JPH0820399A - Three-axis geostationary satellite - Google Patents

Abstract

PURPOSE:To provide a three-axis geostationary satellite capable of sharply reducing the incoming heat by sunlight radiation while maintaining the heat radiation quantity by radiation, reducing the seasonal fluctuation of the heat radiation quantity from the satellite, increasing the heat radiation quantity, preventing the overheat of equipment, and capable of keeping the temperature of the equipment nearly constant. CONSTITUTION:This three-axis geostationary satellite is provided with a main body 14 having south-north plane panels 12 facing the direction of the south-north axis P and side face panels 13 surrounding the south-north axis and shielding panels 16 connected to the outer peripheries of the south-north plane panels 12 of the main body 14 at the inner ends 16a and extended outward in the south-north axis direction at the outer ends 16b. The outer ends 16b of the shielding panels 16 are positioned at the positions where the sunlight 4 does not directly enter the south-north plane panels 12 at the maximum incidence angle theta (23.5 deg.) to the south-north plane panels 12. Inner faces 16c of the shielding panels 16 are mirror finished surfaces having the same incidence angle and reflection angle of light, and the angle alpha of the shielding panels 16 against the south-north axis is set so that the sunlight reflected on the inner faces of the shielding panel 16 is not reflected to the south-north plane panels 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-axis geostationary satellite whose main body has three axes fixed in an inertial space.

[0002]

2. Description of the Related Art In order for a device mounted on an artificial satellite to operate as designed and to maintain a specified life,
It is necessary to control the operating environment temperature of the device within a certain range. The temperature of the satellite is determined by the balance between the heat input to the satellite and the heat output (heat dissipation) that goes out of the satellite. The heat input to the satellite includes radiant heat from sunlight and heat from the onboard equipment.

Among the artificial satellites, the geostationary satellite has a revolution period around the earth equal to the rotation period of the earth, and is relatively always located at the same place from the earth. Geostationary satellites include spin satellites whose main body spins and three-axis geostationary satellites whose three axes (P, Y, R in Fig. 5) are fixed in inertial space. On the other hand, it has the feature that it can always maintain the same orientation.

[0004]

As illustrated in FIG. 5, the 3-axis geostationary satellite 1 is always on the equatorial plane of the earth E, and the heat input to the north-south surface 2 by solar radiation does not change daily. Only seasonal changes. The maximum incident angle of the sunlight 4 on the north-south surface is the angle θ of the earth axis with respect to the orbital surface (θ = 23.5 °).
Therefore, the heat input to the north-south surface is smaller than the heat input to the side surface 3 due to solar radiation. For this reason, in the conventional three-axis geostationary satellite, the side surfaces are generally insulated, and the north and south surfaces are used as the heat dissipation surface.

The panel of the north-south surface 2 of the three-axis geostationary satellite has the maximum temperature of the south-surface panel at the winter solstice and the maximum temperature of the north-surface panel at the summer solstice. Especially in the winter solstice, the distance from the sun is the shortest, and the situation is the severest in terms of heat. in this case,
Heat generated from the equipment and heat input from sunlight are added to the south surface, and part of it is radiated to outer space by radiation, and the rest is radiated to space from the north surface, which is not exposed to the sun.

The heat balance equation on the north-south surface 2 is as follows:
QS ≈ εAσTS ⁴ (formula), North surface: QN ≈ εAσTN
⁴ (Equation), QS: Heat value of onboard equipment that radiates heat from the south surface, QN: Heat value of onboard equipment that radiates heat from the north surface, TS: absolute temperature of the south surface, TN: absolute temperature of the north surface,
ε: emissivity of north-south surface, a: solar absorption rate of north-south surface, A:
Area of north-south surface, S: solar heat input σ: Stefan Boltzmann constant.

However, in the conventional three-axis geostationary satellite, as is clear from the equation, the heat input (aS
Since there is A) and this heat input varies with the seasons, it is difficult to design the heat of the satellite, and the temperature of the equipment cannot be kept constant. There were problems such as overheating.

The present invention was devised to solve such problems. That is, the object of the present invention is to significantly reduce the heat input due to solar radiation while maintaining the heat radiation amount due to the radiation, thereby reducing the seasonal variation of the heat radiation amount from the satellite and reducing the heat radiation amount. It is an object of the present invention to provide a three-axis geostationary satellite capable of increasing the temperature of the device, preventing the device from overheating, and keeping the device temperature substantially constant.

[0009]

According to the present invention, the orbital period located above the equator and traveling around the earth is equal to the rotation period of the earth, the north-south axis parallel to the earth axis, the radial axis of the orbit, and the circumferential direction. A three-axis geostationary satellite having three axes, the three axes being fixed relative to the earth, and a main body having a north-south panel facing the north-south axis and a side panel enclosing the north-south axis, It is equipped with a light-shielding panel whose inner end is connected to the outer periphery of the north-south panel of the main body and whose outer end extends outward in the north-south axial direction. The light-shielding panel is positioned at a position where it does not directly enter the surface panel, the inner surface of the light-shielding panel is a mirror surface with the same incident angle of light and the reflection angle, and the angle with respect to the north-south axis of the light-shielding panel is
There is provided a three-axis geostationary satellite characterized in that the sunlight reflected on the inner surface of the light-shielding panel is set so as not to be reflected on the north-south surface panel.

