BY

M.VAMSHI KRISHNA REDDY (11361A0294)

AND

U.BHARDWAJ REDDY(11361A0211)

EEE DEPT,

JAYAPRAKASH NARAYAN COLLEGE OF

ENGINEERING,

MAHABUBNAGAR.

ELECTRO DYNAMIC TETHER

Introduction

Review of existing rocket propulsion mechanism

History of space tethers

Principle

Working

Stabilization of electro dynamic tether

Application

Advantages

Future scope and conclusion

Role of satellite in present communication system

Satellites, spacecrafts and small particles due to explosions among themselves around the earth.

Carrying of extra propellant

Transporting a satellite from the lower orbit to its eventual orbit can take several thousand dollars per kilogram of payload.

EDT as a simple and reliable alternative.

EDT used to deorbit old satellites

Drives energy from rocket fuels

Hydrogen peroxide is one of the commonly used rocket fuels

disadvantage: produces low thrust.

Kerosene is liquid propellant , requires cryogenic systems for there implementation

Propellant as nuclear energy produces radiations.

Giuseppe Colombo – idea of using a long TSS

Connects space walking astronauts to their spacecraft using MMU

The TSS-IR mission and rocket-launched experiments, such as the small expandable deployer system(SEDS) and the plasma motor generator (PMG)

The basic principle of EDT is Lorentz force

I=neAv

For an element dl of the conductor

Idl=nAdlev(N=nAdl,no of electrons in the elements

nAdle=Ne=q(the total charge in the element)

Therefore, Idl=qv

dF=IdlB,i.e, from magnetic Lorentz force,dF=qvB

In simpler form F=QvB

Tidal force will tend to orient tether in vertical position.

In an “electro dynamic 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.

A hallow cathode emitter expels the electrons

It is vital without it , the charge get distributed quickly.

Hollow cathode causes a small tungsten tube to heat up and fill with xenon gas from small tank.

Electrons interact with heat gas to create plasma.

In an “electro dynamic propulsion” system, the tether can be used to boost the orbit of the spacecraft.

It doesn’t require any propellant.

Inherently unstable

The electrodynamic forces also varies and so this pendulum motion develops into liberations in both the in-plane and out-plane direction

The tether configuration feedback algorithm calculates a gain factor based upon the network that the electrodynamic force will perform on tether dynamics

The second algorithm requires only periodic measurements of the acceleration of the tether end mass called end mass acceleration feed back method

These provide thermal stability and efficiency.

Propellant less propulsion for LEO spacecrafts

The microPET propulsion system

The terminator tether satillite deorbit system

Eletrodynamic reboost of the international space station

Power generation in LEO

Space junk cleanup

The operational advantages of electrodynamic tethers of moderate length are becoming evident from studies of collision avoidance.

High efficiency and good adaptability to varying plasma conditions

Boosting tethers of moderate length(~1 Km)

Substantially reduce the weight of the spacecraft

A cost effective method of reboosting spacecraft, such as the international space station

The idea is for the electro dynamic tether to be attached to an unnamed space tugboat that would ferry satellite to higher orbits.

Exploring the outer planets .

The most exotic use of EDT technology would be to propel and power space craft exploring the outer planets.

Tether propulsion require no fuel.

Is completely reusable.

Environmentally clean.

Low cost.

It acts both boosters and breaker for a spacecraft.