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3 System Design of Lunar Lander
3.2 Principles of System Design
The majors involved in system design of lunar lander included theory and
methodology of system engineering, aerospace dynamics, engineering cybernetics,
propulsion, heat transfer theory, structure mechanics, computer science, mechanical
engineering, electronic engineering, microwave telecommunication, environment
engineering and etc. The basic principles should be followed to achieve a good lunar
lander as followings [1].
(1) Satisfying requirements of mission goals. According to the requirements of
mission goals, mission analysis should be conducted at first to determine
a set of quantitative functional specification by user’s requirements. Those
specifications could be transferred to detail specification of the design.
(2) Implementing system integrity. Lunar lander was a complex system which was
a functional unit made up of several components that interacted with and rely
on each other. Function and performance of each component should be studied.
Furthermore, the system function and properties of lunar lander as an integrated
system should be studied under interaction among all components in system
design. The system integrity should be considered when the subsystems were
designed. If there was incompatibility and contradiction among subsystems,
(3) Regarding system hierarchy. There should be a hierarchy system of all
elements in a system from simplicity to complexity and from low to high.
The engineering system of lunar lander included system, subsystem, equipment, assembly, component, parts and etc. in hierarchy. For the system design
of a lunar lander, requirements and validation should be analyzed from top to
bottom. Then it was validated to satisfy the requirements from bottom to top.
Finally the system was integrated.
(4) Pursuing optimization in system level. The optimization of system design of a
lunar lander should be done to determine the lander type, system specifications
and some partial specifications by digital models and comprehensive evaluation
with computer. It should be considered including orbital environment, performance, schedule, cost, risk, benefit and constraints such as launch vehicle
launch site, ground telecommunication station and ground application in the
system optimization. The optimization criteria might be the performance, or
lightest weight or lowest costs. The system design aimed at the optimization of
system performance, not optimization of some parts, assembly or subsystems.
(5) Adapting to specific environment. The specific environment for lunar lander
was different from satellites on Earth orbit and lunar orbiters including engine
plume, vibration, lunar dust during landing and lunar terrain, lunar regolith,
lunar low gravity, extreme high and low temperature. Those environmental
effects should be considered for solution during system design of lunar lander.
(6) Assuring accordance of engineering system. The engineering system for the
lunar soft landing mission included lunar lander, launch vehicle, launch site,
ground telecommunication station system and ground application system. The
accordance of lunar lander interface with other engineering system should be
ensured to achieve the successful landing.
3 System Design of Lunar Lander
3.2 Principles of System Design
The majors involved in system design of lunar lander included theory and
methodology of system engineering, aerospace dynamics, engineering cybernetics,
propulsion, heat transfer theory, structure mechanics, computer science, mechanical
engineering, electronic engineering, microwave telecommunication, environment
engineering and etc. The basic principles should be followed to achieve a good lunar
lander as followings [1].
(1) Satisfying requirements of mission goals. According to the requirements of
mission goals, mission analysis should be conducted at first to determine
a set of quantitative functional specification by user’s requirements. Those
specifications could be transferred to detail specification of the design.
(2) Implementing system integrity. Lunar lander was a complex system which was
a functional unit made up of several components that interacted with and rely
on each other. Function and performance of each component should be studied.
Furthermore, the system function and properties of lunar lander as an integrated
system should be studied under interaction among all components in system
design. The system integrity should be considered when the subsystems were
designed. If there was incompatibility and contradiction among subsystems,
(3) Regarding system hierarchy. There should be a hierarchy system of all
elements in a system from simplicity to complexity and from low to high.
The engineering system of lunar lander included system, subsystem, equipment, assembly, component, parts and etc. in hierarchy. For the system design
of a lunar lander, requirements and validation should be analyzed from top to
bottom. Then it was validated to satisfy the requirements from bottom to top.
Finally the system was integrated.
(4) Pursuing optimization in system level. The optimization of system design of a
lunar lander should be done to determine the lander type, system specifications
and some partial specifications by digital models and comprehensive evaluation
with computer. It should be considered including orbital environment, performance, schedule, cost, risk, benefit and constraints such as launch vehicle
launch site, ground telecommunication station and ground application in the
system optimization. The optimization criteria might be the performance, or
lightest weight or lowest costs. The system design aimed at the optimization of
system performance, not optimization of some parts, assembly or subsystems.
(5) Adapting to specific environment. The specific environment for lunar lander
was different from satellites on Earth orbit and lunar orbiters including engine
plume, vibration, lunar dust during landing and lunar terrain, lunar regolith,
lunar low gravity, extreme high and low temperature. Those environmental
effects should be considered for solution during system design of lunar lander.
(6) Assuring accordance of engineering system. The engineering system for the
lunar soft landing mission included lunar lander, launch vehicle, launch site,
ground telecommunication station system and ground application system. The
accordance of lunar lander interface with other engineering system should be
ensured to achieve the successful landing.