RU2364557C1 - Spacecraft and method of conducting researches in ultra-high space vacuum beyond molecular protective screen using spacecraft - Google Patents

Abstract

FIELD: space-system engineering.

SUBSTANCE: inventions relate to means and methods of conducting predominatly long-term experiments on low-earth orbit in field of materials production under conditions of ultra-high vacuum. Spacecraft (SC) consists of pressurised section and lock chamber with access door and escape door, mechanical arm, molecular beam epitaxy (MBE) set and molecular protective screen. Lock chamber escape door hatch is made detachable, protective screen is firmly fixed to this hatch on its outside and is equipped with attachment point to the mechanical arm end link. MBE set is connected to the mentioned hatch on its inside. SC is equipped with device for attaching escape door hatch to lock chamber. According to the present invention, method also provides for boosting MBE set together with screen out of the lock chamber, detaching them from SC with mechanical arm, orienting screen to position of protecting MBE set from outside atmosphere flow. Hereafter researches in screen wake sphere are conducted and MBE set is brought back to lock chamber. At this stage MBE set and screen are fixed on the mentioned hatch. When bringing back MBE set to lock chamber using mentioned attachment device, angular and linear errors of mechanical arm overlapping escape door hatch and lock chamber axes are corrected. Mentioned hatch is engaged from mechanical arm and is axially moved till it is completely attached to the chamber with all the necessary docking interface sealing forcing provided. Before starting experiments in screen wake, screen can be oriented in a way to secure maximal illumination of MBE set equipment and screen for its degasification.

EFFECT: increasing data rate and quality of conducted MBE researches and reducing expenses on their realisation.

8 cl, 8 dwg

Description

The invention relates to spacecraft (SC) equipped for conducting experiments in the low Earth orbit in the field of production of materials in ultra-deep vacuum, as well as to methods for conducting these experiments.

Under such conditions, on board spacecraft, in particular, semiconductor heteroepitaxial structures can be obtained by molecular beam epitaxy (MBE). Such spacecraft should be serviced periodically in order to repair and replace equipment, replenish consumables, receive finished products, change crews, etc. These spacecraft can be part of a manned orbital station or be autonomous modules serviced from the station or from the Earth.

Existing spacecraft can achieve and maintain, during the technological cycle of obtaining samples, a vacuum depth of 10 ^-14 -10 ^-17 Torr. Such environmental cleanliness is necessary for growing high-quality single-crystal thin films and multilayer structures consisting of a variety of chemical compounds and solid solutions having the properties of metals, insulators or semiconductors.

These tools include a molecular protective shield (MES), proposed in 1976 by L. Melfi, who together with the authors conducted a theoretical analysis of the state of the gas medium around a disk-shaped screen flying in near-Earth space, and formulated the concept of an orbital laboratory with an ultra-rarefied medium.

The work carried out with the support of NASA showed that if the MZE (polished stainless steel disk) will move around the Earth at an altitude of 200-600 km, then in its wake region a conical trace will be formed, practically devoid of substance (Figs. 1, 2).

From patent sources, a spacecraft is known that contains a cargo compartment with a manipulator, technological and scientific equipment for working in ultra-deep vacuum, placed on the MZE and brought out using the manipulator from the compartment to a region of space remote from the KA, where this equipment is placed in the track area behind the MZE (patent [1] US 4,723,734 A (RJNAUMANN), 02/09/1988).

A similar spacecraft and the method for conducting MBE research with its help were implemented in 1994 by NASA through the MBE space commercial center (project WSF - Wake Shield Facility). The specialized WSF module was designed as a free-flying vehicle (Fig. 2). Maintenance of the device and its preparation for the next launch, with the help of MTKK Space Shuttle, are carried out on Earth.

A disadvantage of the known spacecraft [1] and the like is the use of MTKK for putting into orbit and removal from orbit of a module with WSF equipment, which limits the time of research in an ultra-deep vacuum to several days and sharply increases the cost of these studies.

The closest analogue of the proposed device is a spacecraft containing a sequentially sealed compartment and a lock chamber having an access hatch for access to it from the airtight compartment and an exit hatch for access to outer space, a manipulator mounted outside the spacecraft, an MBE installation with technological and scientific equipment, placed in the transport position in the lock chamber, as well as the MZE (patent [2] RU 2181094 C1 (TsNIIMASH), 04/10/2002).

This spacecraft [2] is a multifunctional serviced vehicle, designed for long-term multi-purpose scientific and applied research in near-Earth space (figure 3).

