RU2676368C1 - Method of clearing orbit from space debris - Google Patents

Abstract

FIELD: cosmonautics; recycling and disposal of waste.SUBSTANCE: invention relates to methods and means for cleaning orbits of space debris, mainly spent stages (OS) of launch vehicles. Method includes the removal in the area of cleaning of the spacecraft-tug (SCT) (1) and autonomous docking module (ADM) (2) on cable (4). ADM (2) is joined to OS (3) and quenches the kinetic moment of the OS with its control motors (6). Kinetic moment of bundle (1)-(4)-(2)-(3) is extinguished by engines of SCT (1) and engines (6) of ADM. Tension of cable (4) when SS (3) and SCT (1) are tightened is supported by SCT (1) engines at the level specified by the strength condition. Descent of the SS into the recycling orbit is carried out by engines of SCT and ADM. Operating system is chosen to carry out the said operations for its removal with the available power and thrust-weight equipment of the SCT and the ADM.EFFECT: technical result consists in increasing the likelihood of successful operations for actively de-orbiting space debris objects.1 cl, 5 dwg, 1 tbl

Description

 The invention relates to rocket and space technology and can be used for active removal from working orbits of various bulky space debris, for example, spent stages of launch vehicles (OS), using maneuvering spacecraft to dock with these objects.

A known method of active descent from the orbits of the OS, implemented in the form of a device, for example, “A spacecraft for cleaning space from passive spacecraft and their fragments” RU No. 2141436 B64G 1/16.

The closest in its technical essence is the patent RU No. 2531679 B64G 1/16, based on the removal of the tug spacecraft (CAB) and the autonomous docking module (AFM) in the orbit area, intended for cleaning them from space debris objects, consecutive long-range and short-range guidance for docking and capturing objects and their descent into disposal orbits, the selection of a sequence of objects from those available in orbits for their descent into disposal orbits is carried out by sequentially comparing the value of criterion d I of each object supposed to be launched, for example, the probability of an object colliding with other space objects, in addition, the compensation of accumulated errors of the KAB motion parameters during previous maneuvers, as well as target designation systems are distributed between the KAB correcting pulses at the long-range guidance stage and the AFM in the homing section from the condition providing relative motion parameters of the spacecraft and the object at the beginning of the homing phase of the AFM, corresponding to the probability of docking and capture of the object not lower than the specified one.

The disadvantages of this technical solution include the following items.

1) As a rule, OSs are non-cooperative objects rotating at an angular speed that must be reset after docking with the AFM, i.e. stabilize the angular movement of the ligament "AFM + OS", using the propulsion system (ДУ) АСМ. The considered technical solution does not take into account the fact that the kinetic moment of the coupled “AFM + OS” coupling determined by the product of the inertia tensor of this system by the angular velocity vector must be such that the control moments developed by the AFM propulsion system can nullify it, given the limitation on control moments developed by the AFM propulsion system. Therefore, it is necessary to take into account the restriction on inertial mass and centering characteristics and kinematic parameters of motion around the center of mass of the OS, selected as a candidate object for descent from orbit.

2) The limiting time of stabilization of the rigid AFM + OS system using the AFM propulsion system, which should be such that the angle of rotation of the rigid AFM + OS system in each stabilization channel at the stabilization stage does not exceed a predetermined value determined by the relative position, is not taken into account system "AFM + OS", KAB and the position of the cable.

3) The possibility of increasing the angular velocity of the bundle “KAB + cable + AFM + ACM” at the stage of approaching “AFM + OS” and the KAB with the help of a cable system, caused by the initial relative motion of the centers of mass of the OS and the KAB, and the corresponding increase in the cable tension, which may exceed its strength.

4) The requirements for stability and controllability of the KAB + AFM + OS system at the descent stage with the help of the KAB propulsion system, which imposes restrictions on the inertial mass and centering characteristics of the OS, and the KAB propulsion system, are not taken into account.

5) The possibility of using the AFM at the stage of descent of the propulsion system in case of a lack of control moments of the CAB is not taken into account.

The aim of the proposed technical solution is to eliminate these drawbacks of the prototype, which is achieved by the fact that in a known method based on the removal of the spacecraft and AFM in the field of orbits designed to clean them from objects of space debris, successive maneuvers of far and near guidance for docking and capturing objects and their descent into orbits of utilization, the selection of a sequence of objects from those available in orbits for their descent into orbits of utilization, is carried out by sequential comparison of the value of the criterion I, for each object that is supposed to be launched, the distribution of compensation for accumulated errors of the KAB motion parameters during previous maneuvers, as well as the target designation system, between the correcting pulses of the KAB at the stage of long-range guidance and the AFM in the homing section from the condition of providing relative parameters of motion of the KAB and the object at the beginning of the homing stage AFM, the following additional steps are introduced.

