16.3 Requirements
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celestial body in blue magnitude. (3) About 550 nm. It is applied to measure yellow
and green composition of celestial body in apparent magnitude.
The main interference to observation is the stray light from the Sun. Therefore,
the control of stray light is a very important factor in lunar-based optical observation.
4. Shapes and Radiation of Earth Plasmasphere
The plasmasphere, or inner magnetosphere, is a region of the Earth’s magnetosphere.
It is located above the ionosphere. It consists of low energy plasma. The major
composition includes H, He and O. About 90% of its composition is H
+ and He
+ is
secondary. When the distance to Earth is further, the plasma density is decreasing.
When the plasma density is lower than one decimal, the boundary is called outer
boundary of plasmasphere, which is also known as the plasmapause. The biggest
radius of the plasmasphere is about 5 times of Earth radius.
The shape of Earth plasmasphere is affected by change of solar wind. When there
is solar flare, the shape of Earth plasmasphere will change greatly. The H
+ in Earth
plasmasphere doesn’t generate radiation. The main characteristic wavelength of He
+
is 30.4 nm. The radiation intensity of top plasmasphere is about 0.1 RayL (1RayL
= 1 Pa•s/m). The maximum radiation intensity of central region is about 10 RayL.
Generally, the change of Earth plasmasphere is observed by observing change of
radiation characteristic at 30.4 nm.
There are two kinds of background interference in adjacent He
+ characteristic
radiation wavelength. The one is 58.5 nm radiation generated by inner He atom at
the edge of Earth plasmasphere, which is below 2000 km altitude; the maximum
radiation intensity is about 700 RayL; the average radiation intensity is about 60
RayL. The other is 121.6 nm radiation generated between Earth plasmasphere and
interplanetary space, with radiation intensity at about 35000 RayL.
5. Lunar Dust
Lunar dust is the finest lunar soil grain with diameter less than 1 mm. Its electrical
conductivity is very low. So, it is easy to be charged in sunlight and maintain for a
long time. After charged by solar wind radiation, the lunar dust would float and move.
When the lunar day and lunar night is alternated, the lunar dust will be periodically
lifted because of charged effect by solar ultraviolet radiation. With landing impact
and engine firing of the lunar lander, movement of the lunar rover and impact of
small bodies on lunar surface, lunar dust will be activated. The charged lunar dust
may stick to any surface it comes in contact with.
527
celestial body in blue magnitude. (3) About 550 nm. It is applied to measure yellow
and green composition of celestial body in apparent magnitude.
The main interference to observation is the stray light from the Sun. Therefore,
the control of stray light is a very important factor in lunar-based optical observation.
4. Shapes and Radiation of Earth Plasmasphere
The plasmasphere, or inner magnetosphere, is a region of the Earth’s magnetosphere.
It is located above the ionosphere. It consists of low energy plasma. The major
composition includes H, He and O. About 90% of its composition is H
+ and He
+ is
secondary. When the distance to Earth is further, the plasma density is decreasing.
When the plasma density is lower than one decimal, the boundary is called outer
boundary of plasmasphere, which is also known as the plasmapause. The biggest
radius of the plasmasphere is about 5 times of Earth radius.
The shape of Earth plasmasphere is affected by change of solar wind. When there
is solar flare, the shape of Earth plasmasphere will change greatly. The H
+ in Earth
plasmasphere doesn’t generate radiation. The main characteristic wavelength of He
+
is 30.4 nm. The radiation intensity of top plasmasphere is about 0.1 RayL (1RayL
= 1 Pa•s/m). The maximum radiation intensity of central region is about 10 RayL.
Generally, the change of Earth plasmasphere is observed by observing change of
radiation characteristic at 30.4 nm.
There are two kinds of background interference in adjacent He
+ characteristic
radiation wavelength. The one is 58.5 nm radiation generated by inner He atom at
the edge of Earth plasmasphere, which is below 2000 km altitude; the maximum
radiation intensity is about 700 RayL; the average radiation intensity is about 60
RayL. The other is 121.6 nm radiation generated between Earth plasmasphere and
interplanetary space, with radiation intensity at about 35000 RayL.
5. Lunar Dust
Lunar dust is the finest lunar soil grain with diameter less than 1 mm. Its electrical
conductivity is very low. So, it is easy to be charged in sunlight and maintain for a
long time. After charged by solar wind radiation, the lunar dust would float and move.
When the lunar day and lunar night is alternated, the lunar dust will be periodically
lifted because of charged effect by solar ultraviolet radiation. With landing impact
and engine firing of the lunar lander, movement of the lunar rover and impact of
small bodies on lunar surface, lunar dust will be activated. The charged lunar dust
may stick to any surface it comes in contact with.