"Jim Greenfield" wrote in message
om...
"George Dishman" wrote in message
...
"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

Cart the fuel source along if absolutely necessary,

Sure, but it wouldn't be a ramjet then.

but early Murray
River steamboats were so successful because they could collect their
fuel straight off the bank

The hydrogen in space is almost entirely the plain vanilla
flavour that takes more energy to contain than you get out.
Disappointing, but that's the problem in a nutshell.

George