JPH05112299A - Thruster operating method in thrusting device of spacecraft - Google Patents

Abstract

PURPOSE: To minimize the influence of the thruster plume on experimental devices installed outside and to reduce propellant consumption, by firing thrusters separately and selectively when the thrust axes are almost parallel to a maneuver direction while a spacecraft is rotating about its spin axis. CONSTITUTION: First thrusters 301 , 302 and a pair of second thrusters 30 are installed at the periphery of a spacecraft, and each of thrust axes 401 , 402 is shifted relative to its radial direction by an offset angle α. The thrusters 301 , 302 are fired selectively and alternately when the thrust axes 401 , 402 are generally parallel to a vector D while a spacecraft is rotating to correct its orbital velocity. Therefore, the thruster 301 is fired when a transverse axis 60 is shifted by the angle α to a maneuver direction along the orbital velocity vector. and the thruster 302 is fired when a common support member of a pair of the thrusters 301 , 302 rotates around a spin axis 20 by the angle of 2α.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propulsion device for a spacecraft which is spin-stabilized by rotating a spacecraft such as a space satellite orbiting the earth around the spin axis of the spacecraft. The present invention relates to a method of operating a spacecraft propulsion thruster to increase the orbital spin rate of a spacecraft as the spacecraft rotates about a spacecraft spin axis.

[0002]

2. Description of the Related Art Propulsion devices include eight propulsion devices for operating a spacecraft by applying a reaction force to the spacecraft in order to adjust the orbital position of the spacecraft, the trajectory of the spacecraft or the attitude of the spacecraft. The control thrusters may be in one suitable plane. Thrusters, which are usually four to modify the spacecraft spin speed and spacecraft orbital speed, are individually placed around the spacecraft in a plane perpendicular to the spacecraft spin axis. ing. These four thrusters are arranged in a known "square" configuration, each thruster being arranged at each of the four corners of the rectangle, thus two pairs of thrusters being radially opposite one another.

As shown in FIG. 1, in a known propulsion system configuration, the thrusters of a pair of thrusters are radially offset with respect to multiple thrusters to increase orbit velocity of the spacecraft. Thrusters are simultaneously actuated over a portion of the spacecraft rotation cycle over rotation. The thruster axis 40 of the thruster 30 in the pair of thrusters is
Thruster axes of the thrusters in the pair of thrusters are parallel to each other and the thruster axes are parallel to the steering direction vector D along the orbit velocity vector over the partial period of the rotation cycle of the spacecraft 10. It is located in. To perform this maneuver, the thrusters in the pair of thrusters are actuated simultaneously to produce individual angular moments, which adjust the spin velocity of the spacecraft.

[0004]

This propulsion device configuration has a number of drawbacks, in particular the jet of propellant gas forming a plume or conical gas fumes at the thruster nozzle is used in experimental equipment, especially in space. It has been found that it tends to contaminate the optical surfaces of viewing devices located around the ship. Also, the high temperature of the gas jets significantly affects the performance of onboard instrumentation and the operation of the articulated booms that hold the instrumentation around the spacecraft. Lastly, the square configuration of the thrusters is costly and complicated, because in this configuration a separate propellant supply is required for each thruster. Therefore, in order to minimize the adverse effects of gas jets on board equipment without compromising the performance of the propulsion device in terms of propellant consumption and complexity of the propulsion device, the position of the thrusters and the order in which they are operated are Need to be optimized.

The object of the present invention is to remedy the above-mentioned drawbacks of prior art propulsion devices, in particular to minimize the effect of thruster plumes on experimental equipment mounted external to the spacecraft,
It is an object of the present invention to provide a method of operating a thruster in a spin-stabilized spacecraft propulsion device that ensures a reduction in propellant consumption while the spacecraft is maneuvering.

[0006]

SUMMARY OF THE INVENTION The invention comprises a thruster comprising a pair of thrusters juxtaposed on a common support member located at the periphery of a spacecraft, the thrusters being relative to a spin axis. Has a thruster axis that is perpendicular to the spacecraft's lateral axis by an offset angle of equal magnitude and opposite direction, with each thruster causing the spacecraft to rotate about the spacecraft spin axis. The spacecraft orbit velocity in the steering direction along the orbit velocity vector is characterized in that it is individually and selectively activated when the thruster axis of each thruster becomes substantially parallel to the steering direction. The method comprises actuating a thruster in a spacecraft propulsion system in which the spacecraft is spin-stabilized by rotating about the spacecraft spin axis to increase. In order to clarify other features and advantages of the present invention, the present invention will be described based on embodiments with reference to the accompanying drawings. However, this example does not limit the scope of the invention.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The same parts are designated by the same reference numerals in all figures. As shown in Figure 2,
Spacecraft 10 according to the present invention a pair of thrusters 30 _1, 30
₂ , the thrusters 30 ₁ and 30 ₂ are attached to the periphery of the spacecraft. The thrusters are located at radial positions that are symmetrical with respect to the spacecraft transverse axis 60 that intersects the spacecraft spin axis 20. As shown in this figure,
The two thrusters 30 ₁ and 30 ₂ are juxtaposed so that the radial position of the thrusters 30 ₁ and 30 ₂ substantially coincides with the lateral axis 60, and the thrusters 30 ₁ and 30 ₂ have a common support member 70 for spacecraft. Installed on. In this way, each thruster of the thruster pair is placed together at a common point on the periphery of the spacecraft. Therefore, the attachment point of the laboratory equipment can be located far away from the thruster to avoid the drawbacks of the prior art. The thruster propellant supply device and the power distribution device are also simplified. Similarly, the second pair of thrusters 30 is also provided on the periphery of the spacecraft and at a position opposite to the pair of thrusters 30 ₁ and 30 ₂ in the radial direction. As shown in this figure, the thruster axes 40 ₁ and 40 ₂ of the thrusters 30 ₁ and 30 ₂ are of the same size with respect to their respective radial positions, but are offset in direction by an offset angle α. ..

