the required
temperature range and to predict the actual operating temperature of the lunar lander.
Due to the complex flight process of the lunar lander and uncertainty of landing attitudes, the thermal balance test couldn’t cover all flight events. The thermal analysis
model could only be modified based on limited thermal test conditions, and then
give the temperature prediction for various flight phases and task. The thermal analysis generally ran through the entire development process of the lunar lander. After
launch and orbit injection of the lunar lander, according to flight control requirement,
the results of thermal analysis were required to provide the basis for dealing with
flight events. After landing, it was necessary to predict the subsequent temperature
conditions based on actual attitude. Therefore, the thermal analysis and calculation
was an important task for development of thermal control subsystem in the lunar
lander.
Like other spacecrafts, the thermal network analysis method was the major
approach for thermal analysis of the lunar lander. Currently, many mature commercial
software of thermal analysis was available for modeling and calculation. However,
secondary development on the basis of existing commercial software might be necessary for calculation of lunar surface temperature field in order to conduct the thermal
analysis calculation in circumlunar and lunar surface phases.
169
8. Thermal Control Solution for Exposed Parts
The exposed parts of the lunar lander ere mechanisms, antennas, sensors and optical
devices such as cameras. Generally, the solar panel mechanism and some antennas
should work normally again after experiencing harsh environment in lunar night.
Different exposed parts had different temperature requirement and various environmental conditions, therefore, independent thermal design as required. In order to
reduce the impact on main body of the lunar lander, the exposed components were
generally installed with insulation to the lunar lander. For exposed parts with special
requirements for temperature during lunar night, a small RHU could also be used to
provide heat to ensure that the temperature requirement was met.
Compared with Earth orbit and circumlunar spacecraft, due to the harsh environment during the lunar daytime and nights and large cost, it was impossible to take
measures to ensure that each exposed component was in a similar temperature environment to other spacecraft. Generally, it was necessary for exposed parts of the lunar
lander to withstand more severe temperature ranges and be verified experimentally.
5.4.3 Thermal Analysis and Calculation
The thermal analysis and calculation was an important means to verify the thermal
design of the lunar lander. Its objective was to determine the temperature change
pattern of each part in the lunar lander according to the thermal conditions inside
or outside the lunar lander and the thermal control measures. It was also to check
whether the thermal design had kept the various parts controlled within the required
temperature range and to predict the actual operating temperature of the lunar lander.
Due to the complex flight process of the lunar lander and uncertainty of landing attitudes, the thermal balance test couldn’t cover all flight events. The thermal analysis
model could only be modified based on limited thermal test conditions, and then
give the temperature prediction for various flight phases and task. The thermal analysis generally ran through the entire development process of the lunar lander. After
launch and orbit injection of the lunar lander, according to flight control requirement,
the results of thermal analysis were required to provide the basis for dealing with
flight events. After landing, it was necessary to predict the subsequent temperature
conditions based on actual attitude. Therefore, the thermal analysis and calculation
was an important task for development of thermal control subsystem in the lunar
lander.
Like other spacecrafts, the thermal network analysis method was the major
approach for thermal analysis of the lunar lander. Currently, many mature commercial
software of thermal analysis was available for modeling and calculation. However,
secondary development on the basis of existing commercial software might be necessary for calculation of lunar surface temperature field in order to conduct the thermal
analysis calculation in circumlunar and lunar surface phases.