JPH08130097A - Discharge preventive apparatus for aerospace vehicle - Google Patents

Abstract

PURPOSE: To surely prevent a discharge phenomenon between mutually approaching aerospace vehicles. CONSTITUTION: An ion engine 11 for plasma generation is installed in a first aerospace vehicle 10, the ion engine 11 is driven and controlled based on the potential difference in the space between the vehicle 10 and a second aerospace vehicle 15, and plasma is discharged toward the second aerospace vehicle 15. Consequently, the charge of the surface of the second aerospace vehicle 15 is neutralized and the potential of the surface is made almost the same as that of the surface of the first aerospace vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge prevention device used for suppressing discharge of spacecraft such as artificial satellites and orbital working machines.

[0002]

2. Description of the Related Art In general, a spacecraft has an extremely low plasma density in outer space, and its surface is negative by several kilovolts or more against the surrounding plasma potential due to collision of electrons and protons having high energy. It is known to be charged. This charging phenomenon is greatly changed depending on the substance on the surface of the spacecraft and the presence / absence of sunlight irradiation, and the potential distribution on the surface of the spacecraft becomes extremely complicated.

In particular, the electrification phenomenon of a spacecraft is often observed in the shadow of the earth in high altitude orbit, that is, in the shade, and during the sunshine period when sunlight is directly irradiated on the spacecraft. In this case, the current from the surrounding plasma and the photoelectron current generated by sunlight cancel each other out, so that they do not occur so much.

As described above, the charging phenomenon is charged to a very large negative potential as compared with the plasma potential around the spacecraft due to the absence of inflow of photoelectron current due to sunlight in the shade period. This is because during the daylight, the negative potential is also charged in the shadow of the spacecraft.

By the way, in the field of recent space development, spacecrafts are rendezvous and docked with each other, or a spacecraft called an in-orbit working machine is used to perform various maintenance services for other spacecrafts. A plan to implement is underway.

However, in the above spacecraft, when the other spacecraft approaches the other spacecraft, if the other spacecraft is negatively charged, the potential difference becomes "0". However, there is a problem in that a sudden movement of electric charge, that is, a discharge phenomenon occurs, which causes damage to the spacecraft itself or causes malfunction of electronic equipment due to electromagnetic noise even if it is not destroyed.

The problem of such a discharge phenomenon is that in space stations, stationary platforms, etc. planned in the field of future space development, so-called docking operation such as mooring a spacecraft such as a working machine to the space station or platform. It is important to be repeated many times

[0008]

As described above, in the conventional spacecraft, when it approaches another spacecraft, there is a risk that a discharge phenomenon may occur and damage or the like may occur.
The present invention has been made in view of the above circumstances, and a discharge preventive device for a spacecraft that realizes reliable suppression of a discharge phenomenon so as to contribute to the realization of highly safe approaching operations of spacecraft. The purpose is to provide.

[0009]

The present invention, which is provided in a first spacecraft, discharges plasma toward an approaching second spacecraft, and the second spacecraft is discharged. Plasma generating means for neutralizing the electric charge charged on the surface of the, a potential detection sensor for measuring the space potential facing the first and second spacecraft, based on the detection of the potential detection sensor, The potential difference between the surfaces of the first and the second spacecraft is obtained, and the plasma generation means is driven and controlled based on the potential difference to emit plasma, and the potential of the surface of the second spacecraft is changed. A discharge preventing device for a spacecraft is provided with a control means for setting the potential of the surface of the first spacecraft to be substantially the same as the potential of the surface.

[0010]

According to the above construction, the plasma generating means emits plasma toward the second spacecraft,
The electric charge on the surface of the second spacecraft is neutralized and set to approximately the same potential as the potential of the surface of the first spacecraft. As a result, the first and second spacecraft do not generate a discharge phenomenon even if they approach each other.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a discharge preventive apparatus for a spacecraft according to an embodiment of the present invention, in which a first spacecraft 10, such as an on-orbit working vehicle, is equipped with an ion engine 11 as a plasma generating means. It The ion engine 11 has an accelerating voltage of about several tens of volts, and its signal input terminal is connected to the power supply circuit 12. Power supply circuit 1
2, the control electronics section 13 is connected to the signal input terminal thereof, and the control electronics section 13 is connected to the output terminal of a potential detection sensor 14 represented by, for example, a Langmuir probe.