FIG. 3 shows a maneuver for modifying the angular velocity of a spacecraft,
For the maneuvers to modify the spacecraft's orbital velocity, and the combination of these two maneuvers, the basic "square" described above.
The propellant penalty (additional propellant requirement) in the propulsion device of the present invention is shown as a function of offset angle α, in contrast to the prior art configuration In this figure, α ₀ represents the offset angle of the above-mentioned basic configuration. The propellant penalty for angular velocity correction maneuvers depends only on the offset angle α. It is assumed that such a penalty does not exist for the offset angle α ₀ . In this figure, especially in the curve designated as the "spin control penalty", the propellant consumption for this type of maneuver decreases when the offset angle exceeds α ₀ and is minimal at an offset angle of 90 °. Note that The propellant penalty for maneuvering to modify the spacecraft's orbital velocity also depends on the offset angle α. There is no penalty for the α = 0 offset angle, as shown by the curve shown as "Orbital Speed Control Penalty".

In the first configuration, the maneuver that modifies the spacecraft's orbital velocity (the direction of this maneuver is indicated by the vector D in FIG. 2) causes two spacecraft spins while the spacecraft is spinning. The thrusters 30 ₁ and 30 ₂ are actuated at the same time, so that the parallel reaction force in the same direction as the vector D is transmitted to the spacecraft. As shown in FIG. 3, in particular in the curve designated as "total penalty", the total propellant penalty in a propulsion device according to this configuration is at a 25 ° offset angle compared to the basic configuration described above. On the contrary, it is the smallest. The minimum penalty is about 6.259 kg of propellant per thruster.

[0010] In the configuration according to the present invention, since the steering to correct the orbital velocity of the spacecraft, when the spacecraft 10 is rotating about the spacecraft spin axis, the thruster 30 _1, 30
When substantially parallel to the direction of the vector D of steering the respective thruster shaft 40 ₁ of _2, 40 ₂ along the orbital velocity vector, selectively and operated alternatively thrusters 30 _1, 30 ₂ .. The thruster 30 ₁ is therefore such that when the common support member of the thruster pair 30 ₁ , 30 ₂ is in position A, in other words the axis of symmetry or transverse axis 60 is angled with respect to the direction of maneuver along the orbit velocity vector. It is operated almost at the time of being located at α. Thruster 30 ₂
Is actuated when the common supporting member of the thruster pair 30 ₁ and 30 ₂ reaches the position B by rotating up to an angle of 2α with respect to the spin axis 20. Each thruster 30 ₁ and 30 ₂
Thruster 30 _1, 30 ₂ of the thruster axes 40 _1, 40 ₂
Is operated for part of the spacecraft rotation period, where is parallel to the direction of the orbital velocity vector. This method avoids propellant penalties to the basic configuration for maneuvering to modify spacecraft orbital velocity. In this second configuration, the offset angle can also be selected to reduce the effect of the thruster plume on the measuring instrument. At offset angle α, the propellant configuration used in the present invention does not create a propellant penalty relative to the basic "square" configuration of the prior art. It is self-evident that the invention is not limited to the embodiments described above, and that various modifications can be realized without departing from the scope of the invention.

[Brief description of drawings]

FIG. 1 is a layout of a spacecraft equipped with a prior art propulsion device.

FIG. 2 is a layout of a spacecraft equipped with the propulsion device of the present invention.

FIG. 3 illustrates the fuel (propellant) penalty of the propulsion device of FIG. 2 for the basic configuration described above as a function of thruster offset angle for various maneuvers of the spacecraft.

[Explanation of symbols]

10 Spacecraft 20 Spin Axis 30 ₁ , 30 ₂ First Thruster Pair 30 Second Thruster Pair 40 ₁ , 40 ₂ Thruster Axis 50 Peripheral 60 Transverse Axis 70 Support Member D Steering Direction

Claims (1)

[Claims] 1. A propulsion device comprises a pair of thrusters juxtaposed on a common support member located at the periphery of a spacecraft, the thrusters being perpendicular to the spin axis and of equal absolute value. Having thruster axes whose directions are offset with respect to the transverse axis of the spacecraft by opposite offset angles,
Each thruster is individually and selectively actuated when the thruster axis of each thruster is approximately parallel to the steering direction as the spacecraft rotates about the spacecraft spin axis. A thruster actuation method in a spacecraft propulsion device that is spin-stabilized by rotation about a spin axis to increase the spacecraft's orbital velocity in the steering direction along the orbital velocity vector.