ELECTRODYNAMIC TETHER PDF

Part of the NATO ASI Series book series NSSE, volume Abstract Tethers in space can be used for a wide variety of applications such as power generation, propulsion, remote atmospheric sensing, momentum transfer for orbital maneuvers, micro-gravity experimentation, and artificial gravity generation. These are only a few of the host of uses that have been envisioned and proposed for many years. In general, a tether is a long cable even up to km or more that connects two or more spacecraft or scientific packages. Electrodynamic tethers are conducting wires that can be either insulated in part or in whole or bare, and that make use of an ambient magnetic field to induce a voltage drop across their length.

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The 13 day, hour space flight will begin when the Space Shuttle Orbiter Columbia lifts off from Launch Pad 39B and climbs to a statute-mile-high orbit with a Once in orbit, the 5 foot 1.

Mission Commander Andrew M. The Pilot is Scott J. Payload Commander Franklin R. Chang-Diaz Ph. Mission Specialist Jeffrey A. Hoffman Ph. Its objectives on this flight are to demonstrate the ability to deploy and control satellites on long tethers in space and to conduct space plasma experiments that include the generation of electrical power.

The TSS-1 first flew on STS in , but a mechanical problem allowed the satellite to be deployed only to height of feet. The "R" designation indicates a reflight of the same payload with modifications. The satellite carries an additional four instruments. This sphere has an aluminum alloy skin that is electrically conductive, three instrument sensor booms, a payload module for the science instruments and a service module that contains telemetry, power distribution, data handling and navigational equipment.

The middle section contains a gaseous nitrogen tank that will fuel the 12 low powered thrusters that will propel the satellite during deployment above the orbiter. Deployment, Experiments and Retrieval On Flight Day 3, the crew will begin deployment by raising a 40 foot 12 meter deployment boom that elevates the satellite and its support structure to this height. Once released, the satellite will climb upward from the orbiter and away from Earth, aided by gravitational force and the use of its onboard thrusters, to attain a distance of The crew will control the satellite and deployer system from the aft flight deck.

The attached tether, with a diameter of 0. This super- strong and thin strand, also contains a tin coated, insulated copper wire bundle that makes it electrically conductive. Electrons from the ionosphere will be collected at the satellite and will travel down the tether to the orbiter.

The Deployer Core Equipment DCORE instrument in the payload bay will control this flow of electrical current in the tether with two electron generator assemblies. The Shuttle Electrodynamic Tether System SETS will provide measurements of the tether voltage and current and generate an electron beam in support of science investigations.

Other investigations will study the effects of the deployed tether and satellite on the space environment. Approximately 27 hours after deployment, the crew will activate the 5 horsepower electric motor that will rewind the tether and draw the satellite back to the top of the satellite support structure in the payload bay.

The retrieval will be conducted in two phases over a period of 18 hours. This second mission gives scientists an exciting opportunity to explore new areas of plasma physics and electrodynamics. To investigate these effects, the astronauts onboard will work with scientists and engineers on the ground, performing a wide variety of experiments.

These investigations will help us understand things such as the behavior of comet tails and the radio "noise" emitted by Jupiter. Also, by exploring the dynamics of tethered systems, we may develop a variety of possible applications, such as generating electrical power or propulsion for future spacecraft.

Models, accepted by scientists for more than 30 years, are incorrect and must be rewritten. This assessment follows analysis by a joint U. Findings of the board, included in a page document, identified primary causes which accounted for the tether break during deployment of the Tethered Satellite.

The tether failed as a result of arcing and burning of the tether, leading to a tensile failure after a significant portion of the tether had burned away," the report concludes.

The arcing occurred because either external foreign object penetration but not orbital debris or micrometeoroids or a defect in the tether caused a breach in the layer of insulation surrounding the tether conductor. The insulation breach provided a path for the current to jump, or arc, from the copper wire in the tether to a nearby electrical ground Excerpt The tether was designed to carry up to 15, volts DC and handle tensile forces of up to pounds newtons.

It used super-strong strands of Kevlar as a strength-providing member, wound around the copper and insulation.

However, postflight inspection of the tether end which remained aboard Columbia showed it to be charred. The board concluded that after arcing had burned through most of the Kevlar, the few remaining strands were not enough to withstand forces being exerted by satellite deployment Utilizing estimates in the charged density of the earths electromagnetic field and the ionosphere the voltage produces is expected to be several hundred volts per kilometer.

If successful this experiment could produce a lot of electrical power. The advantage to this revolutionary advance in propulsion is that it does not require any rocket fuel If successful electrodynamic tethers could prove a way to greatly decrease the cost of in space propulsion. For example the ISS could keep itself in orbit saving nearly 2 billion dollars in orbit reboost rocket fuel for every 10 years of the stations operation But on Feb.

If anyone knows where a copy might be available please contact us at webmaster This one is from the hand held Infrared Camera and is not as clear as the other one was and it does not have the interview and actual tether deployment portion that the above text was quoted from.

STS Alternate Copy.. In this video they are described as dust and debris by the astronauts and seem no cause for concern.

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US7118074B1 - Electrodynamic tether - Google Patents

The 13 day, hour space flight will begin when the Space Shuttle Orbiter Columbia lifts off from Launch Pad 39B and climbs to a statute-mile-high orbit with a Once in orbit, the 5 foot 1. Mission Commander Andrew M. The Pilot is Scott J.

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Electrodynamic tether

OML theory [13] is defined with the assumption that the electron Debye length is equal to or larger than the size of the object and the plasma is not flowing. The OML regime occurs when the sheath becomes sufficiently thick such that orbital effects become important in particle collection. This theory accounts for and conserves particle energy and angular momentum. As a result, not all particles that are incident onto the surface of the thick sheath are collected. The voltage of the collecting structure with respect to the ambient plasma, as well as the ambient plasma density and temperature, determines the size of the sheath. This accelerating or decelerating voltage combined with the energy and momentum of the incoming particles determines the amount of current collected across the plasma sheath.

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