With the help of this spacecraft, a method for conducting research in an ultra-deep space vacuum behind the MZE is implemented, including the removal into open space from the lock chamber of the MBE installation together with the MZE, their removal from the spacecraft, the orientation of the screen in the position to protect the MBE installation from the external flow of the medium, and the equipment of the MBE installation for conducting research in the field of the wake behind the screen and returning the MBE installation to the lock chamber upon completion of the research data (see the indicated patent [2]).

The disadvantages of the known spacecraft and the method it implements are the difficulty in servicing (in particular, astronauts) the MBE installation, the rather strict requirement for the orientation of the spacecraft during the operation of the MBE in the area of the trace of the MBE, as well as the limited ability to move the screen with the MBE installation in the zone of minimal influence of its own the outer atmosphere of the spacecraft.

The noted drawbacks are mainly due to the design of the system for extending the MBE and MZE installation from the lock chamber into space. The system produces this extension along the longitudinal axis of the spacecraft, which in vacuum studies must coincide with the velocity vector of the spacecraft. In this case, the MES plane can be installed only perpendicular to this axis of the spacecraft. This system also takes up a lot of space inside the lock chamber, making it difficult to work with various equipment, including with the installation of MBE.

The objective of the proposed invention is to overcome the above disadvantages by developing a new constructive solution of the spacecraft and the method of conducting research on MBE using it in the wake of the MZE.

The technical result of the invention is to increase the information content and quality of ongoing research on MBE, as well as reducing the cost of their implementation.

This problem is solved, and the technical result is achieved by the fact that in the proposed spacecraft, in contrast to the known [2], the cover of the exit hatch of the airlock is detachable, the MCE is rigidly attached to the specified cover from its outer side and is equipped with an attachment point to the end link of the manipulator’s hand , the MBE installation is connected to the specified cover on its inner side, while the spacecraft is equipped with a device for docking the exit hatch cover with a lock chamber, including grips, guides, ties and sense installed on the camera body Teli, as well as mounted on the detachable lid mates guides.

The MBE installation can be connected to the cover of the exit hatch of the lock chamber by means of an adapter connected by a detachable connection to this cover.

Heat pipes and panels of the temperature control system can be fixed on the surface of the MZE, providing heat removal from the MBE installation.

At the same surface from the side of the MBE installation, sensors of atmospheric parameters behind the screen can be installed.

The MZE can be made in the form of a disk, to which a thin annular shell is attached at the periphery, equipped with a controlled device for its opening and folding.

The solution of this problem and the achievement of the specified technical result are also ensured by the fact that in the proposed method, in contrast to the known [2], the cover of the exit hatch of the lock chamber is separated by means of the said pushers and, using the specified manipulator, the MZE and the MBE unit attached to this cover are removed from the camera removing them into the hemispherical space of the spacecraft tail, and when the MBE installation is returned to the lock chamber using the indicated docking device, the angular and linear errors are corrected together Ia manipulator axes exit hatch cover and the sluice chamber to intercept said lid arm and in its axial movement until the completion of docking with a camera while ensuring the necessary efforts joint sealing.

In a preferred embodiment, before turning on the equipment of the MBE installation, the screen is oriented to a position that provides maximum illumination of the equipment of the MBE installation and the screen for their degassing. It is also preferable that before switching on the equipment of the MBE installation using the manipulator, the screen was moved to predetermined points in outer space, in which atmospheric parameters were measured behind the screen, and then the optimal point for conducting research in the area of the wake behind the screen was determined and the manipulator moved the screen to this point.

The proposed spacecraft in this example is made in the form of a serviced module of a known multifunctional spacecraft [2] (figure 3).

The proposed spacecraft (Fig. 4) contains a sealed 1 and non-sealed 2 compartments for accommodating scientific and office equipment, a central airlock 3 having an airtight entrance hatch 4 for access to the airlock from an airtight compartment and an airtight exit hatch 5 with a detachable manhole cover 6 ( figure 5).

The spacecraft is equipped with a device 7 (Fig.6b) for docking the cover of the exit hatch 5 with the lock chamber 3, which ensures separation of the cover and subsequent hermetic closure of the exit hatch with a cover.

On the leaking compartment 2 mounted manipulator 8 (figure 4). Inside the airlock is located (in the transport position) the installation of the MBE 9. MZE 10 (figure 5) is attached to the cover 6 of the exit hatch. On the surface of the cover 6 from the side of the lock chamber there are tides for mounting the adapter 11. In the cover 6 there is a sealed electrical connector 12 for supplying power to the outside of the module.

