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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Then raise back up and repeat. Other current collection mechanisms will then be discussed.

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In order to achieve electron emission at low voltages, field emitter array tips are built on a micrometer-level scale sizes.

An EDT can be used to alternately boost to a new location, and then reverse current and use the resulting drag force to decellerate and fine-tune its orbit.

Diminishing returns with collection current and drag area have set a limit that porous tethers might be able to overcome. If a power supply is added to the tether system and used to drive current in the direction opposite to that which it normally wants to flow, the tether can “push” against the Earth’s magnetic field to raise the spacecraft’s orbit. The vacuum level represents the potential energy of an electron at rest outside the metal in the absence of an external field.

This is, however, an extreme oversimplification of the concept. Further discussion of this topic can be found.

Electrodynamic tether – Wikipedia

The major advantage of this technique compared tetjer other space propulsion systems is that it doesn’t require any propellant.

This accelerates space plasma electrons which ionize neutral expellant flow from the contactor. Retrieved 15 March Then there is active collection and emission techniques involved in an EDT system.

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Without the magnetic field present, the current in the wire wouldn’t generate any force. Retrieved from ” https: There has been work conducted to stabilize the librations of the tether system to prevent misalignment of the tether with the gravity gradient. The table below is a summary of some of the potential applications proposed thus far.

Clearing large debris objects with current sats would take a large amount of fuel. As the tether passes through the electromagnetic fields of the Earth’s atmosphere, an electrical charge is expected to build up between the satellite and the orbiter through an electrodynamic process.

Functionally, electrons flow from the space plasma into the conductive tether, are passed through a resistive load in a control unit and are emitted into the space plasma by an electron emitter as free electrons. Capture Operations and Constrains. 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 electrodynami.

System level configurations will be presented for each device, as well as the relative costs, benefits, and validation. For use in EDT system modeling, each of the passive electron collection and emission theory models has electfodynamic verified by reproducing previously published equations and results.

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. As long as the cylindrical tether is less than one Debye length in radius, it electrodynamiv collect according to the OML theory.

Electrodynamic Tethers: Getting into the Swing

This super- strong and thin strand, also contains a tin coated, insulated copper wire bundle that makes it electrically conductive.

A current will flow in the wire, and the satellite will begin to slow down, quickly heading for burn-up in the atmosphere. In this case electrical power supplied by a set of solar arrays is used to run a current through the tether.

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Special EDT phenomena and verification of the EDT system model using experimental mission data will then be discussed. When a tether is moved at a velocity v at right angles to the Earth’s magnetic field Ban electric field is observed in the tether’s frame of reference.

In Gerald H. This voltage depends directly on the magnetic field strength, the velocity, and the length of the wire. Elevtrodynamic Flight Day 3, the crew will begin deployment by raising a elsctrodynamic foot 12 meter deployment boom that elevates the satellite and its support structure to this height.

Spacecraft propulsion Spacecraft components Electrodynamics Magnetic propulsion devices Electrical generators. Assuming that portion becomes more viable in the future, the additional problem of capturing and de-orbiting debris would need to be worked on.

TUI: Engineering the Future

Here’s the deal, if you can summarise the slowing down part in 20 words, I will delete my pathetic effort. In principle, electrodynamic drag tethers can also be used to generate electrical power in space. 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. Conventional solar photovoltaics become ineffective at such distances from the sun, where the solar irradiance is weak.

However, it is more difficult for the opposite negative end of the tether to eject free electrons or to collect positive ions from the plasma.