frame your question better
what are the difficulties and roadblocks in deep space travel?
Time,,we are slow as turtles on the indiana speedway or the autobahn of speedy deutchland,,
a source of energy much smaller, more efficient and far more powerful than fossil fuels.
space born radiation,bodies of stars out, waaaaaaayyyyyyyy out yonder,are a hundred times more powerful than our sun,,some flare up to radiate for short periods,a thousand times more radiation than ye olde sonne,,greater spacecraft skin must be R & Dd which will provide protection from same.supplies,enough so the craft residents will be able to sustain lives in somewhat comfortable states,, of negative gravity,no sun to regulate bodily cycles,,how will all these be addressed? stay tuned,they get solved one at a time,