Orbital deployment of very long tethered structures
Earth-pointing satellites joined by tether, discussing reel back and drag brake orbital deployment techniques and dynamic behavior
Bush, G. B.↗
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Cable arrangement for rigid tethering Patent
Force separation rigid tethering device using cables
Brissenden, R. F.↗
Tether docking of orbiting spacecraft Final report
Computerized simulation of tether docking by orbiting spacecrafts
Greeb, F. J.↗
Inflatable tether Patent
Space expandable tether device for use as passageway between two docked spacecraft
Huber, W. C.↗
Experimental and analytical determination of stability parameters for a balloon tethered in a wind
Experimental and analytical techniques for determining stability parameters for a balloon tethered in a steady wind are described. These techniques are applied to a particular 7.64-meter-long balloon, and the results are presented. The stability parameters of interest appear as coefficients in linearized stability equations and are derived from the various forces and moments acting on the balloon. In several cases the results from the experimental and analytical techniques are compared and suggestions are given as to which techniques are the most practical means of determining values for the stability parameters.
Redd, L. T.↗
Analytical solution for extensible tethers
The mathematical model considers a large particle (m sub 1), such as a space station, and a smaller particle (m sub 2), connected by an ideal, massless tether, i.e., one incapable of sustaining other than tensile loads. The problem situation described offers a practical solution which should be quite useful in certain space flight operations, especially for the transfer of cargo and personnel and for retrieval and rescue operations. The idea is simple in its application and does not appear to require sophisticated hardware. An appealing advantage is that it is infinitely reusable, i.e., it could be rewound and used over and over again.
Eades, J. B., Jr.↗
A practical concept for powered or tethered weight-lifting LTA vehicles
A concept for a multi-hull weightlifting airship is presented. The concept is based upon experience in the design and handling of gas-filled balloons for commercial purposes, it was first tested in April, 1972. In the flight test, two barrage balloons were joined side-by-side, with an intermediate frame, and launched in captive flight. The success of this flight test led to plans for a development program calling for a powered, piloted prototype, a follow-on 40 ton model, and a 400 ton transport model. All of these airships utilize a tetrehedric three-line tethering method for loading and unloading phases of flight, which bypasses many of the difficulties inherent in the handling of a conventional airship near the ground. Both initial and operating costs per ton of lift capability are significantly less for the subject design than for either helicopters or airships of conventional mono-hull design.
Balleyguier, M. A.↗
Technology update: Tethered aerostat structural design and material developments
Requirements exist for an extremely stable, high performance, all-weather tethered aerostat system. This requirement has been satisfied by a 250,000 cubic foot captive buoyant vehicle as demonstrated by over a year of successful field operations. This achievement required significant advancements in several technology areas including composite materials design, aerostatics and aerodynamics, structural design, electro-mechanical design, vehicle fabrication and mooring operations. This paper specifically addresses the materials and structural design aspects of pressurized buoyant vehicles as related to the general class of Lighter Than Air vehicles.
Witherow, R. G.↗
Investigation of electrodynamic stabilization and control of long orbiting tethers
The possibility of using electrodynamic forces to control pendular oscillations during the retrieval of a subsatellite is investigated. The use of the tether for transferring payloads between orbits is studied.
Colombo, G.↗
Tether facility presentation
The history of the tethered satellite system is outlined. Future uses of the system in geophysics, plasmas, and other support activities are presented.
Banks, P. M.↗
UAH/NASA Workshop on The Uses of a Tethered Satellite System
Potential applications of the system are categorized into four areas: geological applications, atmospheric applications, electrodynamics and plasma studies, and technology applications. The multiple-use tethered system with feedback control, will be capable of supporting a payload or satellite suspended from the Shuttle cargo bay, at distances up to 100 kilometers from the Shuttle. Experiments proposed include: geomagnetic mapping, lower atmospheric measurements, ionospheric interactions with large space structures, solar wind transport, and magnetohydrodynamic measurements.
