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11 Landing Gear Technology of Lunar Lander
(2) It could effectively absorb the impact load during landing. In the landing
process, the maximum impact load on the lunar lander should be limited in
specific range to ensure the safety of onboard instruments.
(3) It could ensure landing stability. Under complex landing conditions, the landing
gear mechanism could prevent the lunar lander from turning over to ensure
landing stability.
(4) It could provide effective long-term support for the lunar lander. After landing,
the landing gear mechanism should provide effective long-term support for the
lunar lander with required attitude. Sometimes it was also employed as a stable
launch platform for lift-off of sample return mission.
(5) Other functions. For example, the landing gear mechanism should give an
indicating signal when the footpad touches lunar surface to judge whether the
lunar lander was touched down.
In order to meet above function requirements, generally there were following
components in the landing gear mechanism.
(1) Primary strut. It was to absorb the vertical impact load and support the lunar
gravity of the lunar lander on lunar surface.
(2) Secondary struts. It was to absorb the horizontal impact load and help to support
the lunar gravity.
(3) Footpad. It was to prevent excessive penetration due to exceeding impact load.
Meanwhile, it was benefit to horizontal slide of the lunar lander if lunar terrain
was right. If the footpad impacted on an obstacle and horizontal impact load
was high enough while sliding on lunar surface, peripheral part of the footpad
could plastically deform to absorb part of energy.
(4) Hold-down and Release assembly. It was to hold down the landing gear
mechanism during launch and release it after orbit injection.
(5) Deployment and lock-up assembly. It was to deploy and lock up of the landing
gear mechanism after it was released.
(6) Lunar surface sensing probe. It was installed in the footpad or other part of the
landing gear mechanism and could output a triggering signal when the footpad
touched lunar surface.
2. Analysis of Initial Design Conditions
The initial design conditions of landing gear mechanism generally included the
following aspects.
(1) Mass properties of the lunar lander. It was the input for analysis and evaluation
of cushion performance and touchdown stability including mass, position of
the center of mass and moment of inertia in three directions.
(2) Touchdown velocity. The velocity was generally presented in local coordination system of the Moon, including the vertical and horizontal components. Together with total touchdown mass, it determined impact energy to
be absorbed by the landing gear mechanism.
11 Landing Gear Technology of Lunar Lander
(2) It could effectively absorb the impact load during landing. In the landing
process, the maximum impact load on the lunar lander should be limited in
specific range to ensure the safety of onboard instruments.
(3) It could ensure landing stability. Under complex landing conditions, the landing
gear mechanism could prevent the lunar lander from turning over to ensure
landing stability.
(4) It could provide effective long-term support for the lunar lander. After landing,
the landing gear mechanism should provide effective long-term support for the
lunar lander with required attitude. Sometimes it was also employed as a stable
launch platform for lift-off of sample return mission.
(5) Other functions. For example, the landing gear mechanism should give an
indicating signal when the footpad touches lunar surface to judge whether the
lunar lander was touched down.
In order to meet above function requirements, generally there were following
components in the landing gear mechanism.
(1) Primary strut. It was to absorb the vertical impact load and support the lunar
gravity of the lunar lander on lunar surface.
(2) Secondary struts. It was to absorb the horizontal impact load and help to support
the lunar gravity.
(3) Footpad. It was to prevent excessive penetration due to exceeding impact load.
Meanwhile, it was benefit to horizontal slide of the lunar lander if lunar terrain
was right. If the footpad impacted on an obstacle and horizontal impact load
was high enough while sliding on lunar surface, peripheral part of the footpad
could plastically deform to absorb part of energy.
(4) Hold-down and Release assembly. It was to hold down the landing gear
mechanism during launch and release it after orbit injection.
(5) Deployment and lock-up assembly. It was to deploy and lock up of the landing
gear mechanism after it was released.
(6) Lunar surface sensing probe. It was installed in the footpad or other part of the
landing gear mechanism and could output a triggering signal when the footpad
touched lunar surface.
2. Analysis of Initial Design Conditions
The initial design conditions of landing gear mechanism generally included the
following aspects.
(1) Mass properties of the lunar lander. It was the input for analysis and evaluation
of cushion performance and touchdown stability including mass, position of
the center of mass and moment of inertia in three directions.
(2) Touchdown velocity. The velocity was generally presented in local coordination system of the Moon, including the vertical and horizontal components. Together with total touchdown mass, it determined impact energy to
be absorbed by the landing gear mechanism.