JP2021017086A - Probe, overturn prevention method, and overturn prevention control device - Google Patents

Abstract

To provide a system for preventing a probe from overturning at the time of landing when the probe shall land on an astronomical body with weak gravitational force.SOLUTION: A probe 100 includes: a plurality of thrusters 102; a sensor group 110; and an overturn prevention control device 200. The plurality of thrusters 102 are mounted to the probe 100 such that a direction opposite to a ground direction at the time of landing onto an astronomical body is a jetting direction, and they generate propulsive power in the ground direction according to jetting at the time of landing onto the astronomical body. At the time of landing onto the astronomical body, the overturn prevention control device 200 selects a part of thrusters 102 among the plurality of thrusters 102 on the basis of attitude angle information obtained by the sensor group 110, and only the selected part of thrusters 102 are caused to jet.SELECTED DRAWING: Figure 3

Description

The present invention relates to a technique for preventing a spacecraft landing on a celestial body from tipping over.

Conventionally, when a spacecraft lands on a celestial body, the frictional force generated between the ground plane of the landing gear and the ground of the celestial body and the damping force generated by the spring or damper of the landing gear have been used to prevent the spacecraft from tipping over. ..

Patent Document 1 discloses an astronomical spacecraft including a landing gear that absorbs an impact at the time of landing and an airbag that absorbs an impact at the time of a fall.

Japanese Unexamined Patent Publication No. 2002-205689

In the following cases, it is difficult to prevent the spacecraft from tipping over by the conventional method that relies only on the landing gear.
・ The gravity of the celestial body on which the spacecraft lands is small.
・ Land with the spacecraft tilted significantly.
・ The inclination of the spacecraft at the time of landing is small, but the descent speed of the spacecraft is fast.
In addition, depending on conditions such as the inclination of the ground or the coefficient of friction of the ground, it is difficult to prevent the spacecraft from tipping over by the conventional method.

An object of the present invention is to make it possible to prevent the spacecraft from tipping over during landing even in a situation where the spacecraft is likely to tip over during landing, such as when the spacecraft lands on a celestial body with low gravity. ..

The spacecraft of the present invention is a spacecraft that lands on a celestial body and conducts exploration.
With a plurality of thrusters attached to the spacecraft so that the direction opposite to the ground direction at the time of landing on the celestial body is the injection direction, and generating propulsive force toward the ground by injection at the time of landing on the celestial body. ,
A group of sensors that obtain attitude angle information of the spacecraft, and
A fall prevention control device that selects a part of the thrusters from the plurality of thrusters based on the attitude angle information obtained by the sensor group at the time of landing on the celestial body and causes only the selected thrusters to inject. To be equipped.

According to the present invention, it is possible to prevent the spacecraft from overturning at the time of landing even in a situation where the spacecraft is likely to overturn at the time of landing, such as when the spacecraft lands on a celestial body with low gravity.

The perspective view which shows the outline of the appearance of the spacecraft 100 in Embodiment 1. FIG. The perspective view which shows the outline of the appearance of the spacecraft 100 in Embodiment 1. FIG. The block diagram of the spacecraft 100 in Embodiment 1. FIG. The flowchart of the fall prevention control method in Embodiment 1. The schematic diagram of the attitude control (S140) in Embodiment 1. The flowchart of attitude control (S140) in Embodiment 1. The schematic diagram of the grounding boost control (S150) in Embodiment 1.

In embodiments and drawings, the same or corresponding elements are designated by the same reference numerals. Descriptions of elements with the same reference numerals as the described elements will be omitted or simplified as appropriate. The arrows in the figure mainly indicate the flow of data or the flow of processing.

Embodiment 1.
The spacecraft 100 will be described with reference to FIGS. 1 to 7.

The spacecraft 100 is a spacecraft that lands on a celestial body and conducts exploration, and has a fall prevention function. The fall prevention function is a function of preventing the spacecraft 100 from falling when landing on a celestial body.

