Discussion on Nuclear Propulsion

When we need to apply one technology to another field. Too much reliance on experts kills the ideas instantly. I would like to support my thesis against the experts. The large distances in space requires more energy dense alternatives to current combustion-based propulsion. Nuclear is the most obvious alternative.

When I proposed to activate tiny nuclear bombs to generate energy pulses, the objection was that due to critical mass it wouldn’t work. A critical mass is a mass of fissile material that self-sustains a fission chain reaction. A steady rate of spontaneous fission causes a proportionally steady level of neutron activity. If the mass of the fissile material is below the critical mass, the reaction will die out; if it's above, the reaction will grow exponentially. As we all know the exponential growth produces a mushroom that ends the rocket and its surroundings. However, anything below that would die out while still producing energy in the meanwhile, E = mc². Even a tiny fraction of the fissile material is fissioned, the energy produced is way more than a complex turbopump combustion engine would produce. More importantly, the system would be less complex and scalable.

The energy by itself wouldn’t produce thrust. We need to accelerate material to achieve that. Gas is the most obvious solution. Liquified gas would be pressurized and expelled by the heat generated by tiny fission reactions.

This simpler rocket design should be implemented on the upper stages of a rocket, that would travel in space. This would generate much longer thrust necessary for planetary missions. More importantly, the planets or moons that have atmosphere can be used to refuel the rocket with much simpler mechanisms. This is a much feasible solution compared to propellent generation from ice. Heat dependent electrolysis process would take ages to fill up a tank. On the other hand, trying to liquify the air which is already very cold is a much simpler and fast solution.