According to a preferred embodiment of the present invention, the angle α of the shading panel with respect to the north-south axis is at least 23.5 ° or more, and for the maximum width L0 of the north-south panel, the inner edge to the outer edge of the light-shielding panel. The length L up to is at least L0
sin 23.5 ° / cos (α + 23.5 °) or more. Further, the main body is a box-shaped body composed of a rectangular north-south panel and a rectangular side panel, and the light-shielding panel is rotatably attached to each side of the north-south panel so that it can be folded inward. Furthermore, it is preferable that the light-shielding panel is a honeycomb sandwich panel having low heat conductivity.

[0011]

According to the above-mentioned structure of the present invention, a light-shielding panel having an inner end connected to the outer periphery of the north-south surface panel of the main body and an outer end extending outward in the north-south axial direction, the outer end of which extends to the north-south surface panel. Since the sunlight at the maximum incident angle is positioned so as not to directly enter the north-south panel, the light-shielding panel can block the direct incidence of the sunlight on the north-south panel. In addition, the inner surface of the light-shielding panel is a mirror surface with the same incident angle of light and the reflection angle, and the angle with respect to the north-south axis of the light-shielding panel is set so that the sunlight reflected on the inner surface of the light-shielding panel does not reflect to the north-south surface panel. Since it is set to, reflected light does not enter the north-south panel. Furthermore, since the inner surface of the shading panel is a mirror surface and has an angle inclined outward, part of the heat radiated from the north-south surface panel can be reflected on the inner surface of the shading panel and radiated to the true universe. The light-shielding panel does not hinder the heat radiation by radiation.

Therefore, while maintaining the amount of heat released by radiation,
The heat input due to solar radiation can be significantly reduced, which reduces the seasonal fluctuation of the heat radiation from the satellite, increases the heat radiation, prevents the equipment from overheating, and keeps the equipment temperature almost constant. Can be held at.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. In addition, the common part in each figure,
The same reference numbers are used. FIG. 1 is an overall perspective view of a 3-axis geostationary satellite according to the present invention, and FIG. 2 is a sectional view taken along the PY plane of FIG. The 3-axis geostationary satellite of the present invention is similar to FIG.
It is a geostationary satellite that is located above the equator and moves around the earth E and has a revolution period equal to the rotation period of the earth.
It has three axes, a north-south axis P parallel to the earth axis, a radial axis Y of the orbit, and a circumferential axis R, and these three axes P, Y, and R are fixed relative to the earth.

1 and 2, a three-axis geostationary satellite 10 of the present invention has a north-south panel 12 facing in the north-south axis P direction.
And a body 14 having a side panel 13 enclosing the north-south axis P
And an inner end 16a is connected to the outer periphery of the north-south panel 12 of the main body, and an outer end 16b extends outward in the north-south axial direction.
6 is provided. In the embodiment shown in FIGS. 1 and 2, the main body 14 is a box-shaped body including a rectangular north-south panel 12 and a rectangular side panel 13. In addition, the light shielding panel 16 is
It is rotatably attached to each side of the north-south panel 12 so that it can be folded inward.

FIG. 4 is a diagram showing the folding structure of the light shielding panel 16. As shown in this figure, the light-shielding panel has 12 of a to l.
It can be folded from the expanded state of (A) to the stored state of (B) by folding in the order of a to h, i, k, j, l. The opposite is true when deploying. With this configuration, the storage efficiency of the rocket fairing can be improved.

The light-shielding panel 16 is composed of a honeycomb sandwich panel having a small heat conductivity. Furthermore, the inner surface of the light-shielding panel 16 is a mirror surface having the same incident angle and reflected angle of light. The outer surface of the light-shielding panel 16 has the same mirror surface as the inner surface, or a multilayer heat insulating material (eg, ML) having high heat insulating performance.
I: Multi Layer Insulation) is provided. With such a configuration, heat input from the sunlight 4 to the light shielding panel 16 and heat transfer of the heat input to the main body 14 can be significantly reduced.

FIG. 3 is a diagram showing the positional relationship between the north-south panel 12 and the light-shielding panel 16 in FIG. 1 to 3, the outer end 16b of the shading panel 16 is positioned at a position where the sunlight 4 at the maximum incident angle θ (θ = 23.5 °) to the north-south panel 12 does not directly enter the north-south panel 12. Has been done. That is, in FIG. 3, when the angle of the shading panel with respect to the north-south axis is α and the maximum width of the north-south panel (line segment AB in the figure) is L0, the length from the inner end 16a to the outer end 16b of the shading panel 16 L is at least L
The angle α of the light-shielding panel and the length L of the light-shielding panel are set so as to be 0 · sin 23.5 ° / cos (α + 23.5 °) or more. In the triangle ABC and the perpendicular line BD to the line segment AC in FIG. 3, the length of the line segment BD is L0.sin.
It can be represented by θ and L · cos (α + θ).
Therefore, the length L from the inner end 16a to the outer end 16b of the light shielding panel 16 is at least L0.sin23.5 ° / co.
By setting s (α + 23.5 °) or more, the direct incidence of the sunlight 4 on the north-south surface panel 12 can be completely shielded by the light-shielding panel 16.