The direction in which the ground of the celestial body is located at the time of landing on the celestial body is called the "ground direction". Further, the direction opposite to the ground direction, that is, above the ground of the celestial body is referred to as "sky direction".

*** Explanation of configuration ***
The configuration of the spacecraft 100 will be described with reference to FIGS. 1, 2 and 3.
1 and 2 are perspective views showing an outline of the appearance of the spacecraft 100.
FIG. 3 is a block diagram showing a main configuration of the spacecraft 100.

As shown in FIG. 1, the spacecraft 100 includes a plurality of landing gears (101A to 101D). Specifically, the spacecraft 100 includes four landing gears. However, the spacecraft 100 may be provided with three landing gears or may be provided with five or more landing gears.
When any one of the plurality of landing gears (101A to 101D) is not specified, each is referred to as a landing gear 101.
The plurality of landing gears 101 are attached to the spacecraft 100 so that the spacecraft 100 can be supported when the spacecraft 100 lands on a celestial body without tipping over. Specifically, the plurality of landing gears 101 are attached to the lower part of the spacecraft 100. Further, the plurality of spacecraft 100 are arranged at positions separated from each other. However, the plurality of landing gears 101 do not necessarily have to be attached to the lower part of the spacecraft 100. For example, each landing gear 101 may be fixed to the side of the spacecraft 100 at one end, bent toward the ground at the intermediate portion, and in contact with the ground of the celestial body at the other end.
It is preferred that each landing gear 101 has a spring or damper. The spring or damper assists the fall prevention function.

As shown in FIG. 2, the spacecraft 100 includes a plurality of thrusters (102A to 102D). Specifically, the spacecraft 100 includes four thrusters. However, the spacecraft 100 may include two or three thrusters, or may include five or more thrusters.
When any one of the plurality of thrusters (102A to 102D) is not specified, each is referred to as a thruster 102. The thruster 102 is also called an actuator.
The plurality of thrusters 102 are attached to the spacecraft 100 so that the direction opposite to the ground direction at the time of landing on the celestial body is the injection direction. Further, the plurality of thrusters 102 are arranged at positions separated from each other. Specifically, the plurality of thrusters 102 are attached to the upper part of the spacecraft 100. However, the plurality of thrusters 102 do not necessarily have to be attached to the upper part of the spacecraft 100. For example, each thruster 102 may be attached to the spacecraft 100 using an arm. In this case, the arm is fixed to the side portion of the spacecraft 100 at one end and bent toward the sky at the intermediate portion. Then, the thruster 102 is arranged at the other end of the arm.
The plurality of thrusters 102 generate propulsive force toward the ground by injection when landing on a celestial body.

As shown in FIGS. 1 and 2, the spacecraft 100 includes solar cell paddles 109 on the front, rear, left and right sides.

As shown in FIG. 3, the spacecraft 100 includes a plurality of landing gears 101, a plurality of thrusters 102, a solar cell paddle 109, a sensor group 110, an exploration device 190, and a fall prevention control device 200.

The sensor group 110 is one or more sensors that obtain the attitude angle information of the spacecraft 100 and the velocity amount information of the spacecraft 100.
Specific examples of the sensor group 110 are IMU111 and STT112.

The attitude angle information of the spacecraft 100 is information for specifying the attitude angle of the spacecraft 100. The fluctuation of the attitude angle of the spacecraft 100 is called dynamics.
Specifically, the attitude angle information is at least one of the attitude angle of the probe 100 in the inertial system, the angular velocity of the probe 100 in the inertial system, and the stellar information. The stellar information indicates the direction in which each of the plurality of stars is located. Further, the attitude angle information includes the angular velocity of the spacecraft 100 in the inertial system.

The speed amount information of the spacecraft 100 is information for specifying the speed amount of the spacecraft 100.
Specifically, the velocity amount information is at least one of velocity, acceleration, and angular velocity.

