[nuke rocketeer]

Nope, A HUGE thick hemisphere of steel with a crew compartment on top and injection ports to squirt a hydrogen bomb under it to detonate a few microseconds later. See this site
http://www.islandone.org/Propulsion/ProjectOrion.html

[HarleyD]

Perhaps I'm foolishly cautious but somehow I don't think that I would like to be the first to test drive an atomic bomb motorized vehicle. Maybe that's why it never became a reality. They couldn't find the volunteers.

[citizen]

THey did that in Lucifer's Hammer.

Good read.

[Ronaldus Magnus]

The rocket equation tells you that an SSTO booster using LH2 fuel and LO2 oxidizer needs a fuel mass fraction of around 0.92. That means that 92% of the take-off weight needs to be ascent propellant, and only 8% is left for everything else.

NASA needs to get outside the box. Chemical propulsion should be an anachronism. From your great link:

"The mass of the vehicle on takeoff would have been on the order of 10,000 TONS (28); most of this mass would have gone into orbit. The bomb units ejected on takeoff would have yielded 0.1 kiloton; initially the ejection rate would have been one per second. As the vehicle accelerated the rate would slow down and the yield would increase until 20-kiloton bombs would have been going off every ten seconds (29). The idea seems to have been for the vehicle to fly straight up until it cleared the atmosphere so as to minimize radioactive contamination."

At a time when the U.S. was struggling to put a single man into orbit aboard a modified military rocket, Taylor and Dyson were developing plans for a manned voyage of exploration through much of the solar system. The original Orion design called for 2000 pulse units, far more than enough to attain Earth escape velocity. 'Our motto was 'Mars by 1965, Saturn by 1970', recalls Dyson."