FARADAY'S EFFECT IN SPACE
By Dr. S. X. Jin
From: NEN, Vol. 3, No. 10, April 1996, p. 9.
Why was the tether connecting the space shuttle Columbia and the satellite blown apart? One of the possibilities, I think, is the following:
When a conducting bar moves vertically to the bar with velocity V in a homogeneous magnetic field B, according to Faraday's Law or Lorentz Force Law, an electromotive force, emf, will be induced between the two ends of the bar:
e = L V B sin a, sin b,
here, L is the length of the bar, a and b are the angles between magnetic field and the bar and the velocity, respectively.
In the case of the space shuttle Columbia, the B is earth's magnetic field, V the space shuttle's velocity, L the length of the tether (made from copper, nylon and Teflon)* connecting Columbia and the satellite, "a" and "b" is the angle between the tether and the earth's magnetic field. Let's roughly estimate the approximate value of the generated emf:
L = 12.8 mile = 20 Km
B = 0.1 to 0.4 Gauss
V = 17,500 mi/hr = 7.7 Km/sec
and assuming a = b = about 90 degrees
(This is really possible at some position on the orbit of the shuttle),
then the maximum emf could be:
e = 1540 V to 6160 V.
When the space shuttle enters the sunshine region where ionosphere can be formed, the electrically conducting plasma in the ionosphere and the space shuttle-tether-satellite will constitute a closed loop and a large current will flow through the tether. The current will be strong enough to melt and blow apart the tether.
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