9.3 Analysis of Technical Characteristics
307
9.3.2 Constraints
Compared with past spacecraft, the most challenging requirement for OBDH
subsystem of the lunar lander was the design of miniaturized and highly integrated
electronic system. For example, the mass and power consumption constraints for
OBDH subsystem of the Chang’E-3 lunar lander were similar to the Chang’E-1
probe. But there were many new tasks and devices integrated, such as payload
management (including load bus controllers, multiplexing, and large-capacity
storage), power supply and distribution controllers, pyro device controllers, heating
loop controllers, solar panel mechanism controllers, directional antenna biaxial
mechanism controllers, lunar rover transfer mechanism controllers, camera pointing
mechanism controllers, –Y module cover mechanism controllers, and two-phase
fluid loop valve controllers. At the same time, the mass and power consumption were
strictly constrained, so it was very difficult to design a reliable OBDH sub system
with enough reliability. There the new integrated electronic technology should be
applied.
9.4 Design Methodology
9.4.1 Principles of Design
When the OBDH subsystem was designed, the modular design should be emphasized
to support an open system. By adding and removing modules to form a system
that adapted to different spacecraft flight missions, the reliability of the system was
improved by using the hardware and software modules verified by flight tests as much
as possible. The standardization of function and interface should be emphasized too.
The standardization of function could help to implement the integration of electronic
system. The standardization of the interface could greatly improve the standardization
level of design, matching and reliability of the interface, which could not only shorten
spacecraft development cycle and save cost, but also help to improve the versatility
of OBDH subsystem and its equipment so as to meet the needs of different space
missions and avoid duplication of development. There were following principles of
design.
(1) The system was a modular structure that allows the same basic module to
be used for a variety of spacecraft, which could achieve standardization of
subsystem structure, operating procedures and testing.
(2) The open system architecture was applied in both hardware and software with
standard interfaces, standard remote terminals and standard program to implement commands and data distribution function, and data acquisition function.
It could be used repeatedly in development and conducive to applying more
mature and even validated parts and software by flight validation.
307
9.3.2 Constraints
Compared with past spacecraft, the most challenging requirement for OBDH
subsystem of the lunar lander was the design of miniaturized and highly integrated
electronic system. For example, the mass and power consumption constraints for
OBDH subsystem of the Chang’E-3 lunar lander were similar to the Chang’E-1
probe. But there were many new tasks and devices integrated, such as payload
management (including load bus controllers, multiplexing, and large-capacity
storage), power supply and distribution controllers, pyro device controllers, heating
loop controllers, solar panel mechanism controllers, directional antenna biaxial
mechanism controllers, lunar rover transfer mechanism controllers, camera pointing
mechanism controllers, –Y module cover mechanism controllers, and two-phase
fluid loop valve controllers. At the same time, the mass and power consumption were
strictly constrained, so it was very difficult to design a reliable OBDH sub system
with enough reliability. There the new integrated electronic technology should be
applied.
9.4 Design Methodology
9.4.1 Principles of Design
When the OBDH subsystem was designed, the modular design should be emphasized
to support an open system. By adding and removing modules to form a system
that adapted to different spacecraft flight missions, the reliability of the system was
improved by using the hardware and software modules verified by flight tests as much
as possible. The standardization of function and interface should be emphasized too.
The standardization of function could help to implement the integration of electronic
system. The standardization of the interface could greatly improve the standardization
level of design, matching and reliability of the interface, which could not only shorten
spacecraft development cycle and save cost, but also help to improve the versatility
of OBDH subsystem and its equipment so as to meet the needs of different space
missions and avoid duplication of development. There were following principles of
design.
(1) The system was a modular structure that allows the same basic module to
be used for a variety of spacecraft, which could achieve standardization of
subsystem structure, operating procedures and testing.
(2) The open system architecture was applied in both hardware and software with
standard interfaces, standard remote terminals and standard program to implement commands and data distribution function, and data acquisition function.
It could be used repeatedly in development and conducive to applying more
mature and even validated parts and software by flight validation.