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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Tethered Remote Manipulator

Remote-manipulator concept for retrieval or inspection of objects in outer space applied to underwater or in tanks of hazardous chemicals. System includes tether head on outer end of tether cable wound on motor-driven takeup reel. Head includes mounting plate with four canted thrustors facing rearward, solid-state camera with patterned sources of light facing forward, and pneumatic inflatable end effector. Also includes device to cut head loose in emergency. Intended for use in places beyond reach of jointed rigid-arm manipulator and where unsafe or impractical to send humans.

Bryan, Thomas C.↗
NASA NTRS1989

Measuring Tension In A Tether

Proposed instrument measures tension in tether and transmits data on tension so tension monitored or adjusted as necessary. Positioned along length of tether, which measures tension only at ends. Device includes strain gauge to sense tension. Output of strain gauge controls modulation of battery- or solar-powered radio transmitter. In another version, transmitter receives radio signal on one frequency and returns signal on another frequency with modulation signifying tension. Yet another version, data on tension carried on beam of light. Laser-diode transmitter powered by battery, radio beam, beam of light, or solar energy.

Hinman, E. M.↗
NASA NTRS1988

Electrodynamic tether system study: Extended study

This document is the final report of a study performed by Ball Space Systems Division (BSSD) for the NASA Johnson Space Center under an extension to contract NAS9-17666. The tasks for the extended study were as follows: (1) Define an interface between the Electrodynamic Tether System (ETS) and the Space Station (SS); (2) Identify growth paths for the 100 kW ETS defined in the original study to a 200 kW level of performance; (3) Quantify orbit perturbations caused by cyclic day/night operations of a Plasma Motor/Generator (PMG) on the SS and explore methods of minimizing these effects; (4) Define the analyses, precursor technology, ground tests, and precursor demonstrations leading up to a demonstration mission for an electrodynamic tether system that would be capable of producing maneuvering thrust levels of 25 newtons; and (5) Propose a development schedule for the demonstration mission and preliminary cost estimates.

Source record↗
NASA NTRS1988

Mars orbital tethered sample return: The feasibility and uses of obtaining entrained particulates from the atmosphere

By employing technology developed for the Tethered Satellite Program, it appears feasible to obtain Martian dust samples from the atmosphere using an orbiting spacecraft. If collected during an annual dust storm, such a sample would contain a global selection of windborne materials. Atmospheric dust sampling is of importance to the study of Martian surface geochemistry, soil mechanics, atmospheric dynamics, and atmospheric and radiative transfer. Tethered sample return offers two key advantages over a lander sample return: relative simplicity and low spacecraft weight. In another vein, the collection of atmospheric dust by a lander sample return mission is itself of scientific merit. By employing a mast and collection plate aboard a lander mission, it is possible to obtain dust from distant locations transported as entrained material in the local aeolian environment.

Stern, S. A.↗
NASA NTRS1988

A low earth orbit skyhook tether transportation system

This paper discusses the design concept of a structure, called the Skyhook Tether Transportation System (STTS) which may be used to transport mass to higher or lower orbits or to capture objects from higher or lower orbits. An analysis is presented for the possibility of the STTS to perform the function of transporting masses suborbitally, capturing the objects, and then releasing them to a higher orbit, the GEO, the moon, or for an escape. It is shown that, although the possibility of such a system is limited by the tether strength, even a modest system can yield considerable benefits in propellant savings if it is used in combination with chemical propulsion.

Penzo, Paul A.↗
NASA NTRS1988

Tethered versus attached cryogenic propellant storage at Space Station

The space-based orbital transfer vehicle will require a large cryogenic fuel storage facility at the Space Station. An alternative to fuel storage on-board the Space Station is on a tethered orbital refueling facility (TORF) which is separated from the Space Station by a sufficient distance to induce a gravity gradient to settle the propellants. Overall costs and benefits of a particular tethered facility design have been defined relative to a representative zero-gravity facility on the Space Station. Results indicate that the TORF hardware and operations costs are roughly 40 percent higher than the comparable zero-g facility costs. The cost difference is negligible when compared to the launch cost of the fuel over the facility 10-year lifetime.

