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3 System Design of Lunar Lander
was strong, the heat radiating surface should be orientated toward zenith. The
effects of the attitude on the heat radiation efficiency should be considered.
(5) Requirement for exploration on lunar surface. For the requirements of payloads
onboard lunar lander, lunar lander should satisfy requirements such as installation room, orientation, power supply, data transmission, temperature and
etc.
5. Analysis of survival on lunar night.
The rotation period of the Moon is about 27.3 days. The lunar daytime is about 14
Earth days while the lunar night is also 14 Earth days. There is no sun light and the
extreme temperature may be −180 °C on lunar night.
There were big differences for lunar lander on lunar night from spacecraft in
shadow of the Earth or the Moon, which are listed as following.
(1) Long duration. The lunar night is about 14 Earth days without sun light, which
is much longer than the time of shadow on the Earth or lunar orbit.
(2) Lack of space infrared radiation heat flux. For the spacecraft on Low Earth
Orbit, there is specific infrared radiation heat flux from the Earth in the shadow.
But such heat flux is little for the Moon because the lowest temperature of lunar
surface may be −180 °C on lunar night.
(3) Profound effects of lunar surface. The lunar terrain might be regarded as infinite
for lunar lander. There was not only heat radiation exchange but also irregular
conduction of heat because lunar lander touched lunar surface. Because the
temperature on lunar surface drops rapidly on lunar night, the temperature of
lunar lander was influenced profoundly.
Because of the special properties of surface environment on lunar night, the power
supply was the key of survival on lunar night for lunar lander. If energy storage
device such as battery was used to provide power and heat, the capacity should be
big enough. If lunar lander was designed to hibernate on lunar night, the requirement
for power supply could be reduced greatly because only storage temperature should
be maintained. But the autonomous wake up of lunar lander should be solved at the
same time. When the power supply of lunar lander was off, the criterion for waken
up may be illuminance of sun light and temperature, which means lunar lander was
awakened up autonomously when the illuminance of sun light and temperature on
lunar surface satisfied the requirements for operation after the dawn.
The instruments in lunar lander might be damaged or failure if there was no thermal
control on lunar night. So there must some kind of power source to ensure the safety
of lunar lander on lunar night that was adapted to lunar environment and able to work
without sun light and special thermal control. The radioisotope heat source was one of
nuclear energy, which was longevity, adaptable to environment, reliable, no external
energy required and capable of providing heat and power source simultaneously.
So Radioisotope Thermoelectric Generator (RTG) and heat unit could provide lunar
lander with heat and power energy under extreme environment to support survival
on lunar night.
3 System Design of Lunar Lander
was strong, the heat radiating surface should be orientated toward zenith. The
effects of the attitude on the heat radiation efficiency should be considered.
(5) Requirement for exploration on lunar surface. For the requirements of payloads
onboard lunar lander, lunar lander should satisfy requirements such as installation room, orientation, power supply, data transmission, temperature and
etc.
5. Analysis of survival on lunar night.
The rotation period of the Moon is about 27.3 days. The lunar daytime is about 14
Earth days while the lunar night is also 14 Earth days. There is no sun light and the
extreme temperature may be −180 °C on lunar night.
There were big differences for lunar lander on lunar night from spacecraft in
shadow of the Earth or the Moon, which are listed as following.
(1) Long duration. The lunar night is about 14 Earth days without sun light, which
is much longer than the time of shadow on the Earth or lunar orbit.
(2) Lack of space infrared radiation heat flux. For the spacecraft on Low Earth
Orbit, there is specific infrared radiation heat flux from the Earth in the shadow.
But such heat flux is little for the Moon because the lowest temperature of lunar
surface may be −180 °C on lunar night.
(3) Profound effects of lunar surface. The lunar terrain might be regarded as infinite
for lunar lander. There was not only heat radiation exchange but also irregular
conduction of heat because lunar lander touched lunar surface. Because the
temperature on lunar surface drops rapidly on lunar night, the temperature of
lunar lander was influenced profoundly.
Because of the special properties of surface environment on lunar night, the power
supply was the key of survival on lunar night for lunar lander. If energy storage
device such as battery was used to provide power and heat, the capacity should be
big enough. If lunar lander was designed to hibernate on lunar night, the requirement
for power supply could be reduced greatly because only storage temperature should
be maintained. But the autonomous wake up of lunar lander should be solved at the
same time. When the power supply of lunar lander was off, the criterion for waken
up may be illuminance of sun light and temperature, which means lunar lander was
awakened up autonomously when the illuminance of sun light and temperature on
lunar surface satisfied the requirements for operation after the dawn.
The instruments in lunar lander might be damaged or failure if there was no thermal
control on lunar night. So there must some kind of power source to ensure the safety
of lunar lander on lunar night that was adapted to lunar environment and able to work
without sun light and special thermal control. The radioisotope heat source was one of
nuclear energy, which was longevity, adaptable to environment, reliable, no external
energy required and capable of providing heat and power source simultaneously.
So Radioisotope Thermoelectric Generator (RTG) and heat unit could provide lunar
lander with heat and power energy under extreme environment to support survival
on lunar night.