If a space vehicle can take off from Earth and get to the moon and even land a capsule there…. and do all that over thirty years ago…. then the technical problems with going to Mars are not that hard. Secondly, if it is shot into space at such a speed as to get to Mars, the energy needed to return is not anything like double that again. The space vehicle would catapault around the planet and fling back to Earth.
Ok. So the main problem isn’t getting to Mars and its not getting back. It’s landing and taking off again. I guess there’s almost no point in going to Mars, taking several months to get there, if our experience is a rapid fire sling shot back home.
A one-way trip to Mars and even landing here would be technically possible, but it would be a one-way suicidal trip. Something a terminally ill person would countenance, or an exchange for a life sentence behind bars maybe. There would be few other takers.
Taking off from the moon was relatively easy because it has very little gravity. Taking off from Mars would require the sort of massive infrastructure that puts Apollo rockets into space from Earth. None of that can be built in our lifetime, if ever… sorry for any dreamers out there.