1950s Project Orion (NOT the NASA Orion Capsul) is also A Nuclear Engine spaceship
that use Atomic bombs as fuel !
in early stage of project they wandet groundlaunch from Nevada or Pazific
later desgin used Booster like Saturn V first stage to bring Orion up to 40 Km high
then orion start its nuclear Kraaaboom drive
USAF wandet ORION as orbital Platform for Counterstrike in case of Nuclear War
http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)
I think virtually everybody on this forum knows what the 50s Project Orion idea was.
Some of us think, that the 50s version was good, and its the 2000s version that is bad.
The 50s version remains the only feasible method with current technology to launch multi-thousand (or even million) ton payloads into space, and the only feasible way for manned exploration of the outer solar system. Perhaps the Japanese will make the space elevator work (but the materials problems are hard), but the space elevator won't take you to Saturn.
The radiation risk is actually quite small. A statistical increase (i.e. not specifically identifiable cases) by a literal handful of cancer cases per Orion launch from Earth. And that's using 50s level technology, relatively dirty bombs, and few precautions. Today, the risk would be much lower with better bombs, better material science (less fallout), and simple precautions, like launching on top of a 2nd pusher plate, instead of from the ground level.
Personally I would consider the risk acceptable even for a few hundred Orion launches per year using 50s technology. The reason is simple, we can then move a lot of dirty processes off Earth once we establish a substantial space presence (and we could do that with far less than few hundred Orions per year - just a handful of Orions might be enough) - for example - solar power from space, heavy metal mining on the moon. The number of people we currently already kill from burning fossil fuels (which also contribute to cancers as well as contributing to other problems like global warming), and putting metals into the environment, etc., dwarf any number of early cancer deaths that would be caused by Orions -- so if Orion was implemented as part of a planned program to replace these dirty process, it would offer a net saving of lives, and allow us to improve the environment.
As for space exploration, Arthur C. Clarke, Werner von Braun, Niels Bohr, as well people connected to the project (like Freeman Dyson and General Thomas S. Power) all thought Orion a good idea.