ELECTRODYNAMIC TETHER PDF

ABOUT ELECTRODYNAMIC TETHER, ITS STABILIZATION, ITS ADVANTAGES. In an “electrodynamic tether drag” system, such as the Terminator Tether, the tether can be used to reduce the orbit of the spacecraft to which it is attached. The motion of the long conducting wire of a tethered satellite across the geomagnetic field creates an emf of about – V/m along the length of the tether.

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These are potentially huge benefits, but electrodynamic tether systems only work when orbiting within a sufficiently strong magnetic field. This number is tetner equal to the square root of the ratio of the ion mass to the electron mass. 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.

You run a current through the wire. However, since the energy conversion means that the orbit of the satellite is lowered, it cannot be used for extensive periods of time without firing rocket thrusters to compensate for the electrodynamic drag force.

Their performance depends on the precise construction of these small structures. So far, so good. An in-plane force is in the direction of travel. A current flows if there is a differential electron number at the ends, so the tether needs to be of sizeable length.

An electrodynamic tether is attached to an object, the tether being fether at an angle to the local vertical between the object and a planet with a magnetic field.

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No, I don’t percent follow that last part either, except to electrodyamic I would guess that the debris has collected it’s own charge over the time it’s been up there. 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 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 Electrons can attain this necessary energy to escape the SCL of the plasma sheath if an accelerated grid, or electron gun, is used.

It will not, however, allow rapid thrustless circling to allow a starship to re-enter a power beam or make numerous solar passes due to an extremely large turning radius of 3.

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The vacuum level represents the potential energy of an electron at rest outside the metal in the absence of an external field. As the beam energy of the electrons is increased, the total escaping electrons can electridynamic seen to increase. The following figure below displays close up visual images of a Spindt emitter. Electrodynamic Tethers Unlike chemical and rocket systems, which must expell a propellant to create thrust, an electrodynamic tether generates thrust through Lorentz-force interactions with a planetary magnetic field.

In other tegher, a full-up deorbit system would need lots of things some method of control, approach, and capture of debris included. The electron and ion density varies according to various factors, such as the location, altitude, season, sunspot cycle, and contamination levels.

This property of EDTs could be used to bring down this junk earlier and in a controlled fashion. Because the tether system does not consume propellant, it can provide very large delta-V’s with a very small total mass, dramatically reducing costs for missions that involve delta-V hungry maneuvers such as formation flying, low-altitude stationkeeping, orbit raising, and end-of-mission deorbit.

The gravity gradient field also known as the “tidal force” will tend to orient the tether in a vertical position. These factors can render the device extremely sensitive to contamination, especially from hydrocarbons and other large, easily polymerized molecules.

Energy Projects – Electrodynamic Tether – NASA

Electrodynamic tether circuits cannot be completed tdther simply using another wire, since another tether will develop a similar voltage. The curves that become horizontal are temperature limited cases.

A power supply is added to the tether system and used to drive current in the direction opposite opposing the electroddynamic EMFthe tether can “push” against the Earth’s magnetic field to raise the spacecraft’s orbit. These issues are explored in greater detail below. The TSS hardware has several major elements: It is plausible that, by using a very large collection area at one end of the tether, enough ions can be collected to permit significant current through the plasma.

The reduction in mass per unit volume, for this same comparison, is 2. There is at present, no closed-form solution to account for the effects of plasma flow relative to the bare tether. In boost mode, on-board power supplies must overcome this motional EMF to drive current in the opposite direction, thus creating a force in the opposite direction, as seen in below figure, and boosting the system.

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If the direction of the current is opposite to the direction it would flow in case of an electrodynamic drag tether, the resulting Lorentz force will also work in the other direction and thus push the spacecraft rather than slow it down. The motion of the conductor across the magnetic field induces a voltage along the length of the tether.

Other current collection mechanisms will then be discussed. It is similar to the winding in an elecrrodynamic motor pushing against the magnets of its armature, causing a torque force. The Tethered Satellite System TSS will deploy and retrieve a satellite from the Space Shuttle orbiter with a tether of up to km in length attached between the satellite and the orbiter.

Such a system can induce several hundreds of volts per kilometer of tether! Further investigation of the double layer phenomenon has been conducted by several people. Views Read Edit View history. The following derivation will describe the exact solution to the system accounting for all vector quantities involved, and then a second solution with the nominal condition where the magnetic field, the orbital velocity, and the tether orientation are all perpendicular to one another.

Eledtrodynamic system comprises a long tether which is electrically conductive with devices rether electron emission and collection. Of course, these measures would have severely restricted the power or propulsion that could be obtained by tether operation and could not be tolerated on an experiment that was not just eelctrodynamic proof-of-concept.

Findings of the board, included in a page document, identified primary causes which accounted for the tether break during deployment of the Tethered Satellite.

Electrodynamic Tethers: Getting into the Swing

Deployment, Experiments and Retrieval. It has been shown that the maximum current collected by a grid sphere compared to the mass and drag reduction can be estimated. The induced current flowing tetherr a conductive tether will interact with Earth’s magnetic field to cause what is called a Lorentz force.

Gravity gradient forces then produce a restoring force that pulls the tether back towards the local vertical; however, this results in a pendulum-like motion Gravity gradient forces also result in pendulus motions without ED forces.

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