OS selection is carried out from the following additional conditions:

1) the OS kinetic moment must not exceed a predetermined value determined by the control moment of the AFM propulsion system and a predetermined time to zero this kinetic moment;

2) the kinetic moment of the system "CAB + cable + AFM + OS" in the area of tightening and braking rotation should not exceed the specified values determined by the control moments of the propulsion systems AFM and CAB;

3) with an increase in the cable tension force to critical values, the KAB propulsion system is activated, the traction force of which is directed against the tension force acting on the cable to reduce its level to permissible values;

4) the motion control of the “KAB + AFM + OS” system during the maneuver of launching into the orbit of disposal is carried out using propulsion systems KAB and AFM.

The implementation of the method

The essence of the proposed method is illustrated by the diagrams presented in the figures, where

in FIG. 1 shows the individual objects KAB - 1, AFM - 2, OS - 3, cable - 4;

in FIG. 2 - system "AFM + OS" on a cable connection with CAB 1;

in FIG. 3 - system "KAB + AFM + OS";

in FIG. 4 - the process of tightening the CAB and "AFM + OS" using a cable;

in FIG. 5 - the process of stabilization of the AFM + OS system due to the application of rods by the chambers of the AFM propulsion system when pulling together with the KAB.

1) Limit on the kinetic moment of the OS.

перпендикулярной плоскости фиг. 2) уравнение углового движения (уравнение Эйлера) можно записать в виде:Suppose that the angular velocity of the OS along the axes ω_x3, ω_y3, ω_z3 are small, so that the terms containing their product can be neglected, then the angular motion in each channel can be considered independently. For example, in the yaw channel (rotation around axis axis

perpendicular to the plane of FIG. 2) the equation of angular motion (Euler equation) can be written in the form:

- момент инерции системы «АСМ+ОС» относительно оси

, проходящей через ее центр масс 5,

- угловое ускорение в канале рыскания,

- управляющий момент в канале рыскания органов управления АСМ относительно центра масс 5 системы «АСМ+ОС». Знак минус в правой части показывает, что управляющий момент уменьшает угловую скорость «АСМ+ОС». Предполагается, что трос не оказывает влияние на движение системы «АСМ+ОС». В начальный момент времени угловая скорость системы:Where

- moment of inertia of the AFM + OS system relative to the axis

passing through its center of mass 5,

- angular acceleration in the yaw channel,

- control moment in the yaw channel of the AFM controls relative to the center of mass 5 of the AFM + OS system. The minus sign on the right side indicates that the control moment reduces the angular velocity of “AFM + OS”. It is assumed that the cable does not affect the movement of the AFM + OS system. At the initial time, the angular velocity of the system:

измеряется бортовой аппаратурой АСМ. Управляющий момент в канале рыскания органов управления АСМ определяется выражением:The initial value of the angular velocity of the system at the time of the start of braking (t = 0) for zeroing the kinetic moment is

measured by onboard AFM equipment. The control moment in the yaw channel of the AFM controls is determined by the expression:

- тяга двигателя 6 АСМ в канале рыскания,

- плечо управляющего момента относительно центра масс системы «АСМ+ОС».Where:

- thrust of the engine 6 AFM in the yaw channel,

- the arm of the control moment relative to the center of mass of the AFM + OS system.

и угла ϑ получаются в результате интегрирования уравнения (1) на интервале времени работы двигателей АСМ - от t₀=0 до t_К=Т:Expression for angular velocity

and angle ϑ are obtained by integrating equation (1) over the time interval of the operation of the AFM engines - from t ₀ = 0 to t _K = T:

where: ϑ ₀ are the values of the initial yaw angle of the “AFM + OS” system at the time the engines start working. After the work of the AFM control unit, the following condition must be satisfied:

and the restriction on the change in the angular position of the AFM + OS system from the angular position of the AFM at the time the kinetic moment is zeroed should not be more than Δϑ _back :

Expressing from (5) the time of zeroing of the kinetic moment, taking into account (3), we obtain:

Condition (6) takes the form

or

кг⋅м² плечом управляющего момента относительно центра масс системы «АСМ+ОС»

м, тягой ДУ

Н и Δϑ_зад=π/2:For example, for a bunch (OS + AFM) with a total moment of inertia

kg⋅m ^{2 by the} arm of the control moment relative to the center of mass of the AFM + OS system

m, thrust remote control

H and Δϑ _ass = π / 2:

Orientation engines used on upper stages and spacecraft (SC), as a rule, have a small thrust, therefore, the obtained value of the limiting angular velocity (10) is small. Considering the tasks assigned to the AFM, it is advisable to use greater thrust control to control the angular movement.