The IMU 111 is an inertial measurement unit (Inertial Measurement Unit).
At each time, the IMU 111 measures the acceleration of the spacecraft 100 and calculates the speed of the spacecraft 100 based on the measured acceleration. Further, the IMU 111 measures the angular velocity of the spacecraft 100 and calculates the attitude angle of the spacecraft 100 based on the measured angular velocity.

The STT112 is a Star Tracker.
At each time, the STT 112 measures the direction in which each of the plurality of stars is located, and outputs star information indicating the measurement result.

The exploration device 190 is a device for exploring celestial bodies. For example, the exploration device 190 is a device that collects stone and sand samples from the ground of a celestial body.

The fall prevention control device 200 is a computer that controls to realize the fall prevention function.
At the time of landing on a celestial body, the fall prevention control device 200 selects a part of the thrusters 102 from a plurality of thrusters 102 based on the attitude angle information obtained by the sensor group 110, and causes some of the selected thrusters to inject. .. Alternatively, the fall prevention control device 200 causes all of the plurality of thrusters 102 to inject at the time of landing on the celestial body.

The fall prevention control device 200 includes hardware such as a processing circuit 210 and an input / output interface 220.

The processing circuit 210 is hardware that realizes the landing detection unit 211 and the fall prevention control unit 212. Each of the landing detection unit 211 and the fall prevention control unit 212 will be described later.
The processing circuit 210 may be dedicated hardware, a processor that executes a program stored in a memory, or a combination thereof.
Dedicated hardware is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.
ASIC is an abbreviation for Application Specific Integrated Circuit.
FPGA is an abbreviation for Field Programmable Gate Array.

The input / output interface 220 is a port for connecting another device to the fall prevention control device 200. Specifically, the sensor group 110 and the plurality of thrusters 102 are connected to the input / output interface 220, respectively.

*** Explanation of operation ***
The procedure for operating the spacecraft 100 by the fall prevention function corresponds to the fall prevention method. The operation procedure of the fall prevention control device 200 corresponds to the fall prevention control method. Further, the operation procedure of the fall prevention control device 200 corresponds to the processing procedure by the fall prevention control program.

A fall prevention control method will be described with reference to FIG.
The fall prevention control method is started at a specific timing after the landing sequence is started. The landing sequence is a specific procedure for landing the spacecraft 100 on a celestial body.

In step S110, the landing detection unit 211 detects the start of landing based on the velocity amount information obtained by the sensor group 110.
The start of landing means the start of landing on a celestial body. For example, the time when at least one of the plurality of landing gears 101 first touches the ground of the celestial body is the start of landing on the celestial body.

At the start of landing on a celestial body, the speed of the spacecraft 100 changes rapidly. Therefore, the landing detection unit 211 detects the start of landing on the celestial body as follows. However, the procedure shown below is an example of the procedure for detecting the start of landing on a celestial body.
First, the landing detection unit 211 acquires the current speed amount information from the IMU 111.
Next, the landing detection unit 211 calculates the difference between the speed amount indicated by the previously acquired speed amount information and the speed amount indicated by the speed amount information acquired this time. For example, the difference in acceleration toward the ground is calculated.
Then, the landing detection unit 211 compares the calculated difference with the threshold value. When the calculated difference is larger than the threshold value, the landing detection unit 211 detects the start of landing on the celestial body.

Step S110 is repeated until the start of landing on the celestial body is detected.
If the start of landing on the celestial body is detected, the process proceeds to step S120.

In step S120, the fall prevention control unit 212 acquires the current attitude angle information from the sensor group 110.

In step S130, the fall prevention control unit 212 determines whether the correct attitude angle information can be obtained by the sensor group 110.

If the sensor group 110 cannot obtain the attitude angle information for some reason, in step S120, the fall prevention control unit 212 cannot acquire the attitude angle information from the sensor group 110. In this case, the fall prevention control unit 212 determines that the correct attitude angle information could not be obtained by the sensor group 110.
For example, when the attitude angle information cannot be acquired from either the IMU 111 or the STT 112, the fall prevention control unit 212 determines that the correct attitude angle information could not be obtained by the sensor group 110.