Fester, Dale A.↗
NASA NTRS1989

The tethered satellite system - An electrodynamic mission

The tethered satellite system, a joint U.S.-Italian project to develop a Space Shuttle-based facility for deploying satellites either radially toward or away from the earth to distances up to 100 km, is described with particular attention given to its first mission (TSS-1). The main objective of the TSS-1 mission is to verify the capability of the facility to deploy, control, and retrieve a tethered satellite. The TSS-1 mission will provide a 20-km scale size space plasma physics research facility that moves at supersonic sub-Alfvenic speeds through the natural and unbounded ionospheric magnetoplasma.

Stone, Nobie H.↗
NASA NTRS1989

Calculating the electromagnetic field on the earth due to an electrodynamic tethered system in the ionosphere

A method is presented for calculating the electromagnetic wave field on the earth's surface associated with the operation of an electrodynamic tethered satellite system of constant or slowly varying current in the upper ionosphere. The wave field at the ionospheric boundary and on the earth's surface is obtained by numerical integration. The results suggest that the ionospheric waves do not propagate into the atmosphere and that the image of the Alfven wings from a steady-current tether should be greatly broadened on the earth's surface.

Estes, Robert D.↗
NASA NTRS1989

How tethered systems can benefit microgravity research in the Space Station era

The use of a tethered movable orbiting laboratory for microgravity research is examined. The relation between reduced microgravity carriers and acceleration levels, and the effects of acceleration levels on in-orbit experiments are studied. The tuning of the gravity level at a space laboratory by employing a tether is described. The applications of the variable gravity environment to research in fluids and materials sciences, life sciences, separative techniques, and physical and applied chemistry are discussed.

Lavitola, Maria Stella↗
NASA NTRS1988

Status of tethered satellite system (TSS) development

The Tethered Satellite System (TSS) is a cooperative space system and science development activity being carried out by the U.S. and Italy. The TSS will involve an instrument-laden satellite that can be deployed from the cargo bay of the Shuttle Orbiter using a long tether to altitudes both above and below that of the Orbiter. This paper discusses the predevelopment activities, development approach and management relationships, current hardware and software designs and interfaces, overall science experiment status and plans, and mission operation planning for the first TSS mission.

Laue, Jay H.↗
NASA NTRS1988

The use of tethers for an artificial gravity facility

The principles of operation and the design of the Artificial Gravity Research Facility (AGRF), which is a centrifuge to be constructed and operated for research and development purposes in a low-earth orbit, are examined, with particular attention given to the use of tethers for this facility. The differences and similarities between the AGRF and the previous artificial-gravity concepts are discussed in the framework of modern understanding of the effects of partial gravity and rotating environments on the human organism. The impact of tension-stiffened tethers on the system mass of the AGRF is examined, together with their effect on space operations and safety.

Lemke, L. G.↗
NASA NTRS1988

A tethered astrometric telescope facility

A comparison is made between a tethered platform and a kinematically attached payload. Tethered platforms are capable of achieving a high level of passive vibration attenuation while reducing exposure to induced contamination to near-background levels. The Astrometric Telescope Facility, a payload being considered for operation from the Space Station, is described in detail.

Lemke, L. G.↗
NASA NTRS1989

A vectorized algorithm for 3D dynamics of a tethered satellite

Equations of motion characterizing the three dimensional motion of a tethered satellite during the retrieval phase are studied. The mathematical model involves an arbitrary number of point masses connected by weightless cords. Motion occurs in a gravity gradient field. The formulation presented accounts for general functions describing support point motion, rate of tether retrieval, and arbitrary forces applied to the point masses. The matrix oriented program language MATLAB is used to produce an efficient vectorized formulation for computing natural frequencies and mode shapes for small oscillations about the static equilibrium configuration; and for integrating the nonlinear differential equations governing large amplitude motions. An example of time response pertaining to the skip rope effect is investigated.

