Space platform assembly for attachment to a space station

Abstract: A space platform assembly (10) designed to be attached to the outer surface of a space station structure (11) for deployment of a tethered space platform (13) into isolation orbit alongside the space station (11). The space platform (13) is designed to carry payloads (19) such as for research experimentation in the microgravity environment of space. The tether comprises a loose power/data umbilical (15) for the deployed space platform (13) while it orbits free of the vibration and g-jitter problems of the space station.

Description: The present invention relates to a space station such as for supporting untended research experimentation in a microgravity space environment. Outer space provides a natural microgravity and high vacuum environment which is not available on earth and which is perfect for certain research experimentation dealing with physical and chemical phenomena which are retarded, blocked, or masked by the effects of gravity. It has been proposed to conduct such experimental research in large, manned space stations but such stations cannot provide the necessary microgravity or vacuum environment within the space station as is present in space external to the space station, due to the physical tolerance limitations of the occupants of the station. Also, manned space stations are large and complex, and they incorporate a plurality of vibration sources and excessive g-jitter which interferes with research experimentation. Free-flying, powered space disks or platforms have been constructed and employed for ultravacuum and low gravity space experimentation. In particular, the Wake Shield and the Eureca platforms are dedicated to providing these environments to payloads. The Wake Shield Facility, is a 3.66m (12- foot) diameter stainless steel disk which is deployed from the cargo bay of a space shuttle and is powered and manoeuvred to a location 48 or 64km (30 or 40 miles) from the shuttle and oriented to shield out the residual atmosphere that remains in low earth orbit, thereby creating an ultra-pure vacuum in its wake. This ultra-vacuum is used as an environment in which to conduct epitaxy in which exceptionally pure and atomically - ordered thin films of semiconductor compounds such as crystalline gallium arsenide can be grown in the ultra-vacuum environment which is free of contaminants. The Eureca Free Flyer is a reusable free flying platform which, like the Wake Shield, is deployed to and retrieved from space via the space shuttle. Eureca is being made available for microgravity payloads which require a very low gravity environment and/or high vacuum. Once deployed from the shuttle bay, it is placed in an orbit in which it remains for up to a year. Free-flying platforms such as Wake Shield and Eureca are expensive, complex and incorporate the disadvantages of vibration and g-jitter since they require power and avionics necessary to accomplish free flight and maneouverability to some distance from the orbiter, and back to the orbiter for retrieval into the cargo bay of the space shuttle for return to Earth. In addition, launch and retrieval by the Space Shuttle is very expensive and severely limits the availability of flights. The present invention is concerned with providing a relatively inexpensive and practical solution to the problems of vibration, g-jitter and space limitations while providing an easily accessible facility for microgravity space experimentation. The article "The Tethered Space Elevator System", Space Tethers for Science in the Space Era - Conf. Proc, vol. 14, 4-8 October 1987, Venice, Italy, pp 365-373, XP002049078 discloses a system in which a space platform is tethered to a support base and is in communication through a power/data cable, according to the preamble of claim 1. According to the invention there is provided a space assembly comprising a space station structure, a support base attached to the space station structure, and a space platform which is releasably-attached to the support base for deployment into space and for recovery from space, and a power/data cable which extends loosely between the support base and the space platform to supply electrical power and data interchange from the space station structure, through the cable, to the space platform, characterised in that the cable comprises means for maintaining the cable loosely tethered between the space platform and the support base and isolated from the vibration of the space station structure, whereby the space platform can be released into orbit alongside the space station, is loosely tethered to the support base and isolated from any vibration thereof. The present invention enables the provision of a novel assembly of a support base designed to be secured to an external surface of a space station structure, and a payload-supporting platform which is releasably attached to the support base and is loosely tethered to the support base by means of a power/data cable or umbilical which enables the platform to be released from rigid attachment to the space station and to orbit alongside the space station to provide a large platform for conducting and controlling desired research experiments in the microgravity atmosphere of space, isolated from the vibration, g-jitter and space limitations encountered when such experiments are conducted within the confines of the space station. In order that the invention and its various other preferred features may be understood more easily, some embodiments thereof will now be described, by way of example only, with reference to the drawings, in which:- Figure 1 is a schematic illustration of a support base/payload- supporting platform assembly attached to a space station structure, showing the platform latched or otherwise secured to the support base, and, Figure 2 corresponds to Figure 1 but shows the payload-supporting platform deployed from the support base for independent orbit, alongside the space station structure, while being loosely tethered to the support base by a power/data cable. Referring to the drawings, the present assembly 10 is illustrated in coupled position in Figure 1, secured to an outer surface of a space station structure 11. The assembly 10 comprises a support base 12, a payload-supporting platform 13, latching means 14 releasably-attaching the platform 13 to the base 12, and a power/data cable 15 and dispenser 16 which contain power and command data lines communicating between the space station 11 and the platform 13 to provide for remote unlatching deployment and attitude control of the platform, retrieval docking, and re-latching of the platform, power for initiating and controlling experimentation, command data supply and information receipt. The assembly support base 12 is secured to the outer surface of the space station structure 11 by an attachment means 17, such as bolt means. The cable dispenser 16 preferably comprises a remotely-controlled spool means for expending and retracting the cable 15 to deploy and recapture the platform 13, in cooperation with remote activation of the latch means 14 between open position, for release of the platform 13, and closed position, for recapture. The cable 15 may contain a strain relief loop 18 (Figure 2) or vibration control transducers (smart cable) to increase the isolation of the deployed platform against any vibration or g-jitters of the space station structure 11. Figure 2 illustrates the platform 13 released from and deployed in orbit spaced from the support base 12 and the space system structure 11. The platform 13 has fixed thereto a plurality of payloads 19 such as control means, reactors, chemical supply stations, heaters, pumps and/or other integrated elements necessary to conduct the desired experimentation in the microgravity environment of space. The platform 13 preferably has its own attitude control system consisting of electric thrusters which are remotely-controlled from within the space station, via cable 15, to deploy the platform 13 and control its attitude at the desired isolation distance from the space station structure 11, using a very low continuous thrust which can counteract the air drag, tidal-and solar wind-induced acceleration to maintain stationary attitude and orbit relative to the space station. The electric thrusters on the platform 13 are also used for manoeuvring and retrieval of the-platform 13, in cooperation with the tether cable 15. Payloads 19 can be refreshed or exchanged while the platform 13 is reattached to the base 12 or is secured to the space station by robotic arms, and then the platform can be re-deployed for another period of isolated orbit. It will be apparent to those skilled in the art that the present orbiting platform 12 can be utilized for a wide variety of purposes in addition to microgravity experimentation, such as astronaut support systems and supplies, audio and visual space exploration equipment and scientific experimentation which require or benefit from the properties of a space environment in addition to microgravity, such as ultra-vacuum conditions. While preferred embodiments of the invention have been disclosed in detail, it should be understood by those skilled in the art that various other modifications may be made to the illustrated embodiments without departing from the scope of the invention as described in the specifications and defined in the appended claims.