Although the attitude angle information could be acquired from the sensor group 110, when the acquired attitude angle information was abnormal information, the fall prevention control unit 212 could not obtain the correct attitude angle information by the sensor group 110. judge.
For example, when both the attitude angle information acquired from the IMU 111 and the attitude angle information acquired from the STT 112 are abnormal information, the fall prevention control unit 212 may obtain the correct attitude angle information by the sensor group 110. Judge that it could not be done.

The fall prevention control unit 212 may determine whether or not the posture angle information acquired from the sensor group 110 is abnormal information as follows.
When the difference between the attitude angle previously acquired from the IMU 111 as the attitude angle information and the attitude angle acquired this time from the IMU 111 as the attitude angle information is larger than the threshold value, the fall prevention control unit 212 uses the attitude angle information acquired from the IMU 111. It may be determined that the information is abnormal.

When the number of stars in the star information acquired from the STT 112 as the attitude angle information is less than the threshold value, the fall prevention control unit 212 may determine that the attitude angle information acquired from the STT 112 is abnormal information.

When the difference between the attitude angle acquired from the IMU 111 as the attitude angle information and the attitude angle calculated based on the stellar information acquired from the STT 112 as the attitude angle information is larger than the threshold value, the fall prevention control unit 212 starts from the sensor group 110. It may be determined that the acquired posture angle information is abnormal information.

If the correct attitude angle information can be obtained by the sensor group 110, the process proceeds to step S140.
If the correct attitude angle information cannot be obtained by the sensor group 110, the process proceeds to step S150.

In step S140, the fall prevention control unit 212 executes attitude control.
Attitude control is a control that prevents the spacecraft 100 from tipping over by selecting a part of the thrusters 102 based on the attitude angle of the spacecraft 100 and causing some of the thrusters 102 to inject.

The outline of the attitude control (S140) will be described with reference to FIG.
The spacecraft 100 is tilted to the right with respect to the ground of the celestial body. Then, if the spacecraft 100 continues to tilt to the right, the solar cell paddle 109 on the right side comes into contact with the ground of the celestial body. That is, the spacecraft 100 falls to the right.
Therefore, the fall prevention control unit 212 does not inject the thruster 102B on the right side, but causes the thruster 102A on the left side to inject.
As a result, a propulsive force toward the ground is generated on the left side of the spacecraft 100, and the inclination of the spacecraft 100 is improved. Therefore, the spacecraft 100 does not tip over to the right.

The procedure of attitude control (S140) will be described with reference to FIG.
In step S141, the fall prevention control unit 212 identifies the attitude angle of the spacecraft 100 in the inertial system by using the correct attitude angle information acquired from the sensor group 110.
For example, the fall prevention control unit 212 uses the attitude angle acquired from the IMU 111 as the attitude angle information as the attitude angle of the spacecraft 100 in the inertial system.
For example, the fall prevention control unit 212 calculates the attitude angle of the spacecraft 100 in the inertial system by using the stellar information acquired from the STT 112 as the attitude angle information. This calculation method is a conventional technique. That is, the method of calculating the attitude angle using the start racker is a conventional technique.

Further, the fall prevention control unit 212 identifies the angular velocity of the probe 100 in the inertial system by using the correct attitude angle information acquired from the sensor group 110.
For example, the fall prevention control unit 212 uses the angular velocity acquired from the IMU 111 as the attitude angle information as the angular velocity of the spacecraft 100 in the inertial system.

