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5 Thermal Control Technology of Lunar Lander
5.5.2 Protection Technology for High-Temperature Engine
During LOI and soft-landing, large engine was used by the lunar lander to decelerate
with small thrusts (such as 150 N and 10 N thrusters) for attitude control and landing
assistance. During LOI and soft-landing, due to long duration and high temperature
of engine nozzle that could be higher than 1300 °C, high temperature insulation
shield could be effective to insulate main body of the lunar lander with engine high
temperature for protection up to date.
The high-temperature insulation shield was a multilayer heat insulation material
that could withstand the high temperature of engines. In order to reduce the weight, the
material of reflective screen and the spacer layer at different positions was optimized.
The performance and characteristics of high-temperature insulation shield factors
was the same as conventional multilayer insulation. Compared with conventional
multilayer thermal insulation, in design of high temperature insulation shields for
engines in structure, the configuration of heat shield should minimize blockage of the
engine, so that the engine surface could radiate heat as much space as possible. The
thermal shield material should be able to withstand high temperatures during fire of
engines, and the volatilization of metal at high temperature should meet requirement.
In addition, the high temperature thermal shield was generally fixed on bracket. The
method of fix should minimize the heat leakage and meet the temperature limit of
fixed bracket.
The performance of high-temperature insulation shield is related to the number
of layer units. For thermal shield of engines, the lag of temperature response caused
by heat transfer lag in the thickness direction is an important feature of the hightemperature insulation shield besides heat leakage. The thermal analysis method is
generally used to predict temperature response and verified by vacuum thermal test
when thermal shield is developed.
Due to configuration limitations, major part of the 7500 N landing engine was
embedded inside the Chang’E-3 lunar lander resulting in protection issues of high
temperature. The relative position of the high-temperature insulation shield to the
engine is shown in Fig. 5.13. When the engine was firing, the surface temperature
of high-temperature insulation shield opposite the engine throat was higher than
1000 °C.
High-temperature insulation shields were one of key components for safe landing
of the Chang’E-3 lunar lander, whose thermal insulation properties were crucial
to the landing process. High-temperature insulation shield was composed of highresistance insulating materials. Heat insulation effects and mass reduction were
considered, and the mass was reduced as much as possible in the premise of heat insulation performance requirement satisfied when high-temperature insulation shield
was designed. When the 7500 N engine was firing, the high temperature of engine
nozzle was insulated from main body of the lunar lander. Only a small amount of
heat was introduced into the lunar lander through the high-temperature insulation
shield to ensure that the temperature of structure and instruments in modules would
not be higher than requirement.
5 Thermal Control Technology of Lunar Lander
5.5.2 Protection Technology for High-Temperature Engine
During LOI and soft-landing, large engine was used by the lunar lander to decelerate
with small thrusts (such as 150 N and 10 N thrusters) for attitude control and landing
assistance. During LOI and soft-landing, due to long duration and high temperature
of engine nozzle that could be higher than 1300 °C, high temperature insulation
shield could be effective to insulate main body of the lunar lander with engine high
temperature for protection up to date.
The high-temperature insulation shield was a multilayer heat insulation material
that could withstand the high temperature of engines. In order to reduce the weight, the
material of reflective screen and the spacer layer at different positions was optimized.
The performance and characteristics of high-temperature insulation shield factors
was the same as conventional multilayer insulation. Compared with conventional
multilayer thermal insulation, in design of high temperature insulation shields for
engines in structure, the configuration of heat shield should minimize blockage of the
engine, so that the engine surface could radiate heat as much space as possible. The
thermal shield material should be able to withstand high temperatures during fire of
engines, and the volatilization of metal at high temperature should meet requirement.
In addition, the high temperature thermal shield was generally fixed on bracket. The
method of fix should minimize the heat leakage and meet the temperature limit of
fixed bracket.
The performance of high-temperature insulation shield is related to the number
of layer units. For thermal shield of engines, the lag of temperature response caused
by heat transfer lag in the thickness direction is an important feature of the hightemperature insulation shield besides heat leakage. The thermal analysis method is
generally used to predict temperature response and verified by vacuum thermal test
when thermal shield is developed.
Due to configuration limitations, major part of the 7500 N landing engine was
embedded inside the Chang’E-3 lunar lander resulting in protection issues of high
temperature. The relative position of the high-temperature insulation shield to the
engine is shown in Fig. 5.13. When the engine was firing, the surface temperature
of high-temperature insulation shield opposite the engine throat was higher than
1000 °C.
High-temperature insulation shields were one of key components for safe landing
of the Chang’E-3 lunar lander, whose thermal insulation properties were crucial
to the landing process. High-temperature insulation shield was composed of highresistance insulating materials. Heat insulation effects and mass reduction were
considered, and the mass was reduced as much as possible in the premise of heat insulation performance requirement satisfied when high-temperature insulation shield
was designed. When the 7500 N engine was firing, the high temperature of engine
nozzle was insulated from main body of the lunar lander. Only a small amount of
heat was introduced into the lunar lander through the high-temperature insulation
shield to ensure that the temperature of structure and instruments in modules would
not be higher than requirement.