A new way of DEcelerating

[T.L.G.vanderLinden@student.utwente.nl (Timothy van der Linden)]

I'm currently reading a book "Extraterrestials, where are they". It's not a
sf and it dicusses the the possibilities of alien life and its exploration
of the universe. It also has a chapter about propulsion systems. They came
up with several methods for acceleration (about the same as we did) and only
one feasable deceleration method, that of pellets being sent 100 years
before the real launch.
There was another method not found by us, that method had a rather bad
theoretical background so they couldn't say if it would work as well as we
would like. I have a hard time understanding it, but it has to do with using
electromagnetic (EM) coupling of the interstellar PLASMA. It seems that
there are also some ions in the ISM. The EM influence of these ions may be
somewhat smaller than the normal pressure of the uncharged ISM. It would
require a HUGE array of conducting lines, which could be towed (passively)
behind the ship. I think, but am not sure that the EM turbulence induced by
the lines and the plasma will reduce the speed of the ship.
(This system is called the "Alven Propulsion Engine" and was discovered by
Drell, Foley and Rutherman in 1965)
They calculated that the mass/surface ratio should be less than 1E-9 kg/m^2
if you want to stop in a feasable time, this is of course not very easy to
make. They suggest to use 1-micron-diametre wires.

So in all, it is a possibility but there have to be done experiments to make
sure it will work well enough. Since our ship is assumed to be much heavier
than the one the book was suggesting, we need a HUGE (I don't know how huge)
array of conducting lines. This method has an attractive side, that of
passive braking.


Timothy