In step S142, the fall prevention control unit 212 converts the attitude angle of the spacecraft 100 in the inertial system into the attitude angle of the spacecraft 100 in the ground fixed coordinate system.
The ground fixed coordinate system is a coordinate system defined with reference to the ground of a celestial body. The method of determining the ground fixed coordinate system is a prior art. For example, the spacecraft 100 includes a camera for photographing the ground of a celestial body. This camera provides an image of the ground of a celestial body. The fall prevention control unit 212 generates a topographic map based on the obtained image, and determines the ground fixed coordinate system based on the generated topographic map.
The attitude angle of the spacecraft 100 in the ground fixed coordinate system represents the inclination of the spacecraft 100 with respect to the ground of the celestial body.

Further, the fall prevention control unit 212 converts the angular velocity of the spacecraft 100 in the inertial system into the angular velocity of the spacecraft 100 in the ground fixed coordinate system.

In step S143, the fall prevention control unit 212 determines whether or not there is a fall risk based on the attitude angle of the spacecraft 100 in the ground fixed coordinate system.

The fall prevention control unit 212 determines whether or not there is a fall risk as follows.
The fall prevention control unit 212 determines whether the attitude angle of the spacecraft 100 in the ground fixed coordinate system is included in the allowable range. This permissible range is a range determined as a range of attitude angles for preventing the spacecraft 100 from tipping over. If the attitude angle of the spacecraft 100 in the ground fixed coordinate system is not included in the allowable range, the fall prevention control unit 212 determines that there is a fall risk.
The fall prevention control unit 212 may determine the presence or absence of a fall risk in consideration of the angular velocity of the spacecraft 100 in the ground fixed coordinate system. For example, the fall prevention control unit 212 adjusts the above allowable range based on the angular velocity of the spacecraft 100 in the ground fixed coordinate system. Specifically, the fall prevention control unit 212 specifies the direction in which the spacecraft 100 is rotating in the roll direction or the pitch direction based on the angular velocity of the spacecraft 100. Then, the fall prevention control unit 212 narrows the allowable range in the specified direction.

If it is determined that there is a fall risk, the process proceeds to step S144.
If it is determined that there is no risk of falling, the process ends.

In step S144, the fall prevention control unit 212 selects a part of the thrusters 102 from the plurality of thrusters 102 based on the attitude angle of the spacecraft 100 in the ground fixed coordinate system.
Specifically, the fall prevention control unit 212 selects one or a plurality of thrusters 102 arranged in a direction opposite to the direction in which the spacecraft 100 is tilted.

In step S145, the fall prevention control unit 212 controls a plurality of thrusters 102 so that only a part of the selected thrusters 102 are injected.

Returning to FIG. 4, the description continues from step S150.
In step S150, the fall prevention control unit 212 executes grounding boost control.
The grounding boost control is a control for preventing the spacecraft 100 from tipping over by causing all of the plurality of thrusters 102 to inject.

That is, the fall prevention control unit 212 controls the plurality of thrusters 102 to cause all of the plurality of thrusters 102 to perform injection.

The outline of the grounding boost control (S150) will be described with reference to FIG. 7.
The spacecraft 100 is tilted to the right with respect to the ground of the celestial body. Then, if the spacecraft 100 continues to tilt to the right, the solar cell paddle 109 on the right side comes into contact with the ground of the celestial body. That is, the spacecraft 100 falls to the right.
However, since the correct attitude angle information could not be obtained by the sensor group 110, the state of inclination of the spacecraft 100 is unknown.
Therefore, the fall prevention control unit 212 causes both the left and right thrusters (102A, 102B) to inject.
As a result, a propulsive force is generated in the spacecraft 100 toward the ground, and the inclination of the spacecraft 100 is improved. Therefore, the spacecraft 100 does not tip over to the right.

In step S160, the landing detection unit 211 detects the completion of landing based on the velocity amount information obtained by the sensor group 110.
Completion of landing means completion of landing on the celestial body. For example, the time when all of the plurality of landing gears 101 are in contact with the ground of the celestial body and the spacecraft 100 is stopped is the time when the landing on the celestial body is completed.

