>>13830389>fission at best is capable of cutting that up to 2-3 months ( about half )That can actually be done by Starship, based on this porkchop plot done by Casey Handmer on the Mars delta-v requirement and trip time. Somewhat ironically Zubrin makes a point against this, he said that a six-month trip is the best because of an ideal free return and any extra capability should be used to increase the amount of cargo landed
> is there any chance for fusion or fission propulsion in the next 50 years? A low chance of anything that impactful happening, IMO. The Russians have hardware for a NEP tug they're working on. Old space is lobbying for shitty hydrogen solid core NTRs. Kilopower could one day be used for NEP probes, but it would take a large effort to scale it. The creator of it recently did a good talk on that subject if you're interested which I'll link below. Over a 50-year timeframe crewed transport to Mars will probably remain very expensive, this favors cheaper and simpler technology, and with most fusion designs the trip would still be rather long so it would be almost exclusively used by those who decided to move to Mars long term.
It will be hard for the nuclear industry to reach the point where nuclear propulsion is an absolute necessity outside of the higher-level concepts like crewed interstellar missions and intensively colonizing the furthest planets in our solar system. Solar-powered spacecraft are really starting to scale up to higher power levels, they're cheaper with none of the regulatory issues nuclear craft face or will face in an optimistic future. The mass penalty of using solar at greater distances from the sun is starting to get negated, thin films have good specific power. Nuclear reactors still have a large advantage in powering planetary activity on the more distant planets past Mars or slowly rotating planets with longer dark periods. Maybe beamed power technology will change this.
https://www.youtube.com/watch?v=UeuJ1mCa-pc 
