DE102007041994B4 - Mechanism for ejecting a shock mass for deflecting an interfering satellite to a tolerable orbit by collision - Google Patents

Abstract

An apparatus which is an auxiliary satellite containing a drive means for pushing a shock mass towards a trajectory towards a target satellite with subsequent impact contact to butt these disused and interfering target satellites, without disassembling it, into a tolerable trajectory

Description

The The invention relates to a mechanism for ejecting a shock mass for Distraction of a disturbing Satellites on a tolerable pathway through a collision.

Everyone Satellite has a certain lifespan in orbit. He can as a result Malfunction will be irreparable. Every interfering satellite would have to be in the future be brought to a tolerable track.

at low train height he loses in the still functional Condition at low train heights Stopping through the atmosphere at height as well as for other reasons the functionally required position and orientation. Last Because of fuel shortage, he can no longer reach the operating altitude as well to the adequate Orientation of the situation can be brought, whereby he then as space scrap or space debris is, so there is a risk of collision with other satellites. It comes then after a relatively long time to an almost complete burnout in the The atmosphere.. The remaining debris reaching the earth should do minimal damage can do. Then a supportive downward or horizontal braking pulse, too lead to a faster descent with a more effective incandescence process.

Remains a non-functioning geostationary satellite (orbital high) in orbit, insists for later same position over satellites to be placed on the ground the risk of a collision, so the loss. Such useless as space debris to be regarded Satellites would have to be transported to a relatively high orbit. So they the tracks other later Do not compromise satellites, the each new train should be designed so that it as possible remains stable for a long time.

The geostationary Satellites are already designed to end at the end of estimated life with a residual fuel amount to one about 100 km higher Railway can be lifted referred to as "graveyard orbit = Orbital Cemetery ". The necessary Residual fuel for reduced the momentum from the last engine thrust due to limited correction possibilities the active life of the satellite. Should this residual fuel about because Engine failure can no longer be used, eliminating this possibility of railway lift.

Out energetic reasons it is impossible, the target satellites by an impulse to escape velocity and thus to bring to a parabolic railway. If that succeeds, you would have the greatest security achieved, because you would have then a return to him Earth impossible made.

Out The prior art discloses various proposals for solving this problem.

Except for exceptions ( DE 694 25 730 T2 . US Pat. No. 6,655,637 B1 ) is common to all proposals that catching objects in space are recovered and then treated.

The DE 103 42 954 A1 shows an auxiliary satellite firing a net towards the target satellite that encloses it. After closing the net opening the target satellite is pulled with a rope to the auxiliary satellites.

The US 4 750 692 A represents a with the help of compressed air pushed out to the outside gripper system, which can catch and recover by means of folding arms, bola-like safety ropes and Velcro strips (velcro strips) in particular target satellites with spin.

The US 5 279 482 A is used for self-rescue of astronauts in the outboard deployment. Specially designed Bola balls are thrown by the astronaut in the direction of suitable spaceship structures. With a firm hold after wrapping, the astronaut pulls himself to safety.

The DE 100 59 914 A1 shows an auxiliary satellite with an extendable telescopic mast, the adapter half can engage in that of the target satellites. By winding a rope salvage on the auxiliary satellites takes place.

The DE 694 25 730 T2 deals with an autonomous extension craft containing a command module with a docking adapter ring. The extension spacecraft connects with an adequate adapter ring of the target satellite to this. Thereafter, a path change of the overall configuration by means of thrusters. The new orbit may be a pay orbit (continue to use target satellite) or an elimination orbit (glitter or grave yard orbit). The control is done manually.

The US Pat. No. 6,655,637 B1 handles a helper satellite that attaches to the target object. The gripper mechanism consists of pressure gas inflatable fingers. These are curved out of the stretched position via sensor-controlled pull ropes and pressed firmly against the target object. An elimination of the target object by transfer into an elimination orbit can be done by an inflatable balloon (on Verglühbahn by atmospheric braking), solar panels by radiation pressure of the sun (on Grave Yard orbit), as well as by thrusters of the auxiliary satellite, but also a new Nutzorbit can produce.

A disadvantage of these known solutions is:
Only the salvage of the target satellite will be given priority and only a subordinate reference to a deorbitation of an object (target satellite) that is to be eliminated (not to be destroyed). Only at DE 694 25 730 T2 . US Pat. No. 6,655,637 B1 the deorbitation can be considered relevant.

Most of time are also complicated and costly processes in salvaging necessary.

The use of ropes, nets, tentacles and bolas ( DE 103 42 954 A1 . US 4 750 692 A . US 5 279 482 A ) reduces the security to hit or secure the target satellite.

The at US 4 750 692 A proposed Velcro or velcro tape is in two parts (loop and hook part). Even with a complete occupancy of the parts to be combined with the necessary tapes, a secure connection from the proposed winding movement is problematic, with the adhesive connections must be noted.

The at DE 100 59 914 A1 and DE 694 25 730 T2 used coupling adapters allow a secure coupling when the objects are combined and locked after usual approach maneuvers. However, they exclude all target satellites that do not have such a coupling adapter half.

task This application is therefore to provide a device which mechanically simple and thus cost-effective way without prior Salvage brings a target satellite into an elimination orbit, at that by previous thorough Analysis has shown that it can no longer be used.

The The object is achieved with a device according to the features of the claim 9 solved.

To it is proposed that for a track change of the satellite to be removed (target satellite) required impulse represented by a shock pulse. By an approximately radially outward (at geostationary Satellites) or inside (low-flying satellites) shock, caused by a shock mass, the target satellite is brought to a tolerable track.

One Auxiliary satellite comprises a device for spinning a mass, the hanging on a robotic arm Impact mass, on the target satellites, which is to be brought on suitable track.

Around the position and position of the shooting auxiliary satellite as possible will change little a device that uses the reactions (forces, moments) largely compensates. This is done by another robotic arm attached countermass.

The Countermass moves on geostationary target satellites Downhill course, in those with low orbit height but on an ascent So exactly opposite to the shock mass.

she always provides an extra disturbing mass in space

you So she should make her disappear. It is therefore proposed to build them from dry ice, to compact the carbon dioxide snow Masses is squeezed. Set immediately after launch this ice by ejecting from the pressurized encapsulation of the space environment, it goes through sublimation directly in the vaporous state. A risk of collision, caused by the countermass is thus no longer given.

compensation The response to the auxiliary satellite is achieved by: two oppositely coupled by an intermediate gear drive motors rotate, which drive the two masses. In addition, adequate balancing weights are equal on separate robot arms, the centrifugal effects of impact and countermass out.

are the desired Circulation speed and firing position reached done simultaneously from the same position the kills of the shock and countermass. For this purpose, pressure springs acting in the direction of flight of the masses are additionally relaxed.

The impact mass thus meets with a radially outward / inward speed on the target satellites. She should get out of his way outside / inside to press, that he describes a high / low elliptical orbit that goes up not disturbing other satellites acts.

Of the Shock can either inelastic or plastic. In the inelastic Case separates the shock mass after that more or less of the target satellite, d. H. she is pushed back and follows absolutely considered him.

The elastic case with shock energy loss zero at maximum speeds of the masses involved after the impact is not feasible. Inevitable is a shock loss, referred to as inelastic case, although elasticity is present. In the realizable plastic case, however, target satellite and shock mass remain together thereafter. Either then the impact mass is plastic or the two bodies remain after an inelastic Collision due to interlocking the structural structures of target satellite and shock mass together.

It comes then after the mass shedding to a deceleration of the rotating Masses down to zero.

To the drive motors are in braking circuit and additionally two on the two engine shafts acting (not shown) disc brakes used. Thus, the process remains free of reaction even in this phase.

The invention will be described below with reference to the drawings (in which 1 to 15 ) explained in more detail.

In the 1 If the target satellite is a geo-stationary or geo-synchronous satellite on a circular path in the equatorial plane at a specific geographic length, the z. B. the nominal target height (position) or orientation of the situation can not comply because he z. B. is no longer correctable due to fuel shortage or system failure.

The impact mass is with the associated robotic arm with time and direction with appropriate impulse to the target satellites thrown upward. The latter should not by the shock in ruins disassembled but only brought to a higher orbit height become.

The Counterweight attached to another robotic arm will be in the discharge time the shock mass flung down in exactly the opposite direction.

The Indian 2 The process represented is approximately the inverse of the 1 The LEO railways are subject to the braking influence of the earth's atmosphere, especially at low railway heights, so that they finally have a permanent downward trend.

The needed Energy to dislodge such a target satellite is quite high. The reason is because of the higher speed too higher kinetic energy. However, the braking effect favors the earth's atmosphere especially then a quick descent, if not too large satellite masses one possible greater Satellite cross-section is present (large ballistic factor).

Consequently can be expected that after successful impact of the impact mass on the target satellites this burned up after a few months in the earth's atmosphere. Of the Impact time and location of any remaining Debris can be more accurate determined and necessary precautions are taken.

The 3 shows how after unfolding the leaf springs from the storage arrangement (s. 4 ) out into the work arrangement a torus-like structure arises. In this case, then old masses are evenly distributed on the circumference in a plane. Before that, however, the compact impact mass (in a jam arrangement) must be moved out of the stowed position into the satellite center plane (x, y) into the operational position by its robot arm.

It becomes a torus-like Deployed from the primary star (LI to LIV) and the on the z-axis offset secondary star (RI to RIV) exists. The intermediate links ZI to ZIV connect the segments of both Stars arranged in two different levels and complete she. Each star thus consists of the segments I to IV with theirs Mid-MI to MIV. Before the shock will the primary star moved axially into a common front with the secondary star, so that a uniform impact level forms.

Around effective shock pulses transferred to, is a correspondingly large impact mass required. Therefore, all leaf or bending springs are complete (Z) or partially (L, R) with heavy additional masses.

These have to be arranged so that they do not have the variable bending ability of the leaf springs hinder. The distribution of the additional masses must therefore allow it to no impairment of Leaf springs comes. The outward towards decreasing radii of curvature have to so remain feasible. The additional masses should be compact but light be deformable. Thus, there is a heavy grainy, but resistant to environmental influences Material on.

The 4 It is important that the entire leaf spring structure for transport into orbit in the rocket stage, ie within the Enveloppe, can be accommodated. The envelope circle in the (x, y) plane is shown in dot-dash lines. It follows that the segment of the dot-dashed secondary star RI is not to be accommodated in an (x, y) plane in addition to the primary star, so an offset in z is essential. Otherwise, there would be no space for the other segments.

The relaxation or deployment of the bending springs LI to LIV from the storage arrangement out into the working arrangement ( 3 ) is generated by clockwise rotation (-z), that of the torsion springs RI to RIV by left rotation (+ z) of the corresponding hubs. The torques are moved in opposite directions Hollow hubs to which the leaf springs are hinged generated. From a relaxation is finally an oppositely directed clamping, so that the leaf springs are turned outward and are under tension. In each case, a preloaded leg spring is provided per leaf spring at the connection point.

By means of 5 the unfolding process of the primary star P and the secondary star S is represented by a segment. A segment consists of a left leaf spring of the primary star and a right of the secondary star and an associated intermediate spring Z. In this view, the primary lies behind the secondary star. Opposite rotations θL and θR are carried out by hubs NP and NS with spring bases connected by two motors. From the stowed position (t1), the leaf springs are slipped into the unfolded position (t3). via the dashed intermediate position (t2). Recognizable is the exact radial wandering of the intermediate spring Z to the outside. This process is supported by relieving the preloaded torsion springs with spring travel ηL and ηR attached to each leaf spring base.

The 6 represents on a (tripartite) segment how the formation of a uniform abutment surface takes place. For this purpose, the primary star P is brought into a front with the secondary star S with respect to the abutment surface directed towards the target satellite. This is made possible on the one hand by axial displacement (under tension spring force) from P to S by the amount a in the direction -z. On the other hand, the intermediate member Z is rotatable about the pivot point A because of a slot LL in the fork. A waiver of this orientation would mean a rugged impact surface. In order to achieve a central shock, then incalculable disturbances would come into play, which must be avoided so as not to impair the impact effect.

robot arms

7 to 10 : The discharge masses mS and mG and the diametrically arranged balancing masses mAR and mAr assigned to them are accommodated during the transfer to orbit in the so-called congestion arrangement within the last rocket stage. Geometric constraints are given by the rocket-dependent envelope.

Adjustment of primary and secondary star

During the unfolding of the leaf springs opposing rotations of the two stars are required. Because both stars have a tension spring 7 are supported by four thrust bearings 12 (Needle bearing) in 1 on the tread of the mating ring 14 in 2 from.

After unfolding of all leaf springs 3 the Stars 1 and 2 from the stowage arrangement to the operational arrangement, with the torsion springs 4 under supportive, is still the production of a common abutment area required. The primary star 1 is on the central bolt firmly connected with H 6 over ball circulation shoe 8th mounted longitudinally displaceable. The secondary star 2 is in the receiving neck 5 stored by H. On the other hand, he relies on 8th as well as over radial bearings 10 on the primary star 1 from.

In order to achieve the most accurate, error-free central shock, the primary star impact surface must first be brought into conformity with the secondary star impact surface, so that a common as little as possible rugged impact surface is present. This requires an initialization. After unfolding (sensor-controlled) of all leaf springs, the initialization takes place for axial adjustment. For this purpose (radio-controlled) four pyrotechnic igniters (not shown) are triggered. These generate radially outward forces 13 , which consists of the four-segment counter-ring 14 blow away. Because the four needle bearings 12 no tread found, is by means of the tension spring 7 that on 1 such as 6 is attached, the primary star pulled to the right (-z). The four recesses ( 11 ) in the hub of 2 allow the necessary for this axial offset mutual nesting. In the end position prevents engagement of both halves of the gear coupling 9 a mutual rotation about the z-axis.

Aggregate for clamping the shock mass

The 13 shows the articulated on the robot arm drive unit for the clamping unit of the shock mass. The tensioning unit ensures the unfolding or relaxing and then re-tensioning the leaf springs to the torus-shaped shock mass. The unit includes two counter-rotating electric motors 1 and the spur gear pairs 2 to 4 translated with i = 1. Pair 4 serves only to synchronize both counter-rotating drive shafts 5 and 6 for the stars 7 and 8.

The Reaction torques of the motors as well as the bearing forces balance each other completely. Only the moments from the bearing forces are not completely balanced. They are over The robotic arm is initiated at the auxiliary satellites and must be replaced by the Position control system can be compensated.

Aggregate for skidding the Robotic arms of shock and countermass

The 14 shows the elements of the drive unit for the robot arms. The arms generate for the shock and countermass as well as their compensation Mass the skidding movement.

Available are the opposite working e-motors 1 and with i = 1 translated spur 2 to 4. pair 4 serves only the synchronization of both drive shafts 5 and 6 for the four robot arms. The indices A and B stand for the shock and the To ground.

at the center-symmetrically selected to the z-axis arrangement corresponding to each other Elements are all alike Reactions (moments, powers) Completely out.

dry ice

Corresponding 15 is proposed because of the special sublimation dry ice for the countermass. This peculiarity of carbonic acid is due to the location of the triple point, ie those value pairs of pressure and temperature at which the vapor, liquid and solid phases are in thermodynamic equilibrium.

Carbon dioxide snow can by throttling mixed liquid and vapor CO2 be won. By pressing into blocks this results in the compact Dry ice with a density of approx. 1.5 kg / liter.

Opposite water ice At 0.9 kg / liter, dry ice has a much higher density. For the Countermass is to form a cylindrical mass. This will be in hermetically enclosed in a pressurized capsule. through Pyrotechnics, the capsule is blown away after repelling. Then The dry ice is immediately exposed to the low ambient pressure while the Ambient temperature earlier has been achieved.

For the LEO case, the railway height was assumed to be 500 km:
Pressure about 1.E-11 at
Temperature about -73 gr. C

Around to ensure the solid phase safely At the relatively high temperature, a pressurization of at least 3 at proposed. higher Pressure would be to delimit from the vaporous Phase better.

In the GEO case with the railway altitude 35786 km, it was assumed:
Pressure about 1 E-20 at
Temperature about -269 grd C

A Pressurization of the dry ice can be lower here as in the LEO case.

To Blasting away the capsule is always an isothermal state change from A to B. Because of the extremely low ambient pressure occurs Sublimation from the solid to the vaporous state. The balance curves show that for LEO and GEO are each the starting point A to the left of the triple point. Here the curve "solid vapor" is extreme low temperatures and pressures extrapolated.

GEO

Geo-stationary orbit or Geo-synchronous Earth orbit at a railway altitude of 35786 km

LEO

low Earth orbit (railway heights up to 1000 km) indices:

R

for the rotating System in the target satellites

I

for the inertial System in the center of the earth

Z

Target satellite, passive or disturbing

H

Auxiliary satellite, active or operational

mS

impact mass

mG

to ground

ωS

rotation speed the swivel arm of the shock mass

ωG

rotation speed the swing arm of the counterweight

e

enveloppe (enveloping Cylinder jacket of defined length) indicates payload volume within rocket stage in terms of complete auxiliary satellites

mAR

Leveling compound to the shock mass mS, diametrically to lever arm R

mAr

Leveling compound to the counterweight mG, diametrically to the lever arm r

1

primary star

2

secondary star

3

leaf spring

4

Leg spring

5

receiving socket at auxiliary satellite H for secondary star

6

central bolt at the auxiliary satellite H for primary star

7

mainspring

8th

Linear recirculating ball bearing

9

gear coupling

10

radial bearings

11

Recess in hub of 2 to the axial displacement of 1

12

needle roller bearings for axial force absorption

13

force directions after triggering the pyrotechnic detonator

14

Counter ring as a running surface of the needle roller bearings 12

15

opposing electric motors

16

Spur gears (i = 1)

17

Spur gears (i = 1)

18

Spur gears (i = 1)

19

output shaft for primary star or impact mass

20

output shaft for secondary star or to ground

Claims (10)

Device that represents an auxiliary satellite that includes a drive device to push off one impact mass on a trajectory in the direction of a target satellite with subsequent impact contact, around this disused and disturbing Target satellites, without disassembling it into parts, to a tolerable To hit the track Device according to claim 1, characterized in that in that the drive device has a robot arm for initiating a transfer path of the impact mass, on which these purposefully thrown away by the rotating robot arm becomes Device according to claim 2, characterized in that that the drive device continues to rotate in opposite directions exactly defined robot arm contains the reactions of the impact mass compensating countermass Device according to claim 3, characterized in that that the countermass has a cylindrical shape and encapsulated Dry ice persists after decompression under space conditions goes from the solid state to the gaseous and thus no new additional fixed Mass in orbit represents Device according to claim 1, characterized in that that the shock mass a deployable from a transport-related storage arrangement out torus-like Structure with big Impact surface and great Moment of inertia because of the outside represents the bending springs mounted compact single masses Device according to claim 1, characterized in that that robotic arms for one in terms of balance of power well-defined shock and countermass from a stowed position into an operating position be deployed to perform the sling motion for the Stoßmassenabwurf Device according to claim 5, characterized in that that at the two discs (leaf springs occupied with additional masses) existing shock mass the forward in the direction of wind disk by spring force pulled back to produce a uniform flat total impact area Device according to claim 6, characterized in that that the robot arms for the shock and the countermass each have balancing weights that complete compensation the centrifugal forces and thus an elimination of the disturbing accelerations on the auxiliary satellites allow to to increase the impact accuracy. Device according to claim 8, characterized in that that the drive unit of the robot arms two synchronously counter-rotating E-motors as well as centrally symmetrical gearboxes contain compensation the bearing reactions. Device according to claim 7, characterized in that that the aggregate for unfolding the star-shaped bending springs of the shock mass two in opposite directions coupled e-motors, whereby the bearing reactions at Unfolding are minimal.