Wu, S. T.↗
Gravity gradient determination with tethered systems
A detailed investigation of the Earth's gravity field is needed for application to modern solid earth and oceanic investigations. The use of gravity gradiometers presents a technique to measure the intermediate wavelength components of the gravity field. One configuration of a gradiometer involves a tethered pair of masses orbiting the Earth and stabilized by vertical gravity gradient of the earth. A mesurement of the tension in such a system, called the DUMBBELL system is described. It allows the determination of the vertical gradient of the anomalous component of the Earth's gravtiy field. Preliminary analysis of the dynamics, mechanization, expected signal levels and noise environment indicates that the Dumbbell system is feasible.
Kalaghan, P. M.↗
Interaction of a tethered satellite with the atmosphere and the resultant environment
The calibration of apparatus like mass spectrometers under free molecular conditions and the design and execution of relevant calibration experiments in the transition regime in low density wind tunnels is addressed. Potential access to the tethered satellite for beam instrumentation is discussed and would involve aerodynamic design input on the satellite, both as to preferred shape for the experiments and aerodynamic control for up-stream pointing. Aerodynamic design for the purpose of stabilization and pointing is also discussed.
Deleeuw, J. H.↗
Interactions of a tethered satellite system with the ionosphere
The Tethered Satellite System will be the first large structure deployed in space. It will react strongly with the magneto-ionic medium of the Earth's ionosphere and will thus be valuable experimental tool. Experiments planned for the structure are discussed. Emphasis is placed on the structures ability to excite a large variety of wave phenomena in the ionosphere using its electromotive force.
Grossi, M. D.↗
Tethered subsatellite as a tool for large body plasma flow interaction studies
It is shown that the qualitative scaling laws can be satisfied for some aspects of certain astrophysical plasma flow interactions by utilizing the Tethered Satellite System (TSS) to deploy and maintain bodies ranging from 50 to 150 m in radius. The stability of the TSS for such large bodies and the limits on body size are considered. The inflation of the bodies is discussed along with the dynamic and electrodynamic forces on the surface of the bodies.
Stone, N. H.↗
Ozone profiles from tethered balloon measurements in an urban plume experiment
NASA Langley Research Center used two tethered balloon systems to measure ozone in the general area of Norfolk, Va. The large balloon system which has an altitude range of 1,500 meters was located at Wallops Island, Va., and the smaller balloon which has an altitude range of 900 meters was located at Chesapeake, Va. Each balloon system measured ozone, temperature, humidity, wind speed, and wind direction from ground to its maximum altitude. From these measurements and from the location of the balloon sites, areas of ozone generation and ozone transport may be inferred. The measurements which were taken during August 1979 are discussed as well as the measurement techniques.
Youngbluth, O., Jr.↗
On vibration control of tethered satellite systems
The general dynamics of a shuttle supported tethered subsatellite system taking into account the longitudinal and three dimensional transverse vibrations is considered. It is noted that control of inherently unstable dynamics during retrieval of the subsatellite can be carried out by letting the rate of change length depend on the state variables in an appropriate manner. Control laws using linear feedback of inplane state variables and nonlinear feedback of out-of-plane state variables are proposed.
Xu, D. M.↗
Electrodynamic Tethers. 1: Power Generator in LEO. 2: Thrust for Propulsion and Power Storage
An electrodynamic tether consists of a long insulated wire in space whose orbital motion cuts across lines of magnetic flux to produce an induce voltage that in typical low orbits averages about 200 v/km. Such a system should be capable of generating substantial electrical power, at the expense of IXB drag acting on its orbital energy. If a reverse current is driven against the induced voltage, the system should act as a motor producing IXB thrust. A reference system was designed, capable of generating 20 KW of power into an electrical load located anywhere along the wire at the expense of 2.6N (20,000 J/sec) drag on the wire. In an ideal system, the conversion between mechanical and electrical energy would reach 100% efficiency. In the actual system part of the 20 KW is lost to internal resistance of the wire, plasma and ionosphere, while the drag force is increased by residual air drag. The 20 KW PMG system as designed is estimated to provide 18.7 KW net power to the load at total drag loss of 20.4 KJ/sec, or an overall efficiency of 92%. Similar systems using heavier wire appear capable of producing power levels in excess of 1 Megawatt at voltages of 2-4 KV, with conversion efficiency between mechanical and electrical power better than 95%. The hollow cathode based system should be readily reversible from generator to motor operation by driving a reverse current using onboard power.
Mccoy, J. E.↗