Chapter 11
Landing Gear Technology of Lunar
Lander
11.1 Introduction
Lander cushion is one of key technologies in soft-landing on celestial bodies other
than Earth. It can attenuate the landing shock to acceptable level to ensure stable
landing of the lander and safety of onboard crews and devices by means of energy
transformation or dissipation.
During a typical soft-landing process, the lunar lander fired its retro-rocket engine
to decelerate at first. When the velocity relative to the landing surface was dozens
of meters per second or even more preferable several meters per second, the landing
impact energy would be absorbed by the landing gear to ensure safe landing. Up to
date, there were two types of landing cushion system in past lunar landing missions:
landing airbag [1] and landing gear. As for the airbag, impact energy was absorbed by
gas compression in the bag, gas venting from one chamber to another chamber, and
elastic-plastic deformation of airbag material [2]. For the landing with airbag, there
might be bouncing, rolling and turnover of the lunar lander during landing impact.
It was difficult to achieve high landing accuracy and predefined landing attitude.
Therefore the, airbag was preferred to the lander with higher landing velocity, but
light landing mass and small size, which would not return from the Moon. The landing
gear system absorbed the impact energy by the deformation of one or more struts in
the landing gear mechanism. With the landing gear system, it was easy to control the
attitude after landing and avoid bouncing during landing. The landing gear system
was more suitable to the lander with lower landing velocity, heavier landing mass and
large size, especially a strict attitude control requirement after landing. Meanwhile
with the support of landing gear system, the lander could serve as a launch platform
for lift-off on lunar surface. Therefore, the landing gear system was more suitable to
the landing and return mission. A typical landing gear system is shown in Fig. 11.1.
The crucial function of the landing gear was to ensure stable and safe landing, i.e.,
not only the lander would not turn over when landing but also the landing impact on
the structure was within the specific range. In practice, generally there were several
sets of landing gear, symmetrically installed on the bottom of the structure. The
© National Defense Industry Press and Springer Nature Singapore Pte Ltd. 2021
D.-Y. Yu et al., Technology of Lunar Soft Lander, Space Technology Library 38,
https://doi.org/10.1007/978-981-15-6580-9_11
367
Landing Gear Technology of Lunar
Lander
11.1 Introduction
Lander cushion is one of key technologies in soft-landing on celestial bodies other
than Earth. It can attenuate the landing shock to acceptable level to ensure stable
landing of the lander and safety of onboard crews and devices by means of energy
transformation or dissipation.
During a typical soft-landing process, the lunar lander fired its retro-rocket engine
to decelerate at first. When the velocity relative to the landing surface was dozens
of meters per second or even more preferable several meters per second, the landing
impact energy would be absorbed by the landing gear to ensure safe landing. Up to
date, there were two types of landing cushion system in past lunar landing missions:
landing airbag [1] and landing gear. As for the airbag, impact energy was absorbed by
gas compression in the bag, gas venting from one chamber to another chamber, and
elastic-plastic deformation of airbag material [2]. For the landing with airbag, there
might be bouncing, rolling and turnover of the lunar lander during landing impact.
It was difficult to achieve high landing accuracy and predefined landing attitude.
Therefore the, airbag was preferred to the lander with higher landing velocity, but
light landing mass and small size, which would not return from the Moon. The landing
gear system absorbed the impact energy by the deformation of one or more struts in
the landing gear mechanism. With the landing gear system, it was easy to control the
attitude after landing and avoid bouncing during landing. The landing gear system
was more suitable to the lander with lower landing velocity, heavier landing mass and
large size, especially a strict attitude control requirement after landing. Meanwhile
with the support of landing gear system, the lander could serve as a launch platform
for lift-off on lunar surface. Therefore, the landing gear system was more suitable to
the landing and return mission. A typical landing gear system is shown in Fig. 11.1.
The crucial function of the landing gear was to ensure stable and safe landing, i.e.,
not only the lander would not turn over when landing but also the landing impact on
the structure was within the specific range. In practice, generally there were several
sets of landing gear, symmetrically installed on the bottom of the structure. The
© National Defense Industry Press and Springer Nature Singapore Pte Ltd. 2021
D.-Y. Yu et al., Technology of Lunar Soft Lander, Space Technology Library 38,
https://doi.org/10.1007/978-981-15-6580-9_11
367