Never gonna make man-cewed spacecraft that will last long enough. We cant make tanks and pipes that will survive oxidation or corrosion and leaks and eventual failures that will survive for decades without replacement. We cant make anything that will last long enough and we dont have room for enough replacement parts and we dont have replicator technology that builds the complicated proprietary vlsi chips that can fail due to radiation bursts or overheating.
The more I see the limited lifespan of things necessary for crewed spacecraft, the less possible it becomes when you look at it realistically through the lifespans of devices we have essentially made nearly perfect now. Even the best made things will not survive as long as needed.
“... devices we have essentially made nearly perfect now”
—
they said the same thing about devices shortly after Graham Bell and about trains in the 50s ...
“... we dont have replicator technology” ... yet
Then again how long some parts last is not as important as the speed at which the craft is traveling. Has Project Orion not been killed in ‘64 travel to Mars and Saturn would be common place today, Mars trip, for instance via Orion, would take 3 days not years. Same for interstellar travel. Alpha Centuri System would have been a 2 year venture with a crew of thousands.