Wilson, Howard B.↗
NASA NTRS1990

The radiation budget of stratocumulus clouds measured by tethered balloon instrumentation: Variability of flux measurements

Measurements of longwave and shortwave radiation were made using an instrument package on the NASA tethered balloon during the FIRE Marine Stratocumulus experiment. Radiation data from two pairs of pyranometers were used to obtain vertical profiles of the near-infrared and total solar fluxes through the boundary layer, while a pair of pyrgeometers supplied measurements of the longwave fluxes in the cloud layer. The radiation observations were analyzed to determine heating rates and to measure the radiative energy budget inside the stratocumulus clouds during several tethered balloon flights. The radiation fields in the cloud layer were also simulated by a two-stream radiative transfer model, which used cloud optical properties derived from microphysical measurements and Mie scattering theory.

Duda, David P.↗
NASA NTRS1989

Atmospheric deployment of tethered systems - The proposed TSS-2 flight demonstration

Areas of strong user interest in the atmospheric deployment of tethered systems are addressed. They include hypersonic and aerothermodynamics research to support next-generation aerospace vehicle design, lower thermosphere scientific research supporting global change monitoring and earth systems investigations, and payload recovery/trash disposal from Space Station Freedom. The proposed tethered flight demonstration TSS-2 is described.

Couch, L. M.↗
NASA NTRS1990

Proposed aerothermodynamic experiments in transition flow using the NASA/ASI tethered satellite system-2

Aerothermodynamic, aerodynamic, and atmospheric science data acquired between 55 and 150 km has been limited by the lack of vehicles or platforms capable of sustained operation at these altitudes. Tethered satellites, which have been under study for this purpose by NASA, the Italian Space Agency (ASI), and others for more than a decade, are expected to become a reality by mid-1991. This approach, in which an instrumented platform is maintained at a desired altitude by a tether attached to a host vehicle orbiting at higher altitudes, will provide the first opportunity to obtain steady state data over an extended period encompassing one or more orbital revolutions. This paper describes the objectives and measurement methods for the first of the facility-class satellites, the TSS-2, which is proposed for a 1995 deployment, and gives the status of the experiment definition. Monte Carlo modeling of the flow fields at 130 km around the baseline 1.6 m diameter sphere is discussed and illustrative results of the modeling given.

Wood, George M.↗
NASA NTRS1990

Currents between tethered electrodes in a magnetized laboratory plasma

This paper describes the experimental setup and measurement techniques used to investigate currents between tethered electodes in a magnetized laboratory plasma. Experimental results include information on current propagation, the formation of wave wings, the limits of current collection, nonlinear effects and instabilities, charging phenomena, and the characteristics of transmission lines in plasma. The results were found to support certain predictions on tethers in space (e.g., the MHD far zone or the motional emf) while contradicting others (e.g., distant current closure), and revealed such new phenomena as current disruptions, current-neutralized beams, and wing spread.

Stenzel, R. L.↗
NASA NTRS1990

Saturn ring rendezvous mission utilizing a tethered sub-satellite

By combining the advanced technologies of constant-thrust propulsion and space tethers in a planetary mission, it may be feasible to perform a complete radial and azimuthal survey of the Saturnian ring system from close range (about 10 km) in a period of some 300 days. Constant-thrust propulsion would provide the means of 'hovering' above the rings while simultaneously spiraling radially inward toward Saturn. Use of a tethered sub-satellite at a distance of 500-1000 km from the main spacecraft would permit an instrumented package to achieve a significant azimuthal angular rate relative to the rings. Exhaustive 360 deg azimuthal mapping at one or two selected distances from Saturn could be performed in a few tens of days.

Bright, Larry E.↗