408
12 Integration and Assembly Technology of Lunar Lander
(2) There were a lot of sensors with high assembly accuracy. There were launch,
LTO, circumlunar orbit and powered descent in the flight profile of the Chang’E-3
lunar lander. The navigation and control of the lunar lander was crucial. In order to
ensure smooth and safe soft-landing, high-accurate sensors such as star sensor, solar
sensor, lunar terrain identification sensor, speedometer and ranging sensor, should
be configured. The accuracy of such sensors had important implications on orbit
control and obstacle avoidance for soft-landing of the lunar lander. There were 20
sensors on the Chang’E-3 lunar lander, for which there were special requirements,
such as stringent assembly accuracy requirements (for example, the assembly accuracy requirement of the speedometer antenna should be less than 12 arcseconds in
system assembly), as well as contamination protection for optical surfaces of sensors,
collision prevention for hardware, and transportation damping.
(3) There were many mechanisms with high assembly requirements and complex
verification. Besides conventional solar wing deployment mechanism as common
satellite, generally there were landing legs mechanisms. At the same time, for roving
on lunar surface and other scientific exploration requirements, there should be the
lunar rover release and transfer mechanism, pointing mechanism for cameras and
etc. The assembly quality of mechanism was directly related to the deployment and
movement performance of the mechanism, which was crucial for success of the lunar
lander. Meanwhile, for the newly developed mechanisms such as the landing gear
mechanism and the lunar rover transfer mechanism, it was necessary to conduct verification and test during AIT process, which led new challenges for system integration
and assembly.
(4) The high assembly risk of radioactive isotope equipment should be simulated
and verified. In order to ensure that the lunar lander could survive in −180°C of lunar
night, generally there should be multiple radioisotope equipment on the lunar lander,
including radioisotope heat unit for key instruments during lunar night and gamma
altimeter. There were four instruments with radioactive isotopes, which were installed
on the top plate, bottom plate, and lateral plates of the Chang’E-3 lunar lander.
These instruments with radioactive isotopes should be installed or assembled at the
launch tower. It was an inevitable issue to determine the assembly time, assembly
process, assembly reliability of these instruments and personnel operation safety
during assembly.
(5) The reliability requirement for assembly process was higher because the operation environment on lunar surface was harsh. Compared with general satellite, the
lunar lander should experience not only dynamic environment during launch and
space environment during flight, but also landing impact environment, high temperature during operation in lunar day and extremely low temperature during lunar night.
Therefore, during assembly process, the adaptability and reliability of the assembly
process under special environment for the lunar lander should be considered, such
as the elongation and shrinkage of the cable in high and extremely low temperature.
12 Integration and Assembly Technology of Lunar Lander
(2) There were a lot of sensors with high assembly accuracy. There were launch,
LTO, circumlunar orbit and powered descent in the flight profile of the Chang’E-3
lunar lander. The navigation and control of the lunar lander was crucial. In order to
ensure smooth and safe soft-landing, high-accurate sensors such as star sensor, solar
sensor, lunar terrain identification sensor, speedometer and ranging sensor, should
be configured. The accuracy of such sensors had important implications on orbit
control and obstacle avoidance for soft-landing of the lunar lander. There were 20
sensors on the Chang’E-3 lunar lander, for which there were special requirements,
such as stringent assembly accuracy requirements (for example, the assembly accuracy requirement of the speedometer antenna should be less than 12 arcseconds in
system assembly), as well as contamination protection for optical surfaces of sensors,
collision prevention for hardware, and transportation damping.
(3) There were many mechanisms with high assembly requirements and complex
verification. Besides conventional solar wing deployment mechanism as common
satellite, generally there were landing legs mechanisms. At the same time, for roving
on lunar surface and other scientific exploration requirements, there should be the
lunar rover release and transfer mechanism, pointing mechanism for cameras and
etc. The assembly quality of mechanism was directly related to the deployment and
movement performance of the mechanism, which was crucial for success of the lunar
lander. Meanwhile, for the newly developed mechanisms such as the landing gear
mechanism and the lunar rover transfer mechanism, it was necessary to conduct verification and test during AIT process, which led new challenges for system integration
and assembly.
(4) The high assembly risk of radioactive isotope equipment should be simulated
and verified. In order to ensure that the lunar lander could survive in −180°C of lunar
night, generally there should be multiple radioisotope equipment on the lunar lander,
including radioisotope heat unit for key instruments during lunar night and gamma
altimeter. There were four instruments with radioactive isotopes, which were installed
on the top plate, bottom plate, and lateral plates of the Chang’E-3 lunar lander.
These instruments with radioactive isotopes should be installed or assembled at the
launch tower. It was an inevitable issue to determine the assembly time, assembly
process, assembly reliability of these instruments and personnel operation safety
during assembly.
(5) The reliability requirement for assembly process was higher because the operation environment on lunar surface was harsh. Compared with general satellite, the
lunar lander should experience not only dynamic environment during launch and
space environment during flight, but also landing impact environment, high temperature during operation in lunar day and extremely low temperature during lunar night.
Therefore, during assembly process, the adaptability and reliability of the assembly
process under special environment for the lunar lander should be considered, such
as the elongation and shrinkage of the cable in high and extremely low temperature.