There are lots of other technical problems to be solved for interstellar travel, but the four I have mentioned already make it clear why it may well be impossible. The immense distances involved require travel at a very high speed, a significant fraction of the speed of light. But accelerating to that high speed requires prodigious amounts of energy, whatever the propulsion method is. And at that high speed, collision even with tiny dust particles can be catastrophic, so we have to add a heavy shield to the front, which vastly increases the already-enormous amount of energy needed to get it up to speed. And finally, the whole complex mechanism has to work flawlessly for decades or even a century, in an very hostile environment, and without any outside maintenance.
And all this is just for an automated spacecraft. Adding a human cargo adds immense additional problems, because we humans are a pretty fragile species, so protecting us from the harsh radiation of interstellar space, feeding us, providing oxygen, keeping us warm in the immense cold of interstellar space, keeping us sane, etc, etc – for decades if not centuries – adds layers and layers of additional difficult problems.
So yes, we may well manage to put humans on the moon and Mars eventually, and perhaps even keep them there for extended periods of time. But difficult as that will be, it is nothing compared to the difficulties of interstellar travel, despite some of the media hype.
But it is always possible that we have badly misunderstood the physics of the universe, and some new principle will let us travel faster than light, or go through “wormholes”, or “fold space" (as in the SF story Dune), or use some other as-yet unknown technique. But based on what we know now, humans are probably never going to get to the even the nearest star. But perhaps in 10,000 years someone will read this, on a planet orbiting another star, and wonder at how naïve we were in 2022.
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