By Dr. S. X. Jin

From: NEN, Vol. 3, No. 10, April 1996, p. 9.

New Energy News (NEN) copyright 1996 by Fusion Information Center, Inc.
COPYING NOT ALLOWED without written permission.

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:

when

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.