4.4 Mechanism Design and Verification of Lunar Lander
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panels from being damaged due to overload in the process of orbit maneuver,
the solar panels should be folded before orbit maneuver and unfolded after
orbit maneuver. In addition, there was a large landing impact load during softlanding. Therefore, the solar panels should be folded before landing and, if
necessary, auxiliary held was also required. After successful landing, the solar
panels were deployed again and oriented to the Sun.
(4) Oriented to the sun. In order to meet power supply requirement of the lunar
lander, the solar panel mechanism should drive solar panels to be oriented to
the Sun and be able to maintain its position. In addition, the orientation to the
Sun should meet certain requirements of angle accuracy.
(5) Fundamental frequency requirement. The solar panels should meet certain
fundamental frequency requirements in the folded and unfolded state.
(6) Life requirement. The solar panels of the lunar lander should be folded and
unfolded repeatedly during the mission. Therefore, there are certain requirements for the operation times of the solar panel mechanism, i.e., the working
life requirements.
(7) Reliability requirement. The reliability of solar panel mechanism had a direct
impact on the power supply of solar panels. Therefore, the solar panel
mechanism should be highly reliable.
(8) Other functional requirements. After the solar panel mechanism was unfolded
or folded to designated position, an accurate signal or angle information should
be given to judge whether the solar panel mechanism is in position.
The requirements of the solar panel mechanism are listed in Table 4.3.
2. Task Analysis
The task analysis of flight hardware on spacecraft should be done according to
different mission profiles. All flight events, environmental conditions, and operating
conditions during flight operation should be defined to provide comprehensive and
correct inputs for design.
All matters during flight operation should be analyzed in task analysis to identify
critical environmental factors that affected the function, performance and reliability
of the flight hardware and made them quantization. The main contents of task analysis
included:
(1) Analysis of operation conditions combined with space environment and operation mode of flight hardware itself to identify all operation conditions and
determine the worst case of all operation conditions.
(2) Analysis of key failure modes that affected the function implementation of
flight hardware and might cause mission failure to identify key failure modes
and acceptable degradation modes, as well as establish criteria for task success.
Compared with solar panels of other spacecraft, the solar panels of the lunar lander
had a complex mission profile and tough working environment. Therefore, it was
particularly important to analyze tasks of solar panels of the lunar lander for all
mission profiles. As an example, the task analysis of the solar panels is given as
follows for the Chang’E-3 lunar lander:
125
panels from being damaged due to overload in the process of orbit maneuver,
the solar panels should be folded before orbit maneuver and unfolded after
orbit maneuver. In addition, there was a large landing impact load during softlanding. Therefore, the solar panels should be folded before landing and, if
necessary, auxiliary held was also required. After successful landing, the solar
panels were deployed again and oriented to the Sun.
(4) Oriented to the sun. In order to meet power supply requirement of the lunar
lander, the solar panel mechanism should drive solar panels to be oriented to
the Sun and be able to maintain its position. In addition, the orientation to the
Sun should meet certain requirements of angle accuracy.
(5) Fundamental frequency requirement. The solar panels should meet certain
fundamental frequency requirements in the folded and unfolded state.
(6) Life requirement. The solar panels of the lunar lander should be folded and
unfolded repeatedly during the mission. Therefore, there are certain requirements for the operation times of the solar panel mechanism, i.e., the working
life requirements.
(7) Reliability requirement. The reliability of solar panel mechanism had a direct
impact on the power supply of solar panels. Therefore, the solar panel
mechanism should be highly reliable.
(8) Other functional requirements. After the solar panel mechanism was unfolded
or folded to designated position, an accurate signal or angle information should
be given to judge whether the solar panel mechanism is in position.
The requirements of the solar panel mechanism are listed in Table 4.3.
2. Task Analysis
The task analysis of flight hardware on spacecraft should be done according to
different mission profiles. All flight events, environmental conditions, and operating
conditions during flight operation should be defined to provide comprehensive and
correct inputs for design.
All matters during flight operation should be analyzed in task analysis to identify
critical environmental factors that affected the function, performance and reliability
of the flight hardware and made them quantization. The main contents of task analysis
included:
(1) Analysis of operation conditions combined with space environment and operation mode of flight hardware itself to identify all operation conditions and
determine the worst case of all operation conditions.
(2) Analysis of key failure modes that affected the function implementation of
flight hardware and might cause mission failure to identify key failure modes
and acceptable degradation modes, as well as establish criteria for task success.
Compared with solar panels of other spacecraft, the solar panels of the lunar lander
had a complex mission profile and tough working environment. Therefore, it was
particularly important to analyze tasks of solar panels of the lunar lander for all
mission profiles. As an example, the task analysis of the solar panels is given as
follows for the Chang’E-3 lunar lander: