Nanofission

I do not under stand why nuclear fission can not be better controlled for space ship propulsion or energy production. What we have now are two inefficient extremes. Either the chain reaction is slowed down to a crawl, creating only a relatively small amount of heat, or the chain reaction goes completely out of control into a all out explosion. What I am wondering is whey the chain reaction can’t be controlled to allow for some useful middle ground.

Space craft powered by nuclear bombs thrown out the back have been envisioned but this is extremely wasteful. You have to set off the explosion far enough behind the push plate that it does no damage and only a small portion of the total force released actually would go toward pushing the craft forward. Suppose instead you could slow down the chain reaction and use all of the matter-turned-into-energy for propulsion.

Nuclear power plants use control rods to keep the chain reaction from going critical. Given critical mass each atom goes on to split multiple other atoms until the whole thing runs away into an explosion. Control rods interfere with the chain reaction so that the atom splittings do not compound each other.

What we need is for a controlled chain reaction to take place. The amount of atom splitting must be allowed to climb initially, and then at some optimum number, the number of atoms being spit must be stabilized by blockage or separation. This would necessitate something very small, very fast, and very precise. Computer controlled nanomachines would probably be required.

Much progress is being made into Nanotechnology and the ability to do this may be just around that corner. Of course you would need a safe test area and if may be that this and other nuclear propulsion testing may have to wait until we have a presence on the moon.