IP Library › Granted Patent US 11,420,774
Granted Patent B2
US 11,420,774 · App. 16/332,288 · Granted Aug 23, 2022

Pointing mechanism

Inventor: Shunichi Kawamura (Chiyoda-ku, JP)
Assignee: Mitsubishi Electric Corporation
B64G1/24B64G1/10B64G1/222B64G1/242B64G1/409
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Quick Facts
Patent No.
US 11,420,774
App. No.
16/332,288
Granted
Aug 23, 2022
Kind
B2
Abstract

An artificial satellite includes two pointing mechanisms. The pointing mechanisms respectively include main body side gimbals, deployed booms, thruster side gimbals, and thruster groups. The main body side gimbal connects the deployed boom to a satellite main body and adjusts a direction of the deployed boom. The thruster side gimbal connects the thruster to the deployed boom and adjusts the direction of the thruster. Each gimbal is a two-axis gimbal.

Claims (54)

1. A pointing mechanism comprising:

a deployed boom having a rod shape;

a main body side gimbal to connect the deployed boom to a satellite main body and adjust a direction of the deployed boom; and

a thruster side gimbal to connect a thruster to the deployed boom and adjust a direction of the thruster, wherein

the pointing mechanism includes a first pointing mechanism and a second pointing mechanism each mounted on an artificial satellite,

each of the main body side gimbal and the thruster side gimbal is a two-axis gimbal,

the first pointing mechanism includes a first attachment portion located at one corner out of four corners on a first anti-earth-oriented surface side, and

the second pointing mechanism includes a second attachment portion located at a diagonal corner of the first attachment portion out of the four corners on a second anti-earth-oriented surface side, opposite the first anti-earth-oriented surface side.

2. The pointing mechanism according to claim 1 , wherein

the thruster side gimbal connects a first thruster group comprising a plurality of thrusters to the deployed boom, and

during orbit raising, when a first operation number which is the number of activated thrusters out of the first thruster group of the first pointing mechanism and a second operation number which is the number of activated thrusters out of a second thruster group connected to the deployed boom of the second pointing mechanism are different from each other, the direction of the deployed boom to which the first thruster group is connected and the direction of the deployed boom to which the second thruster group is connected are adjusted, a satellite center of gravity, the first thruster group and the second thruster group are projected on a plane having a traveling direction as a normal line during orbit raising, and

the satellite center of gravity, the first thruster group and the second thruster group are arranged on a same common straight line, so that a ratio of a first distance from the satellite center of gravity to the first thruster group and a second distance from the satellite center of gravity to the second thruster group in the plane is an inverse ratio of the first operation number and the second operation number.

3. The pointing mechanism according to claim 1 , wherein when the artificial satellite is accommodated in a rocket fairing, the direction of the deployed boom is configured to be adjusted to be parallel to a surface to which the main body side gimbal is attached.

4. The pointing mechanism according to claim 1 , wherein

the deployed boom has the longest length in a length tolerance range, and

the length tolerance range is a range satisfied by a length of the deployed boom to accommodate an entire pointing mechanism in a fairing envelope region in a state in which the direction of the deployed boom is configured to be adjusted to be parallel to the surface to which the main body side gimbal is attached.

5. The pointing mechanism according to claim 1 , wherein

when station keeping is performed, the direction of the deployed boom and the direction of the thruster are adjusted so that a firing direction angle formed by a firing direction of the thruster and a north-south direction of the artificial satellite is the minimum angle in an angle tolerance range, and

the angle tolerance range is a range satisfied by the firing direction angle so that a solar cell paddle does not enter a firing range of the thruster.

6. A pointing mechanism comprising:

a deployed boom having a rod shape;

a main body side gimbal to connect the deployed boom to a satellite main body and adjust a direction of the deployed boom; and

a thruster side gimbal to connect a thruster to the deployed boom and adjust a direction of the thruster, wherein

the pointing mechanism is mounted in a pair on an artificial satellite,

a first attachment portion to which the main body side gimbal is attached and a second attachment portion to which the main body side gimbal of another pointing mechanism of the pair of pointing mechanisms is attached are in rotationally symmetric positions about a satellite center of gravity as seen from an earth-oriented surface side,

the first attachment portion is located at one corner out of four corners on a first anti-earth-oriented surface side, and

the second attachment portion is located at a diagonal corner of the first attachment portion out of the four corners on a second anti-earth-oriented surface side, opposite the first anti-earth-oriented surface side,

the thruster includes a thruster base, and

for each of the pair of pointing mechanisms, a length from the main body side gimbal to the thruster base is substantially equal to a width of the respective anti-earth-oriented surface side.

