From: Monte Davis 

"Steve Ewing"  wrote:

>This month's Discover mag has an article about the old "nuclear bomb
>drive".  I had heard of it, of course, and thought it certainly feasible,
>but upon reading the article realized for the first time that they had
>intended to take off from Earth!!...

By far the best source is the book "Project Orion" by George
Dyson, Freeman's son. Remember, the idea got started at the height of
atmospheric bomb testing. The fallout from an Orion launch would have been
a small blip against that background.

The numbers worked even on the first-order assumption that the explosions
would be spherically symmetric, with the ship's pusher plate intercepting
well under half the output. But Dyson includes some tantalizing hints about
more efficient "shaped charge" explosions... apparently that
subject is still highly classified 40+ years later!

Monte

--- BBBS/NT v4.01 Flag-5