> Are you turning your pusher plate into high energy plasma with the explosion and using that to propel your spacecraft? I think the idea was for the bomb to v

> Are you turning your pusher plate into high energy plasma with the explosion and using that to propel your spacecraft? I think the idea was for the bomb to vaporize a certain amount of propellant. According to wikipedia, the propellant was supposed to be tungsten, but I imagine that any substance would do. For example ice. The vaporized propellant hits the pusher plate and is reflected, resulting in an exhaust jet of very high velocity. The ISP was initially calculated to be between 4000 and 6000 seconds (so 10 times higher than the Space Shuttle), but later when they did the calculations with fusion bombs they concluded that an ISP of 75000 seconds is possible.