Claims: A space assembly (10) comprising a space station structure (11), a support base (12) attached to the space station structure (11), and a space platform (13) which is releasably-attached to the support base (12) for deployment into space and for recovery from space, and a power/data cable (15) which extends loosely between the support base (12) and the space platform (13) to supply electrical power and data interchange from the space station structure (11), through the cable (15), to the space platform (13), characterised in that the cable comprises means (18) for maintaining the cable (15) loosely tethered between the space platform (13) and the support base (12) and isolated from the vibration of the space station structure (11), whereby the space platform (13) can be released into orbit alongside the space station structure (11), is loosely tethered to the support base (12) and isolated from any vibration thereof. A space assembly as claimed in claim 1, in which the assembly comprises a power means (16) for supplying and retracting the power/data cable (15) by remote control means. A space assembly as claimed in claim 2, in which the power means (16) is attached to the support base (12). A space assembly as claimed in any preceding claim, in which said means (18) for maintaining the cable loosely tethered comprises a strain relief loop in the power/data cable. A space assembly as claimed in any one of the preceding claims, in which the space platform (13) supports a plurality of payloads (19) which are integrated, powered, and controlled to conduct research experimentation in the microgravity environment of space while isolated against the vibration and g-jitter conditions present within a manned space station (11). A space assembly as claimed in any one of the preceding claims, in which the space platform (13) includes electrical power means for the deployment, manoeuvring and return of the space platform to the support base (12).

Inventors: WATKINS JOHN L, WATKINS, JOHN L.
Applicants: LORAL SPACE SYSTEMS INC, SPACE SYSTEMS/LORAL, INC.
Application year: 1997
Main classification: B64G1
IPC codes: B64G1