7. A pointing mechanism comprising:

a deployed boom having a rod shape;

a main body side gimbal to connect the deployed boom to a satellite main body and adjust a direction of the deployed boom; and

a thruster side gimbal to connect a thruster to the deployed boom and adjust a direction of the thruster, wherein

the pointing mechanism is mounted in a pair on an artificial satellite,

a first attachment portion to which the main body side gimbal is attached and a second attachment portion to which the main body side gimbal of another pointing mechanism of the pair of pointing mechanisms is attached are in rotationally symmetric positions about a satellite center of gravity as seen from an earth-oriented surface side,

the first attachment portion is located at one corner out of corners on an anti-earth-oriented surface side, the first attachment portion is located on one of a south surface facing the south when the artificial satellite orbits the earth and a north surface facing the north when the artificial satellite orbits the earth, and

the second attachment portion is located at a diagonal corner of the first attachment portion out of the corners on the anti-earth-oriented surface side in the other surface out of the south surface and the north surface,

the thruster includes a thruster base, and

for each of the pair of pointing mechanisms, a length from the main body side gimbal to the thruster base is substantially equal to a width of the respective anti-earth-oriented surface side.

8. The pointing mechanism according to claim 6 , wherein

the thruster side gimbal connects a first thruster group comprising a plurality of thrusters to the deployed boom, and

during orbit raising, when a first operation number which is the number of activated thrusters out of the first thruster group and a second operation number which is the number of activated thrusters out of a second thruster group connected to the deployed boom of the other pointing mechanism are different from each other, the direction of the deployed boom to which the first thruster group is connected and the direction of the deployed boom to which the second thruster group is connected are adjusted, the satellite center of gravity, the first thruster group and the second thruster group are projected on a plane having the traveling direction as a normal line during orbit raising, and the satellite center of gravity, the first thruster group and the second thruster group are arranged on the same straight line, so that a ratio of a first distance from the satellite center of gravity to the first thruster group and a second distance from the satellite center of gravity to the second thruster group in the plane is an inverse ratio of the first operation number and the second operation number.

9. The pointing mechanism according to claim 6 , wherein when the artificial satellite is accommodated in a rocket fairing, the direction of the deployed boom is configured to be adjusted to be parallel to a surface to which the main body side gimbal is attached.

10. The pointing mechanism according to claim 6 , wherein

the deployed boom has the longest length in a length tolerance range, and

the length tolerance range is a range satisfied by a length of the deployed boom to accommodate an entire pointing mechanism in a fairing envelope region in a state in which the direction of the deployed boom is configured to be adjusted to be parallel to the surface to which the main body side gimbal is attached.

11. The pointing mechanism according to claim 6 , wherein

when station keeping is performed, the direction of the deployed boom and the direction of the thruster are adjusted so that a firing direction angle formed by a firing direction of the thruster and a north-south direction of the artificial satellite is the minimum angle in an angle tolerance range, and

the angle tolerance range is a range satisfied by the firing direction angle so that a solar cell paddle does not enter a firing range of the thruster.

12. The pointing mechanism according to claim 1 , wherein

the thruster of each of the first and second pointing mechanisms includes a thruster base, and

wherein for each pointing mechanism, a length from the main body side gimbal to the thruster base is substantially equal to a width of the respective anti-earth-oriented surface side.

13. The pointing mechanism according to claim 6 , wherein each of the main body side gimbal and the thruster side gimbal is a two-axis gimbal.

14. The pointing mechanism according to claim 7 , wherein each of the main body side gimbal and the thruster side gimbal is a two-axis gimbal.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 11, 2019
From: KAWAMURA, SHUNICHI
To: MITSUBISHI ELECTRIC CORPORATION
Reel/Frame 048567/0371 →
Priority Claims (1)
JP JP2016-190606 · Sep 29, 2016 · national
Continuity (1)
Related Publication 20190210744A1 · Jul 11, 2019