As follows from conditions (6) - (8), the parameters of the process of zeroing the kinetic moment of the system (AFM + OS) are determined:

- parameters of the propulsion system and design of the AFM;

- moment-centering characteristics of the OS and AFM;

- an allowable change in the angular position of the AFM + OS system until its angular velocity is zeroed.

2) Limitations on the kinematic parameters of the relative motion of the KAB and “AFM + OS”.

Due to the relative motion of the centers of mass of the ACS objects and the “AFM + OS” ligament (Fig. 4), since the “ACL + ACM” and OS moved before their docking in their orbits (items 7 and 8 of Fig. 4), after the docking and of the formation of the “AFM + OS” bond, the “KAB + cable + AFM + OS” system will rotate around the common center of mass 9 with an angular velocity ω _c0 . The angular velocity will increase with decreasing cable length due to the law of conservation of kinetic momentum. For example, when a AFM and a spacecraft moving in an elliptical orbit h _1p × h _{1 a are connected} with an OS moving in the same plane in a circular orbit with a height h _{3 a} = h _{l a} , the speed difference at the common point of two orbits will be determined by the expression ¹ ( ¹ Sukhanov A.A. Astrodynamics / A.A. Sukhanov - M .: Space Research Institute RAS, 2010):

where r ₃ = p ₃ = r _{1 a} is the radius of the orbit of the OS and the radius of the apogee of the KAB, μ = 3.986⋅10 ⁵ km ³ / s ² is the gravitational constant of the Earth, p ₃ is the focal parameter of the orbit of the KAB, e is the eccentricity of the orbit of the KAB e = (r _{1 a} -r _1p ) / (r _{1 a} + r _1p ), r _1p is the perigee radius of the KAB orbit. For h _a = 900 km, h _p = 600 km, the speed difference (11) reaches 78 m / s.

The initial angular velocity of the bundle "KAB + cable + AFM + OS" will be determined by the expression:

- начальное расстояние между центрами масс КАБ и АСМ с ОС, определяемое длиной троса

, где d₁ - расстояние от центра масс КАБ 12 до точки закрепления 10 троса на КАБ, d₃ - расстояние от центра масс 5 связки АСМ и ОС до точки закрепления 11 троса на АСМ. Для

км начальная угловая скорость (12) будет равна:Where

- the initial distance between the centers of mass of the KAB and AFM with OS, determined by the length of the cable

where d ₁ is the distance from the center of mass of the cable 12 to the point of attachment of the cable 10 to the cable, d ₃ is the distance from the center of mass 5 of the AFM and OS bundles to the point of attachment 11 of the cable to the cable. For

km initial angular velocity (12) will be equal to:

The sheaf “KAB + cable + OS + AFM” will rotate around a common center of mass 9. The initial moment of inertia of the sheaf as a system of material points (excluding the intrinsic moments of inertia of bodies) relative to the center of mass of the sheaf “KAB + cable + OS + AFM” will be determined expression ² ( ² Markeev A.P. Theoretical mechanics: Textbook for universities. - M.: Regular and chaotic dynamics, 1999):

where m is the reduced mass of the bundle "KAB + cable + AFM + OS":

- расстояние от центра масс 9 связки «КАБ+трос+АСМ+ОС» до центра масс КАБ 12,

- расстояние от центра масс 9 связки «КАБ+трос+АСМ+ОС» до центра масс 5 связки АСМ с ОС. Выражение для кинетического момента связки «КАБ+трос+ОС+АСМ» относительно ее центра масс после стыковки будет иметь вид² (² Маркеев А.П. Теоретическая механика: Учебник для университетов. - М.: Регулярная и хаотическая динамика, 1999):

- the distance from the center of mass 9 of the bundle "KAB + cable + AFM + OS" to the center of mass of KAB 12,

- the distance from the center of mass of 9 bundles "KAB + cable + AFM + OS" to the center of mass of 5 bundles of AFM with OS. The expression for the kinetic moment of the “KAB + cable + OS + AFM” sheaf relative to its center of mass after joining will be ² ( ² Markeev A.P. Theoretical Mechanics: Textbook for Universities. - M .: Regular and chaotic dynamics, 1999):

In accordance with the law of conservation of the kinetic moment of the system:

угловая скорость будет равна:as the length of the cable decreases, the moment of inertia of the bundle (J) will decrease, and the angular velocity will increase. With cable length

angular velocity will be equal to:

и АСМ -

(фиг. 4). Силы, создаваемые двигательными установками управления угловым движением КАБ и АСМ, должны лежать в одной плоскости и направлены в противоположные стороны, создавая момент относительно центра масс связки, противоположный направлению вращения связки.The module of the kinetic moment of the “KAB + cable + AFM + OS” system, after its formation and before the KAB is connected to the AFM and OS, must be reduced using the motor settings for controlling the angular motion of the KAB -

and AFM -

(Fig. 4). The forces created by the motor units for controlling the angular motion of the KAB and the AFM should lie in the same plane and directed in opposite directions, creating a moment relative to the center of mass of the ligament, opposite to the direction of rotation of the ligament.

(фиг. 4). Влиянием

на движение центра масс связки пренебрегаем. Одновременно с уменьшением угловой скорости связки уменьшается длина троса. Предположим, что расстояние между центрами масс КАБ 12 и связки АСМ с ОС 5 уменьшается по линейному закону:3) We determine the traction force necessary to damp the angular velocity of the cable system. For simplicity, we assume that the angular velocity of the cable system decreases only due to the action of the AFM traction force -

(Fig. 4). Influence

neglect the motion of the center of mass of the ligament. Simultaneously with a decrease in the angular velocity of the bundle, the cable length decreases. Suppose that the distance between the centers of mass of KAB 12 and the AFM ligament with OS 5 decreases linearly:

where k is the rate of change of cable length.

The theorem on the change in the kinetic moment of a system consisting of two material points with masses m _AFM + m _OS and m _CAB , connected by a cable and rotating around a common center of mass will have the form:

The moment of inertia of the cable systems relative to its center of mass is determined as follows

Substituting (20) into (19), denoting m ₃ = (m _AFM + m _OS ), we obtain the following differential equation:

or

, необходимую для гашения угловой скорости тросовой системы при выбранном законе изменения длины троса:Integrating equation (22), we obtain the thrust estimate

necessary to damp the angular velocity of the cable system with the selected law of change in cable length:

. При массе КАБ=1000 кг, массы ОС с АСМ m_АСМ+m_ОС=4000 кг, начальной угловой скорости тросовой системы ω₀=10°/с,

м,

м и t_k=500 с, тяга АСМ должна бытьWhere

. With mass KAB = 1000 kg, mass of OS with AFM m _AFM + m _OS = 4000 kg, initial angular velocity of the cable system ω ₀ = 10 ° / s,

m

m and t _k = 500 s, the thrust of the AFM should be

будет создавать момент относительно центра масс связки АСМ и ОС, что приведет к увеличению угла Δϑ между продольной осью АСМ и линией троса (фиг. 4) и снижению эффективности гашения угловой скорости тросовой системы, вследствие изменения направления силы

по отношению к тросу.Force

will create a moment relative to the center of mass of the bundle of the AFM and the OS, which will lead to an increase in the angle Δϑ between the longitudinal axis of the AFM and the cable line (Fig. 4) and a decrease in the efficiency of damping the angular velocity of the cable system due to a change in the direction of the force

in relation to the cable.

на относительное движение троса и связки АСМ с ОС (или КАБ, если для гашения угловой скорости тросовой системы используется ДУ КАБ) может быть компенсировано моментом создаваемыми двигателями ориентации АСМ -

13 (фиг. 5). Тяга

будет зависеть от угла между линией троса и продольной осью АСМ и от силы натяжения троса Т. Предполагая малость углового ускорения тросовой системы, из условия равенства нулю суммы моментов от силы натяжения троса, силы

и сил двигателей ориентации 13:Force action

the relative movement of the cable and the AFM bundle with the OS (or KAB, if the KAB remote control is used to damp the angular velocity of the cable system) can be compensated by the moment created by the AFM orientation engines -

13 (Fig. 5). Thrust

will depend on the angle between the line of the cable and the longitudinal axis of the AFM and on the tension of the cable T. Assuming that the angular acceleration of the cable system is small, from the condition that the sum of the moments on the cable tension and the force equal to zero

and forces of orientation engines 13:

The angular speed of rotation of the bundle of KAB and AFM with OS on a cable connection around a common center of mass 9 leads to the appearance of a tensile force T in the cable 4 (Fig. 5), which should not exceed the limit value determined by the strength characteristics of the cable and its attachment points on the KAB 10 and AFM 11.

Consider the motion of the CAB around the center of mass of the cable system. KAB moves around a circle of radius

.

.

Centripetal acceleration of the CAB equal to the product of the square of the angular velocity of the cable system and the distance from its center of mass 9 to the center of mass of CAB ³ ( ³ Markeev A.P. Theoretical mechanics: Textbook for universities. - M.: Regular and chaotic dynamics, 1999) 12 ( Fig. 5) is created by the cable tension force T, which is equal to the product of the centripetal acceleration of the cable and its mass:

For a cable with a cross-sectional area S made of a material with a known ultimate stress [σ], the angular velocity of the bundle around the center of mass should not exceed the value:

To reduce the tension force of the cable, the KAB main (marching) engine can be used, creating a thrust F _KAB (Fig. 5), directed along the line of the cable. The acceleration of the CAB created by the cable tension force can be reduced by the value of the acceleration created by the CAB remote control:

,

,

in this case, the total acceleration will be equal to the centripetal acceleration during the motion of the CAB around the center of mass of the ligament 9 (Fig. 5).

Taking into account the action of the KAB engine, condition (27) will take the form:

For example, with a total mass of AFM and OS m _AFM + m _OS = 4000 kg, weight KAB m _KAB = 1000 kg, engine traction KAB F _KAB = 3000 N, the angular velocity of the system with a cable with a diameter of 4 mm from a material with [σ] = 3 GPa (cable made of Spectra-1000 material with a density of 0.97 g / cm ³ ) and a length of 1 km should be no more than:

4) The capabilities of the KAB propulsion system to ensure the stability and controllability of the “KAB + ASM + OS” system when implementing a maneuver for transition to the descent orbit.

It is assumed that the location of the objects KAB, AFM, OS in the system "KAB + AFM + OS" corresponds to FIG. 3 poses 1, 2, 3: the longitudinal axes of all objects and the centers of mass are located on the common longitudinal axis of the “KAB + AFM + OS” system (pos. 14, Fig. 3), and the directions of the axes associated with the AFM coordinate system coincide with the direction of the connected axes of the KAB , i.e. KAB control moments coincide with AFM control moments.

Due to the possible appearance of disturbing moments due to:

- the appearance of the displacement of the center of mass of the system "CAB + AFM + OS" (pos. 15, Fig. 3) in the transverse plane;

- the presence of residual liquid fuel in the tanks of the OS, etc.,

it is necessary to ensure the conditions for controllability and quality of the stabilization process, respectively, the accuracy of working out the impulse for maneuvering the descent of the KAB propulsion system, due to the KAB - M _F control moments. The condition must be met:

For traction of the main engine KAB F _KAB = 3000 N and the maximum displacement of the center of mass of the system δ = 0.05 m, the total moment M _F created by the orientation engines must be at least 150 N⋅m, which corresponds to 3 to 4 m on the arm h traction F _KAB from 38 to 50 N.

.As noted above, the orientation engines used on the currently existing acceleration blocks (RB), as a rule, have less traction and are not designed to parry disturbances of this level (table 1), therefore, the motion control "KAB + AFM + OS" is proposed to carry out at the expense of the KAB propulsion system (marching and steering nozzles of orientation and stabilization) and additional use of the propulsion system and the AFM control system -

.

Using the proposed technical solution will allow you to choose the OS, taking into account not only the criteria for the danger of collision with other space objects, but also taking into account the capabilities of the spacecraft, AFM.

Claims (1)

A method for cleaning orbits of space debris objects, based on the removal of a spacecraft-tug (KAB) and an autonomous docking module (AFM) in the region of orbits intended for their cleaning from objects of space debris, for example, spent stages of launch vehicles (OS), sequential maneuvers far and near guidance for docking and capturing the OS and their descent into disposal orbits, selecting the OS sequence by sequentially comparing the criterion value for each proposed OS, for example, the probability of contacts of the OS with other space objects, characterized in that the OS is additionally selected from the conditions so that the OS kinetic moment does not exceed a predetermined value determined by the control moment of the AFM propulsion system and a given time to zero this kinetic moment, and the kinetic moment of the KAB + cable + AFM + OS in the area of contraction and braking of rotation did not exceed the specified values determined by the control moments of the ACM and KAB propulsion systems, ensuring its zeroing, while The ligament is tensioned using the AFM propulsion system, while increasing the cable tension force to critical values, a longitudinal impulse of the KAB propulsion system is applied, directed against the tension force, until it decreases to a value determined by the cable strength, motion control of the KAB + AFM + OS system during the descent maneuver into orbit of disposal is carried out using propulsion systems KAB and AFM.

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