54
3 System Design of Lunar Lander
identify lunar terrain and avoid obstacles could help to make sure lunar lander
not to turn over and sink after landing because of the complexity of lunar
terrain.
(3) Cushion of landing impact. There would be large impact load when lunar
lander finally touches lunar surface. The landing cushion subsystem should
be designed to absorb the impact load to make sure lunar lander not to turn
over and sink at a predefined range of attitude and provide solid support for
operation on lunar surface after landing.
(4) Thermal control and power supply for survival on lunar surface. The illumination condition and external heat flux changed greatly from lunar daytime
to lunar night on lunar surface. It was a challenge to scatter heat under high
temperature during lunar day. It was also a challenge to provide enough power
supply and control the temperature without sun light during lunar night lasting
for 14 days.
(5) Ground simulation test for lunar environment. It was different in gravity,
temperature, illumination, radiation condition on lunar surface from Earth
orbit. So the theory and methodology for ground test should be studied, as
well as ground facilities and simulation equipments should be constructed to
make sure the sufficiency of ground test and validation.
3.3.2 Analysis of Landing Site
The landing site of lunar lander should be determined at first for the system design.
The difference between the landing sites had essential effects on the system design
of trajectory, telecommunication and configuration for lunar lander.
The basic principles for landing site selection were both engineering implementability and satisfying requirements of scientific exploration on the basis of safe
landing.
1. Engineering requirements
The implementability of engineering of landing site selection included lunar terrain,
access of trajectory, telecommunication condition of powered descent and operation
on lunar surface, sun light condition, thermal environment and etc. Effects on the
system design of lunar lander included by those factors as following:
(1) Lunar terrain. There are almost craters and rock everywhere on lunar surface.
It is relative smooth on the mare, while it is rugged on the highland. The lunar
terrain properties including slopes, pits and shape of rock were important to
safe landing and stable attitude after landing of lunar lander.
(2) Access of trajectory. The latitude of landing site should be less than the orbit
inclination of lunar lander before landing. Theoretically if the orbit was polar
orbit, lunar lander could be landed at any place on the Moon. But the repeat
period and telecommunication condition for specific landing site should be
considered at the same time. So the access of trajectory should be studied.
3 System Design of Lunar Lander
identify lunar terrain and avoid obstacles could help to make sure lunar lander
not to turn over and sink after landing because of the complexity of lunar
terrain.
(3) Cushion of landing impact. There would be large impact load when lunar
lander finally touches lunar surface. The landing cushion subsystem should
be designed to absorb the impact load to make sure lunar lander not to turn
over and sink at a predefined range of attitude and provide solid support for
operation on lunar surface after landing.
(4) Thermal control and power supply for survival on lunar surface. The illumination condition and external heat flux changed greatly from lunar daytime
to lunar night on lunar surface. It was a challenge to scatter heat under high
temperature during lunar day. It was also a challenge to provide enough power
supply and control the temperature without sun light during lunar night lasting
for 14 days.
(5) Ground simulation test for lunar environment. It was different in gravity,
temperature, illumination, radiation condition on lunar surface from Earth
orbit. So the theory and methodology for ground test should be studied, as
well as ground facilities and simulation equipments should be constructed to
make sure the sufficiency of ground test and validation.
3.3.2 Analysis of Landing Site
The landing site of lunar lander should be determined at first for the system design.
The difference between the landing sites had essential effects on the system design
of trajectory, telecommunication and configuration for lunar lander.
The basic principles for landing site selection were both engineering implementability and satisfying requirements of scientific exploration on the basis of safe
landing.
1. Engineering requirements
The implementability of engineering of landing site selection included lunar terrain,
access of trajectory, telecommunication condition of powered descent and operation
on lunar surface, sun light condition, thermal environment and etc. Effects on the
system design of lunar lander included by those factors as following:
(1) Lunar terrain. There are almost craters and rock everywhere on lunar surface.
It is relative smooth on the mare, while it is rugged on the highland. The lunar
terrain properties including slopes, pits and shape of rock were important to
safe landing and stable attitude after landing of lunar lander.
(2) Access of trajectory. The latitude of landing site should be less than the orbit
inclination of lunar lander before landing. Theoretically if the orbit was polar
orbit, lunar lander could be landed at any place on the Moon. But the repeat
period and telecommunication condition for specific landing site should be
considered at the same time. So the access of trajectory should be studied.