The potential detection sensor 14 has one detection end provided on the approach side surface of the first spacecraft 10, and the other detection end provided on the approach side surface so as to project into the outer space. The detection signal from the detection end is output to the control electronics section 13. The control electronics section 13 obtains a potential difference between the outer space and the surface of the first spacecraft 10 based on the input detection signal, generates an engine drive signal based on this potential difference, and outputs it to the power supply circuit 12. .
The power supply circuit 12 drives and controls the ion engine 11 based on the input engine drive signal. Here, in the ion engine 11, a high voltage is applied to the anode and the cathode based on the engine drive signal to ionize an inert gas such as helium to generate plasma, which is emitted toward outer space. It gives almost no thrust to the spacecraft 1 and does not cause any disturbance to the attitude.

The power supply circuit 12 and the control electronics section 13 are each connected to a bus power supply, and their operations are controlled by a command signal from a central processing unit (not shown) via the bus power supply.

In the above structure, the first spacecraft 10
Approaches the second spacecraft 15, for example to service the second spacecraft 15 or to perform rendezvous docking, the potential sensing sensor 14
The electric potential of outer space and the electric potential of the surface of the first spacecraft 10 and its vicinity are detected, and the detection signal is output to the control electronics unit 13. Control electronics section 13
Is a potential difference between the surface potential of the second spacecraft 15 and the surface potential of the first spacecraft 10 from the input detection signal, and this potential difference is a preset constant value (for example, 5
00 V) or more, an engine drive signal corresponding to this potential difference is generated and output to the power supply circuit 12. The power supply circuit 12 drives and controls the ion engine 11 in response to the engine drive signal, and discharges plasma toward the second spacecraft 15. As a result, the electric charges on the surface of the second spacecraft 15 are neutralized by the plasma,
The potential is varied to be substantially the same as the surface of the first spacecraft 10.
In this state, the first spacecraft 10 further approaches the second spacecraft 15 to a position where desired service or rendezvous docking can be performed.

The control electronics section 13 appropriately drives and controls the ion engine 11 depending on which of the first and second spacecraft 10, 15 is charged to a negative potential, And the electric potentials of the surfaces of the second spacecraft 10, 15 are set to substantially the same electric potential.

As described above, in the discharge preventive device for the spacecraft, the first spacecraft 10 is provided with the ion engine 11 for plasma generation, and the ion engine 11 is approached to the second spacecraft 15 approaching. Driving control is performed according to the potential difference in the space, and plasma is emitted toward the second spacecraft 15, thereby neutralizing the charge on the surface of the second spacecraft 15 and It is configured so as to be set to substantially the same potential as the surface potential of the navigation body 10.

According to this, the first and second spacecraft 10, 15 are in service or rendezvous.
When approaching for docking, the mutual surfaces are automatically set to substantially the same potential, so that the discharge phenomenon due to charging is reliably prevented. As a result, damage due to the discharge phenomenon and generation of electromagnetic noise can be prevented, and a highly safe approaching operation is realized.

In the above embodiment, the case where the plasma generating means is configured by using the ion engine 11 has been described, but the plasma generating means is not limited to this and various configurations are possible. In this case, the working fluid is preferably a gas having a light mass so that the surface of the spacecraft is not contaminated and the disturbance to the attitude of the spacecraft can be suppressed as much as possible. Therefore, it is needless to say that the present invention is not limited to the above-described embodiment, and that various modifications can be made without departing from the scope of the present invention.

[0019]

As described in detail above, according to the present invention, a spacecraft that reliably prevents the discharge phenomenon so as to contribute to the realization of highly safe approaching operations of the spacecraft. It is possible to provide the discharge prevention device.

[Brief description of drawings]

FIG. 1 is a diagram showing a discharge preventive device for a spacecraft according to an embodiment of the present invention.

[Explanation of symbols]

 10 ... The first spacecraft. 11 ... Ion engine. 12 ... Power supply circuit. 13 ... Control electronics department. 14 ... Potential detection sensor. 15 ... The second spacecraft.

Claims (2)

[Claims] 1. A charge provided on a first spacecraft, which discharges plasma toward an approaching second spacecraft and charges the surface of the second spacecraft. Plasma generating means for neutralizing the space, a potential detecting sensor for measuring a space potential facing the first and second spacecraft, and the first and second space based on the detection by the potential detecting sensor. The potential difference between the surfaces of the navigation body is obtained, and the plasma generation means is driven and controlled based on the potential difference to emit plasma, and the potential of the surface of the second spacecraft is adjusted to that of the first spacecraft. A discharge preventive device for a spacecraft, comprising: a control means for setting the surface potential to be substantially the same as the potential. 2. The discharge preventive apparatus for a spacecraft according to claim 1, wherein the plasma generating means is composed of an ion engine.