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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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This figure is symmetrically set up so either end can be used as the anode. This idea could act as a Hypersonic Airplane Space Tether Orbital Launch system, or be utilized to handle other launch systems other than hypersonic electrldynamic. In addition to the electron thermal collection, other processes that could influence the current collection in an EDT system are photoemission, secondary electron emission, and secondary ion emission.

This story is a poignant tale of what might have been in the last century of American space travel. This theory accounts for and conserves particle energy and angular momentum.

Electrodynamic Tethers: Getting into the Swing

Geophysics Atmospheric sciences Atmospheric physics Atmospheric dynamics Atmospheric dynamo Atmospheric chemistry Earth’s magnetic field. Hollow cathodes emit a dense cloud of plasma by first ionizing a gas.

All of the electron emission and collection techniques can be summarized in the table following. The story takes maybe fifteen minutes to read – it’s well worth it! Many of the ionized xenon atoms are accelerated into the walls where their energy maintains the thermionic emission temperature.

However, an uninsulated tether will be able to collect free electrons over a large part of its length instead of just at its tip. 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.

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. While it is not a colorful as the Rasta space tug from William Gibson ‘s Neuromancerit could provide a technology that takes low-flying satellites to a new level. In a loose sense, the process can be likened to a conventional windmill- the drag force of a resistive medium air or, in this case, the magnetosphere is used to convert the kinetic energy of relative motion wind, or the satellite’s momentum into electricity.

Much has to be learned about the interactions between the sheath structure, the geometry of the mesh, the size of the endbody, and its relation to current collection. The main benefit with respect to an aerobraking tether, which can also be used to slow down a.


Any exposed conducting section of the EDT system can passively ‘passive’ and ‘active’ emission refers to the use of pre-stored energy in order to achieve the desired effect collect electron or ion current, depending on the electric potential of the spacecraft body with respect to the ambient plasma. I am flummoxed as to how they slow down the damn thing. When the conducting body is negatively biased with respect to the plasma and traveling above the ion thermal velocity, there are additional collection mechanisms at work.

Stanford Research Institute data sheet.

The characteristics of the TSS which are related to high voltages, electrical currents, energy storage, power, eleftrodynamic the generation of plasma waves are described. 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.

The choice of the metal conductor to be used in an electrodynamic tether is ekectrodynamic by a variety of factors. Post a comment Name This “electrodynamic drag force” will decrease the orbit of the tether and its host spacecraft. The electron and ion density varies according to various factors, such tetther the location, altitude, season, sunspot cycle, and contamination levels. Such a system can induce electrldynamic hundreds of volts per kilometer of tether! 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.

Electrodynamic tethers EDTs are long conducting wiressuch as one deployed from a tether satellitewhich can operate on electromagnetic principles as generatorsby converting their kinetic energy to electrical energyor as motorsconverting electrical energy to kinetic energy.

It is believed that the failure was caused by an electric arc generated tetber the conductive tether’s movement through the Earth’s magnetic field.

In field emission, electrons tunnel through a potential barrier, rather than escaping over it as in thermionic emission or photoemission.

Electrodynamic tether

Once this is accomplished it will be possible to apply this theory toward determining optimizations of system attributes. Bill Christensen, Bill Christensen catalogues the inventions, technology and ideas of science fiction writers at his website, Technovelgy.

In this fashion, the voltage that is electromagnetically induced within the tether can cause current to flow through the surrounding space environmentcompleting an electrical circuit through what appears to be, at first glance, an open circuit. In this regard, see also homopolar generator. This accelerates space plasma electrons which ionize neutral expellant flow from the contactor.

To calculate the in-plane and out-of-plane directions, the components of the velocity and magnetic field vectors must be obtained and the force values calculated. Also, development has been slow; a program planned for launch inProSEDs, was repeatedly postponed and ultimately canceled.


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.

These investigations will help us understand things such as the behavior of comet tails and the radio “noise” emitted by Jupiter.

If the tether geometry is a flat tape, then an approximation can be used to convert the normalized tape width to an equivalent cylinder radius. By using this site, you agree to the Terms of Use and Privacy Policy. 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 result is that the tether system loses kinetic energy, and thus slows down. To make this useful, we need to have an electric current, which means we need electrons going in at one end of the tether and getting out at the other end, being driven through the wire by the voltage.

That is, it will slow down and seek a lower orbit, eventually crashing on the planet. Current in a wire cutting through a magnetic field induces a force. However, before the break, TSS-1R demonstrated that a satellite at a high positive potential could collect an anomalously large electron current.

In addition, the collection along a thin bare tether is described using orbital motion limited OML theory as well as theoretical derivations from this model depending on the physical size with respect to the plasma Debye length. Elmo’s fire Ball lightning. However, tethre inspection of the tether end which remained aboard Columbia showed it to be charred. EFN is the electric field that exists between the electron emissive tip e,ectrodynamic the positively biased structure drawing the electrons out.

Electrodynamic Tethers: Getting into the Swing

You may remember from high school physics that when you move a conducting wire through a magnetic field, a voltage is induced along the wire.

Understanding how the predicted performance deviates electrodynamuc theory is important for these conditions. The vacuum level represents the potential energy of an electron at rest outside the metal in the absence of an external field. Primary objectives of KITE are to obtain data on the fundamental characteristics of the original EDT components In other words, a full-up deorbit system would need lots of things some method of control, approach, and capture of debris included.