"Steve Willner" wrote in message
...
In article ,
Jonathan Silverlight
writes:
A Busssard ramjet, as you may already know. Doesn't work, for all sorts
of reasons.

Hard to build, no doubt, but "doesn't work?" Why not? Are you
thinking of the mythical "ramjet speed limit?"

Isn't it to do with the problems of getting hydrogen
to fuse. Most practical attempts use heavier isotopes.
I found this in a quick scan on Google but there is
bound to be something more detailed around (skip the
text quoted and above it):

http://www.asa3.org/archive/asa/200007/0217.html

George