When the landing on the celestial body is completed, the spacecraft 100 comes to rest. Therefore, the landing detection unit 211 detects the completion of landing on the celestial body as follows.
First, the landing detection unit 211 acquires the current speed amount information from the IMU 111.
Then, the landing detection unit 211 determines whether the speed amount (for example, angular velocity) indicated by the acquired speed amount information is zero. When the speed amount indicated by the acquired speed amount information is zero, the landing detection unit 211 detects the completion of landing on the celestial body.

If the completion of landing on the celestial body is not detected, the process proceeds to step S120.
When the completion of landing on the celestial body is detected, the process ends.

*** Explanation of Examples ***
The fall prevention control device 200 does not have to execute the grounding boost control (S150). For example, the fall prevention control device 200 stops the attitude control (S140) while the correct attitude angle information cannot be obtained.
The fall prevention control device 200 does not have to execute the attitude control (S140). For example, the fall prevention control device 200 always executes grounding boost control (S150). In this case, it is not necessary to acquire the attitude angle information.

The spacecraft 100 may include a strain sensor or a distance sensor to detect the start of landing and the completion of landing.
The strain sensor is a sensor that measures the reaction force from the ground and is attached to each landing gear 101. The fall prevention control device 200 detects the start of landing and the completion of landing based on the reaction force measured by each strain sensor.
The distance sensor is a sensor that measures the distance to the ground, and is attached to the main body of the spacecraft 100 or each landing gear 101. The fall prevention control device 200 detects the start of landing and the completion of landing based on the distance measured by each distance sensor.

The fall prevention control device 200 may determine the magnitude of the injection amount of each thruster 102 based on the attitude angle information of the spacecraft 100.
For example, the determined injection amount increases as the inclination of the spacecraft 100 increases. Further, the determined injection amount is larger as the angular velocity toward the side where the spacecraft 100 is tilted is faster, and is smaller as the angular velocity toward the side opposite to the side where the spacecraft 100 is tilted is faster.

*** Effect of Embodiment 1 ***
According to the first embodiment, it is possible to prevent the spacecraft 100 from overturning at the time of landing even in a situation where the spacecraft 100 is likely to overturn at the time of landing as in the case where the spacecraft 100 lands on a celestial body with low gravity. It becomes.
When the gravity of the celestial body or the like on which the spacecraft 100 lands is very small, it is difficult to prevent the spacecraft 100 from tipping over at the time of landing by a method that relies only on a plurality of landing gears 101. However, since the fall prevention control device 200 controls the plurality of thrusters 102, the spacecraft 100 is prevented from falling during landing.

The fall prevention control device 200 executes attitude control (S140) or ground boost control (S150) after detecting the start of landing. This makes it possible to prevent erroneous control when none of the landing gears 101 are in contact with the ground.

The grounding boost control (S150) can prevent the spacecraft 100 from tipping over even when the attitude angle of the spacecraft 100 cannot be specified.
The grounding boost control (S150) enables a reliable landing regardless of the grounding condition, the attitude angle, the angular velocity, and the like.

Attitude control (S140) can accurately control a plurality of thrusters 102 to prevent the spacecraft 100 from tipping over.
Attitude control (S140) enables more reliable landing regardless of conditions such as ground contact conditions, attitude angles, and angular velocities.

*** Supplement to the embodiment ***
The embodiments are examples of preferred embodiments and are not intended to limit the technical scope of the invention. The embodiment may be partially implemented or may be implemented in combination with other embodiments. The procedure described using the flowchart or the like may be appropriately changed.

The "part" which is an element of the processing circuit 210 may be read as "processing" or "process".

100 spacecraft, 101 landing gear, 102 thruster, 109 solar cell paddle, 110 sensor group, 111 IMU, 112 STT, 190 spacecraft, 200 fall prevention control device, 210 processing circuit, 211 landing detection unit, 212 fall prevention control unit , 220 I / O interface.

