84
3 System Design of Lunar Lander
time, as the lateral surface of cross strut plate could bear load, the requirement
of force transfer of landing cushion was satisfied.
(2) Centrosymmetric and paralleled installation of propellant tanks. Four quadrants provided by cross strut central module were used for installation of four
propellant tanks in centrosymmetry and parallel. The bottom flanges of propellant tanks were connected with interface ring directly and the top flanges of
propellant tanks were connected with cross strut plates by rods. Such design
would provide good vibration environment for propellant tanks because the
vibration load of the launch vehicle was transferred to propellant tanks by
interface ring directly. The height of mass center of central module is lower as
well as the height of mass center of the whole lunar lander. The mass center
of lunar lander would keep in line with the vertical axis when the mass of
propellant was changing.
(3) Connection between landing cushion mechanism with cross strut plates. When
landing cushion mechanism touched lunar surface, the impact load upon
landing cushion mechanism would act on lunar lander. Therefore reliability
and strength of the connection between landing cushion mechanism and lunar
lander should be ensured. The force transfer could be ensured when the four
landing legs were connected to cross strut plates by triangle plates in centrosymmetry. The large span of landing cushion mechanism after deployed was helpful
to increase landing stability.
(4) Configuration of equipments in different modules. There were two types of
instruments aboard lunar lander: one need survive through lunar night and
another one need not. Instruments of GNC and propulsion subsystems would
not work on lunar surface after safe landing, therefore it was unnecessary to
provide appropriate temperature. On the other hand, equipments of OBDH,
TT&C, power supply and payload subsystem would work for a long term on
lunar surface, therefore appropriate temperature should be maintained in lunar
daytime and night. Different modules for different equipments were designed
according to above characteristics then. There were two modules: +Y and −
Y modules for equipments which should survive through lunar night, where
RHU provided heat in lunar night. There were −Z and central modules for
equipments which should not survive through lunar night. Such design could
effectively save heat requirements in lunar night, which was good for design
of thermal control.
(5) Solar panels on top and radiators in different modules. The solar panels were
installed on top of lunar lander for repeated folding and unfolding as well as
hold-down before soft landing. The −Z module radiator was on the lateral in
which instruments should not survive through lunar night. The radiators of +Y
and −Y modules were on the top regarding the characteristic of lunar external
heat flux. The radiators were designed to tilt to adapt to tilt of lunar lander after
landing.
3 System Design of Lunar Lander
time, as the lateral surface of cross strut plate could bear load, the requirement
of force transfer of landing cushion was satisfied.
(2) Centrosymmetric and paralleled installation of propellant tanks. Four quadrants provided by cross strut central module were used for installation of four
propellant tanks in centrosymmetry and parallel. The bottom flanges of propellant tanks were connected with interface ring directly and the top flanges of
propellant tanks were connected with cross strut plates by rods. Such design
would provide good vibration environment for propellant tanks because the
vibration load of the launch vehicle was transferred to propellant tanks by
interface ring directly. The height of mass center of central module is lower as
well as the height of mass center of the whole lunar lander. The mass center
of lunar lander would keep in line with the vertical axis when the mass of
propellant was changing.
(3) Connection between landing cushion mechanism with cross strut plates. When
landing cushion mechanism touched lunar surface, the impact load upon
landing cushion mechanism would act on lunar lander. Therefore reliability
and strength of the connection between landing cushion mechanism and lunar
lander should be ensured. The force transfer could be ensured when the four
landing legs were connected to cross strut plates by triangle plates in centrosymmetry. The large span of landing cushion mechanism after deployed was helpful
to increase landing stability.
(4) Configuration of equipments in different modules. There were two types of
instruments aboard lunar lander: one need survive through lunar night and
another one need not. Instruments of GNC and propulsion subsystems would
not work on lunar surface after safe landing, therefore it was unnecessary to
provide appropriate temperature. On the other hand, equipments of OBDH,
TT&C, power supply and payload subsystem would work for a long term on
lunar surface, therefore appropriate temperature should be maintained in lunar
daytime and night. Different modules for different equipments were designed
according to above characteristics then. There were two modules: +Y and −
Y modules for equipments which should survive through lunar night, where
RHU provided heat in lunar night. There were −Z and central modules for
equipments which should not survive through lunar night. Such design could
effectively save heat requirements in lunar night, which was good for design
of thermal control.
(5) Solar panels on top and radiators in different modules. The solar panels were
installed on top of lunar lander for repeated folding and unfolding as well as
hold-down before soft landing. The −Z module radiator was on the lateral in
which instruments should not survive through lunar night. The radiators of +Y
and −Y modules were on the top regarding the characteristic of lunar external
heat flux. The radiators were designed to tilt to adapt to tilt of lunar lander after
landing.