To move the assembly "installation of MBE 9 - cover 6 - MZE 10" on the screen there is a bracket 14, which is attached to the final link 15 of the manipulator 8.

A feature of the proposed design is the complete detachment of the cover 6 from the exit hatch 5 of the lock chamber 3 and the sealing of the lock chamber by this cover from the outside. At the same time, the atmospheric pressure in the airlock presses the cover 6 after it is secured from the frame 16 of the hatch 5. Therefore, to ensure the necessary efforts to seal the joint, the docking device 7 includes grips 17 (Fig. 6b) that attract the cover of the cover 18 to the frame 16 having sealing element.

The links of the manipulator have technological gaps in the places of their connection, therefore the payload moved by the manipulator has a free play of linear and angular position. This determines additional difficulties when placing the technological installation in the lock chamber after completing the experiments, docking and sealing the lid and lock chamber. To overcome these difficulties, the docking device 7 has guides of the “cone-cylinder” type 19, contact sensors 20 and a tightening device 21. On the frame of the cover 6 there are counterparts of the “cone-cylinder” type 22, providing initial contact with the guides 19 and centering the assembly to touch elements 22 of three sensors of the contact 20 of the docking device 7 (figa, 6b).

After preloading the springs of the contact sensors by the manipulator and fixing the touch with three sensors, the frame of the manhole cover is gripped by the grippers 17, the manipulator is put into operation in the mode of free movement of its links, the joint is pulled together by the tightening device 21 (Fig.6b).

For the initial squeezing of the cover 6 when undocking the above assembly and the lock chamber 3, the docking device 7 is equipped with pushers 23, which create a force when undocking the manhole cover and move freely during operations to dock the assembly with the lock chamber.

MZE 10 can be performed in the variants of a hard disk, for example, a polished steel disk (Figs. 5, 6), and a hard disk with a folding shell fixed to the edge of the disk, for example, steel foil, in the form of a circular ring.

The second version of the MZE in the transport and operating positions is shown in FIGS. 4, 7a, 7b. MZE consists of a hard disk 24, on which a folding shell 25 is fixed at the end (Fig. 7a, 7b). Stiffening ribs 27 are attached to the shell, for example, metal elastic spokes that can rotate and be mounted in working position along the radius of the disk. This ensures the folding of the shell in the shape of a circular ring. To rotate the stiffeners, an electromechanical drive 26 is attached to the disk, which provides multiple folding and folding of the shell.

The work of the proposed spacecraft in the implementation of the proposed method is as follows.

The spacecraft is assembled and equipped with scientific and technological equipment in ground conditions and is displayed as part of the space complex (multifunctional spacecraft, Fig. 3) in a working orbit. The manipulator can be mounted on the Earth and displayed together with the spacecraft, or delivered to the manned station from which the spacecraft is serviced, and mounted by astronauts when the module is in the station.

Bringing the installation of MBE in working condition is carried out in the following sequence (Fig.8).

Stage 1. Preparatory operations are being carried out to extend the MBE installation from the lock chamber 3. The access hatch is closed 4. Pressure is released from the lock chamber. A command is given to open the captures 17.

Stage 2. Pushers 23 are the separation of the above assembly (installation, screen and cover) from the lock chamber. The gap between the frames of the lock chamber and the exit hatch cover (working stroke of the pushers) is determined by the power capabilities of the manipulator to further move the assembly.

Stage 3. Next, the manipulator 8 axially extends the assembly until the MBE 9 installation completely exits the lock chamber to a distance at which it is possible to perform shockless rotation of the assembly and reveal the folding part of the protective shield.

Stage 4. The assembly is deployed by the manipulator in a position in which the installation 9 is protected from the incident atmospheric flow by the screen 10 with the implementation of the possibility of its placement in the zone of ultra-high vacuum (Fig.1, 2).

Step 5. The electromechanical actuator 26 is turned on and expands the sheath 25 of the screen. Before turning on the equipment of the MBE installation, the screen 10 can be oriented to a position that provides maximum illumination of the installation equipment 9 and the screen 10 with the Sun and / or Earth for their degassing.

Steps 6-9. The manipulator 8 is expanded to its working length and, according to the laid-out program, performs sequential movement of the assembly in the spacecraft tail hemisphere with a search for the position in which minimum pressure is created behind screen 10 in the MBE technological zone (the highest vacuum).

In this position, the MBE installation equipment is turned on and a predetermined program of experiments in an ultrahigh space vacuum medium is carried out.

