I think eventually closed cycle nuclear propulsion would be used to exit from earth. A more advanced variation of nuclear thermal rocket with higher specific impulse and still having enough thrust would be more efficient, requiring less propellant than chemical rockets. Since its closed cycle the exhaust won't be radioactive waste.
The issue isn't with nuclear propulsion per say, but what happens if the launch sequence fail (wether its by chemical engine failure or otherwise) with a nuclear reactor (active or not).
I personally disagree, a nuclear salt water rocket is literally a continuous explosion and nothing close has been physically built. I think most feasible rockets would be more advanced variations of nuclear thermal rocket.
Ideally a pulsed nuclear thermal rocket, which can significantly amplify the specific impulse of a nuclear thermal rocket by a factor of 2x to 7x (Isp of 2000 s to 7000 s). I think this engine is the most promising next technological development for nuclear spacecraft propulsion because it is an advancement of the already developed and tested nuclear thermal rocket.
However, in the far far future, then yes, perhaps the engineering challenges with a nuclear salt water rocket can be addressed we would have torch drives like in The Expanse.
rosTopicEchoChamber OP t1_j23w5rg wrote
Reply to comment by Zarkathan in What if we kept pursuing nuclear spacecraft propulsion? by rosTopicEchoChamber
I think eventually closed cycle nuclear propulsion would be used to exit from earth. A more advanced variation of nuclear thermal rocket with higher specific impulse and still having enough thrust would be more efficient, requiring less propellant than chemical rockets. Since its closed cycle the exhaust won't be radioactive waste.
The issue isn't with nuclear propulsion per say, but what happens if the launch sequence fail (wether its by chemical engine failure or otherwise) with a nuclear reactor (active or not).