Nuclear Rockets. They still sound futuristic even today. Interestingly enough, they were under active research in the late 50’s and early 60’s as part of the then-planned natural progression of both manned and unmanned space flight.
Nuclear rocketry doesn’t operate the way the common man would normally think; it doesn’t ignite its fuel, but instead simply heats it to much higher temperatures than a conventional rocket would by combustion, which results in (quite simply) more power – It’s a little more in depth than that, but this is explained in the video. In any case, their capabilities far surpass those of any conventional engine.
Of course, that’s all in theory. While nuclear rocket engines have been designed and built, they have never actually been launched and flown. Time just wasn’t kind to the idea, and in today’s climate I highly doubt launching what amounts to a nuclear reactor strapped to a hydrogen tank will ever happen.
The idea though, the technology as built and the science behind such, without going into detail here, are quite fascinating.
As always, enjoy the video!