After completion of the work program at the MBE installation and cooling of the installation to an acceptable temperature, the installation is transferred to the lock chamber in the reverse order and the lock chamber is filled with the spacecraft atmosphere. In the final section of the pulling together of the frames of the manhole cover and the airlock with the tightening device 21, the pushers 23 move without effort.

For the implementation of the proposed inventions there are all the necessary tools tested in the course of the already conducted space flights.

List of figures

The essence of the invention is illustrated by the following detailed description of an example of its implementation with the accompanying drawings.

Figure 1. Scheme of the conical track behind the molecular screen.

Figure 2. Layout diagram of the WSF module (left) and an idealized diagram of the formation of an ultrahigh vacuum zone behind the screen.

Figure 3. General view of the multifunctional serviced spacecraft (prototype).

Figure 4. The spacecraft according to the invention, made in the form of a serviced module of an orbital vehicle.

Figure 5. The layout of the basic elements of equipment for MBE on the cover of the exit hatch of the lock chamber.

6. Final operations for moving the MBE installation inside the lock chamber and docking the exit hatch cover.

Figa. The manipulator moves the assembly into the lock chamber.

Fig.6b. The contraction of the joint “cover-frame of the airlock hatch”

7. Variant of a molecular protective shield with a hard metal central disk and folding shell.

Figa. The screen is in transport position.

Figb. The screen with the expanded shell during the experiments.

Fig. 8. The sequence of operations in the preparation of equipment MBE on the spacecraft according to the invention.

Claims (8)

1. A spacecraft containing a sequentially sealed compartment and airlock, having an access hatch for access to it from the pressurized compartment and an exit hatch for access to outer space, a manipulator mounted outside the spacecraft, a molecular beam epitaxy (MBE) unit with a technological and scientific equipment, placed in a transport position in the lock chamber, and a molecular protective shield, characterized in that the cover of the exit hatch of the lock chamber is made detachable, molecular protection This screen is rigidly attached to the specified cover from its outer side and is equipped with a mounting unit for the end link of the manipulator’s hand, the MBE unit is connected to the specified cover from its internal side, and the spacecraft is equipped with a device for docking the exit hatch cover with the lock chamber, including on the camera body, grips, guides, couplers and pushers, as well as mating guides mounted on a detachable lid. 2. The spacecraft according to claim 1, characterized in that the MBE installation is connected to the cover of the exit hatch of the lock chamber via an adapter connected by a detachable connection to this cover. 3. The spacecraft according to claim 1 or 2, characterized in that heat pipes and panels of the temperature control system are fixed to the surface of the molecular protective shield, providing heat removal from the MBE installation. 4. The spacecraft according to claim 1 or 2, characterized in that on the surface of the molecular protective shield from the side of the MBE installation, atmospheric parameters sensors are installed behind the screen. 5. The spacecraft according to claim 1 or 2, characterized in that the molecular protective shield is made in the form of a disk to which a thin annular shell is attached at the periphery, equipped with a controlled device for its opening and folding. 6. A method for conducting research in an ultra-deep space vacuum behind a molecular protective shield using a spacecraft according to any one of claims 1-5, including the removal of the indicated MBE together with the molecular protective shield into outer space from the lock chamber, their removal from the spacecraft, orientation the screen to the protection position of the MBE installation from the external flow of the medium, turning on the equipment of the MBE installation for conducting research in the field of the wake behind the screen and returning the MBE installation to the lock chamber upon completion yes research, characterized in that by means of these pushers, the cover of the exit hatch of the airlock chamber is separated and, using the indicated manipulator, the molecular protective shield and the MBE unit attached to the cover are removed from the chamber, removing them into the hemispherical space of the rear part of the spacecraft, and when the MBE unit is returned the angular and linear errors in the combination of the axis of the exit hatch cover and the airlock chamber by the manipulator are corrected to the lock chamber using the specified docking device, They intercept the specified cover at the manipulator and move it axially until the docking with the camera is completed, while ensuring the necessary efforts to seal the joint. 7. The method according to claim 6, characterized in that before turning on the equipment of the MBE installation, the screen is oriented to a position that ensures maximum illumination of the equipment of the MBE installation and the screen for their degassing. 8. The method according to claim 6, characterized in that before turning on the equipment of the MBE installation using the manipulator, the screen is moved to predetermined points in outer space, in which atmospheric parameters are measured behind the screen, and then the optimal point for conducting research in the wake area is determined by calculation behind the screen and move the screen to this point.

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