JPH0524596A - Active control type aerobrake system - Google Patents

Abstract

PURPOSE:To provide a fixed braking force even when atmospheric density and aerodynamic coefficient fluctuate by, in an active control type aerobrake system used in the case where a spacecraft returns onto a low altitude orbit for going round the earth, changing the angle of an air resistance plate for controlling aerodynamic control acceleration. CONSTITUTION:A spacecraft 1 such as an transport airplane between the orbits (OTV) is provided with an accelerometer 3 to detect braking acceleration caused by an aerobrake and an air resistance plate 2 being variable in an aera where the aerobrake acts, and moreover with an actuator 5 to drive and to control the opening angle of the air resistance plate 2 and a control electronics 4, and the brake acceleration acting on the spacecraft 1 is measured by the accelerometer 3, and sent to the control electronics 4. An acceleration signal inputted into the control electronics 4 is compared with a preset acceleration profile for the detection of an error, and the opening angle control signal of the air resistance plate 2 is then sent to the actuator 5 basing on the square root of the error for developing the air resistance plate 2 to a fixed angle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an inter-orbit transport aircraft (OTV).
When an orbital spacecraft such as a spacecraft transits from a high altitude orbit to a low altitude orbit around the earth, an active control type that decelerates the spacecraft by generating air resistance for the purpose of greatly saving the fuel for orbital transition Aero brake system.

[0002]

2. Description of the Related Art Conventionally, as an aero brake of this type, one using a fixed air resistance plate or a balloon type value has been considered.

[0003]

Since the conventional aero brake described above uses the fixed air resistance plate or the balloon type float, the area receiving the air resistance becomes constant. On the other hand, the density of the Earth's upper atmosphere fluctuates greatly due to the influence of solar activity. As a result,
In a conventional aero brake which receives air resistance in a certain area, it is difficult to obtain a desired braking force accurately, and there is a drawback that a large restriction is imposed on its use.

[0004]

The active control type aerobrake system of the present invention greatly saves fuel consumption for orbit transition when an inter-orbit transport aircraft (OTV) returns to a low altitude orbit. In an aero brake used for the purpose of, an accelerometer for detecting a braking acceleration applied to the OTV by air resistance, an air resistance plate whose area for receiving the air resistance is variable, and a detection result of the accelerometer are used. An actuator for driving and controlling the air resistance plate and control electronics are provided.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIGS. 1A and 1B are a front view and a side view of an embodiment of the present invention.

In this embodiment, an accelerometer 3 for detecting a braking acceleration applied to the spacecraft 1 by an aero brake, an air resistance plate 2 having a variable area for receiving the aero brake, and an opening angle of the air resistance plate 2 are driven. Actuator 5 to control
And control electronics 4.

In this embodiment, the accelerometer 3 is used.
Measures the braking acceleration applied to the spacecraft 1 by the aero brake and outputs it to the control electronics 4. The control electronics 4 compares the input acceleration signal with a preset acceleration profile and detects the error. The square root of this error is calculated and used as the opening angle control signal for the air resistance plate 2. This control signal is output to the actuator 5. Actuator 5
Then, the opening angle of the air resistance plate 2 is drive-controlled according to the control signal. As a result, the opening angle of the air resistance plate 2 can be freely changed from the fully deployed state to the partially deployed state indicated by reference numerals 6 and 7, and the area receiving the aero brake is variable, so that a predetermined braking force can be obtained with high accuracy. .

[0009]

As described above, according to the present invention, the aerodynamic braking acceleration received by the spacecraft through the air resistance plate is measured, and the area of the air resistance plate is controlled according to the difference from the preset aerodynamic braking acceleration profile. By doing so, there is an effect that a predetermined braking force can be obtained even if the atmospheric density and aerodynamic coefficient of the upper atmosphere of the earth fluctuate, and the spacecraft can be braked with high accuracy.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, in which FIG. 1 (a) is a front view and FIG. 1 (b) is a side view.

[Explanation of symbols]

1 Spacecraft 2 Air resistance plate (fully deployed) 3 accelerometer 4 Control Eletronics 5 actuators 6,7 Air resistance plate (partially expanded state)

Claims (2)

[Claims] 1. An aerobrake used for the purpose of greatly saving the consumption of fuel for orbit transition when an inter-orbit transport aircraft (OTV) or the like returns to a low earth orbit. An accelerometer for detecting a braking acceleration received by air resistance, an air resistance plate whose area for receiving the air resistance is variable, and an actuator and control electronics for driving and controlling the air resistance plate based on the detection result of the accelerometer. An active control type aerobrake system characterized by the following. 2. The opening angle of the air resistance plate is drive-controlled by the actuator.
The active control type aero brake system described.