Further, in FIGS. 1 to 3, the light shielding panel 1
The inner surface 16c of 6 is a mirror surface having the same incident angle and reflection angle of light. In addition, the angle α of the shading panel 16 with respect to the north-south axis
Is set so that the sunlight 4 reflected on the inner surface 16c of the light shielding panel does not reflect to the north-south surface panel 12. That is, in FIG. 3, the angle α of the shading panel 16 with respect to the north-south axis P is at least the maximum incident angle (θ = 2) of the sunlight 4.
3.5 °) or more. With this configuration,
The sunlight 4 reflected by the inner surface 16c of the light shielding panel 16 is reflected to the outside (true universe side), and the reflected light does not enter the north-south surface panel. Similarly, since the inner surface 16c of the light-shielding panel is a mirror surface and has an angle α inclined outward, a part of the heat radiated from the north-south surface panel 12 is partially shielded.
The light can be reflected by the inner surface 16c of the and can be radiated to the true universe, and the heat radiation by radiation is not obstructed by the light shielding panel.

Therefore, with the above-mentioned configuration, the heat input due to the solar radiation can be greatly reduced while maintaining the heat radiation amount due to the radiation, thereby reducing the seasonal variation of the heat radiation amount from the satellite and releasing it. It is possible to increase the amount of heat, prevent the device from overheating, and keep the device temperature substantially constant. It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0020]

As described above, according to the three-axis geostationary satellite of the present invention, the direct incidence of sunlight on the north-south surface panel can be blocked by the light-shielding panel, and the sun on the inner surface of the light-shielding panel can be shielded. The reflected light does not enter the north-south panel. Furthermore, since the inner surface of the shading panel is a mirror surface and has an angle inclined outward, part of the heat radiated from the north-south surface panel can be reflected on the inner surface of the shading panel and radiated to the true universe. The light-shielding panel does not hinder the heat radiation by radiation.

Therefore, the three-axis geostationary satellite of the present invention can greatly reduce the heat input due to the solar radiation while maintaining the heat radiation due to the radiation, and thus the seasonal variation of the heat radiation from the satellite. It has excellent effects such as reduction, increase of heat radiation amount, prevention of overheating of equipment, and keeping equipment temperature almost constant.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a 3-axis geostationary satellite according to the present invention.

FIG. 2 is a cross-sectional view taken along the PY plane of FIG.

FIG. 3 is a positional relationship diagram between a north-south surface panel and a light-shielding panel in FIG.

FIG. 4 is a view showing a folding structure of a light shielding panel.

FIG. 5 is a positional relationship diagram of a conventional 3-axis geostationary satellite.

[Explanation of symbols]

 1 3-axis geostationary satellite 2 north-south surface 3 side surface 4 solar light 10 3-axis geostationary satellite 12 south-south surface panel 13 side panel 14 main body 16 light-shielding panel 16a inner edge 16b outer edge θ maximum incident angle of sunlight on north-south surface panel α light-shielding Angle of panel with respect to north-south axis P North-south axis Y Radial axis R Circumferential axis

Claims (4)

[Claims] 1. An orbit around the earth, which is located above the equator, has a revolution period equal to the rotation period of the earth, and has three axes of a north-south axis parallel to the earth axis, a radial axis of an orbit, and a circumferential axis. In a three-axis geostationary satellite whose axis is fixed relative to the earth, a main body having a north-south panel facing the north-south axis and side panels enclosing the north-south axis, and an inner periphery of the north-south panel of the main body. Equipped with a light-shielding panel whose ends are connected and the outer end extends outward in the north-south axial direction.The outer end of the light-shielding panel is positioned at a position where sunlight at the maximum incidence angle on the north-south panel does not directly enter the north-south panel. The inner surface of the light-shielding panel is a mirror surface where the incident angle of light is equal to the reflection angle, and the angle with respect to the north-south axis of the light-shielding panel is such that the sunlight reflected on the inner surface of the light-shielding panel does not reflect to the north-south surface panel. Is set to A 3-axis geostationary satellite. 2. The angle α of the light-shielding panel with respect to the north-south axis is at least 23.5 ° or more, and the length L from the inner edge to the outer edge of the light-shielding panel with respect to the maximum width L0 of the north-south surface panel.
Is at least L0 · sin23.5 ° / cos (α +
2. The three-axis geostationary satellite according to claim 1, wherein the three-axis geostationary satellite is at least 23.5 °. 3. The main body is a box-shaped body composed of a rectangular north-south panel and a rectangular side panel, and the light-shielding panel is rotatably attached to each side of the north-south panel so that it can be folded inward. The three-axis geostationary satellite according to claim 1, wherein 4. The triaxial geostationary satellite according to claim 1, wherein the light-shielding panel is formed of a honeycomb sandwich panel having low heat conductivity.