
It was more than a theoretical concept; it was seriously pursued by
Freeman Dyson et al many years ago. I don't know how well-known this is,
but a high explosive Orion prototype flew (in the atmosphere) in San
Diego back in 1957 or 1958. I was working at General Atomic at the time,
but I didn't learn about the experiment until almost thirty years later,
when 
Ted Taylor visited us and revealed that it had been done. I feel sure
that someone must have film of that experiment, and I'd really like to
see it. Has anyone out there seen it?