Claims (9)

A spacecraft that lands on celestial bodies and conducts exploration.
With a plurality of thrusters attached to the spacecraft so that the direction opposite to the ground direction at the time of landing on the celestial body is the injection direction, and generating propulsive force toward the ground by injection at the time of landing on the celestial body. ,
A group of sensors that obtain attitude angle information of the spacecraft, and
A fall prevention control device that selects a part of the thrusters from the plurality of thrusters based on the attitude angle information obtained by the sensor group at the time of landing on the celestial body and causes only the selected thrusters to inject.
Spacecraft equipped with. The fall prevention control device identifies the attitude angle of the spacecraft in the inertial system based on the attitude angle information, converts the specified attitude angle into the attitude angle in the ground fixed coordinate system, and in the ground fixed coordinate system. The spacecraft according to claim 1, wherein some of the thrusters are selected based on the attitude angle. The exploration according to claim 2, wherein the fall prevention control device determines the presence or absence of a fall risk based on the attitude angle in the ground fixed coordinate system, and selects a part of the thrusters when it is determined that there is a fall risk. Machine. The attitude angle information includes the angular velocity of the spacecraft in the inertial frame.
The fall prevention control device converts the angular velocity included in the attitude angle information into an angular velocity in the ground fixed coordinate system, and adjusts the allowable range of the attitude angle of the spacecraft based on the angular velocity in the ground fixed coordinate system. The spacecraft according to claim 3, wherein it is determined that there is a fall risk when the attitude angle in the ground fixed coordinate system is not included in the adjusted allowable range. The time of landing on the celestial body is at each time point in the time zone from the start of landing on the celestial body to the completion of landing on the celestial body.
The sensor group includes a sensor for obtaining velocity information of the spacecraft.
The fall prevention control device has claims 1 to 4 that detect each of the time when the landing on the celestial body is started and the time when the landing on the celestial body is completed based on the velocity amount information obtained from the sensor group. The spacecraft according to any one of the above. The time of landing on the celestial body is at each time point in the time zone from the start of landing on the celestial body to the completion of landing on the celestial body.
The spacecraft according to any one of claims 1 to 4, wherein the spacecraft includes sensors for detecting each of the start of landing on the celestial body and the completion of landing on the celestial body. .. The fall prevention control device is
It is determined whether the correct attitude angle information can be obtained by the sensor group, and it is determined.
When the correct attitude angle information can be obtained by the sensor group, a part of the thrusters is selected based on the obtained correct attitude angle information, and the part of the thrusters are made to inject.
The spacecraft according to any one of claims 1 to 6, wherein when the correct attitude angle information cannot be obtained by the sensor group, all of the plurality of thrusters are made to inject. It is a fall prevention method to prevent the spacecraft landing on the celestial body from falling.
The spacecraft
A plurality of thrusters attached so that the direction opposite to the ground direction at the time of landing on the celestial body is the injection direction,
A group of sensors that obtain attitude angle information of the spacecraft, and
Equipped with a fall prevention control device,
When the sensor group lands on the celestial body, the attitude angle information of the spacecraft is obtained, and the sensor group obtains the attitude angle information of the spacecraft.
The fall prevention control device selects a part of the thrusters from the plurality of thrusters based on the obtained attitude angle information.
A fall prevention method in which some of the thrusters generate a propulsive force toward the ground by injection. It is a fall prevention control device to prevent the spacecraft landing on the celestial body from falling.
The spacecraft
With a plurality of thrusters attached to the spacecraft so that the direction opposite to the ground direction at the time of landing on the celestial body is the injection direction, and generating propulsive force toward the ground by injection at the time of landing on the celestial body. ,
A group of sensors that obtain attitude angle information of the spacecraft, and
The fall prevention control device is provided.
The fall prevention control device is
It is provided with a fall prevention control unit that selects a part of the thrusters from the plurality of thrusters based on the attitude angle information obtained by the sensor group at the time of landing on the celestial body and causes only some of the selected thrusters to inject. Fall prevention control device.

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