12.5 Typical Application of System Integration and Assembly
415
12.5 Typical Application of System Integration
and Assembly
The system integration and assembly runs through the AIT process of spacecraft.
The implementation sequence is based on the technical process of system integration and assembly. Generally, after the delivery of the main structure, the propulsion subsystem assembly, instrument assembly, cable assembly, thermal control unit
assembly, structural assembly and mechanism assembly will be implemented in
sequence. Then there will be operations related with various types of tests, such as
turning and attitude adjustment, hanging and transshipment and etc. At the end, the
spacecraft will be transported to the launch site for final assembly. As an example,
the application of typical system integration and assembly of the Chang’E-3 lunar
lander is described.
12.5.1 Propulsion Subsystem Assembly
Generally, the propulsion subsystem assembly was the first step of system integration
and assembly, including assembly of propulsion pipeline, gas tanks, propellant tanks,
engines and thrusters.
1. Manufacture and Assembly of Complex Pipeline
The pipeline of spacecraft is generally made of aluminum alloys, titanium alloys
and stainless-steel pipe. There are two manufacture methods. One is the traditional
manual method, characterized by a large burden, long cycle, low precision, and in
serial installation with spacecraft assembly. It is a mature method with less cost and
suitable for the development of single spacecraft pipeline manufacture. Another
method is to apply CAD/CAM technology to automatically bend the pipe. The
pipeline is designed in software and the data files that can be recognized by the
banding machine through interface software of numerical control bending machine
to implement CAD/CAM integration, which is characterized by high efficiency and
high accuracy. It can be implemented before assembly and in parallel with spacecraft
assembly. It is suitable for the manufacture of batches of pipeline of common spacecraft platforms. Before pipeline assembly, a series of examination and acceptance
shall be conducted. The pipeline shall be fixed by pipeline support. After completion of propulsion subsystem assembly, the propulsion pipeline shall be examined
by system leak test and single point leak test. The lunar lander was a single spacecraft. Therefore, the traditional manual method was applied to manufacture pipelines
with less cost and mature technology. The good result was achieved in the design,
manufacture and assembly of the pipeline in the Chang’E-3 lunar lander.
2. Assembly of Parallel Tanks on Cross Support Structure
The assembly method of tanks in the Chang’E-3 lunar lander was different from
other Chinese spacecraft. The traditional tank is assembled on the spacecraft bearing
415
12.5 Typical Application of System Integration
and Assembly
The system integration and assembly runs through the AIT process of spacecraft.
The implementation sequence is based on the technical process of system integration and assembly. Generally, after the delivery of the main structure, the propulsion subsystem assembly, instrument assembly, cable assembly, thermal control unit
assembly, structural assembly and mechanism assembly will be implemented in
sequence. Then there will be operations related with various types of tests, such as
turning and attitude adjustment, hanging and transshipment and etc. At the end, the
spacecraft will be transported to the launch site for final assembly. As an example,
the application of typical system integration and assembly of the Chang’E-3 lunar
lander is described.
12.5.1 Propulsion Subsystem Assembly
Generally, the propulsion subsystem assembly was the first step of system integration
and assembly, including assembly of propulsion pipeline, gas tanks, propellant tanks,
engines and thrusters.
1. Manufacture and Assembly of Complex Pipeline
The pipeline of spacecraft is generally made of aluminum alloys, titanium alloys
and stainless-steel pipe. There are two manufacture methods. One is the traditional
manual method, characterized by a large burden, long cycle, low precision, and in
serial installation with spacecraft assembly. It is a mature method with less cost and
suitable for the development of single spacecraft pipeline manufacture. Another
method is to apply CAD/CAM technology to automatically bend the pipe. The
pipeline is designed in software and the data files that can be recognized by the
banding machine through interface software of numerical control bending machine
to implement CAD/CAM integration, which is characterized by high efficiency and
high accuracy. It can be implemented before assembly and in parallel with spacecraft
assembly. It is suitable for the manufacture of batches of pipeline of common spacecraft platforms. Before pipeline assembly, a series of examination and acceptance
shall be conducted. The pipeline shall be fixed by pipeline support. After completion of propulsion subsystem assembly, the propulsion pipeline shall be examined
by system leak test and single point leak test. The lunar lander was a single spacecraft. Therefore, the traditional manual method was applied to manufacture pipelines
with less cost and mature technology. The good result was achieved in the design,
manufacture and assembly of the pipeline in the Chang’E-3 lunar lander.
2. Assembly of Parallel Tanks on Cross Support Structure
The assembly method of tanks in the Chang’E-3 lunar lander was different from
other Chinese spacecraft. The traditional tank is assembled on the spacecraft bearing