From Kristjan Valur Jonsson
In your article about the space elevator
(5 May, p 24),
why is it that there is no mention of the Coriolis force?
The space elevator will have to transfer angular momentum to the cargo going
up there. Unless this is precisely matched by cargo going down it will result in
a net change of angular momentum of the elevator, which will then begin to drift
out of phase with the Earth. This would ultimately result in a catastrophic
failure as it wraps itself around the equator like a tethered ball around a
pole.
Even if one manages to balance the books for angular momentum in the long run
(with equal downward mass transfer) every carriage is likely to cause lateral
oscillations in the whole structure, which would be hard to manage. It seems
that one would still need to use large amounts of rocket fuel going in both
directions to counter the Coriolis force.
Karl Ziemelis replies: The angular momentum is transferred by the Earth
itself, which slows down as a consequence (but not by very much). Similar
criticisms were levelled against the original proposal, but were long ago shown
to be non-problems.
Advertisement
Berlin
