I told him that it seemed quite absurd and unattainable, at present or near-future levels of technology. I told him, we could probably send a crew, as long as we didn't expect to get them back!

Going to LEO with the ISS has been an amazing achievement, and we (mankind) have proven that it's a sustainable thing: to maintain a crewed station in orbit, and send regular resupply missions up there. It's been a landmark of cooperation, even while USA-Russian relations are frosty.

Now, getting to the Moon and landing on it is also an achievement. Putting a crewed station in permanent orbit around the Moon, or a permanent crewed Moonbase, would be an important milestone, but we must understand that those goals are orders-of-magnitude harder than what the ISS has done.

Humans going to Mars, on the other hand, is absurd, and would be so performative in the first place. You could, hypothetically, send all your cargo up to Mars first, in advance of the crew, and then the crew could utilize the cargo upon arrival. Perhaps.

But we simply couldn't count on the survival of a return-crew mission to Mars. It's a full 6 months in transit, one-way! Anyone who has ever seen an ISS Expedition get dragged out of their capsule, loaded onto gurneys, and wheeled into the hospital, you will know that a 6-month weightless journey will incapacitate each and every person who goes. I once heard an ISS astronaut describe the things they're "not allowed to do" by NASA after arriving home. They need to re-learn many gravity-bound skills. They aren't even allowed to go jogging! They would hit Mars and be utterly useless as human beings, much less scientists or explorers.

The reality of the mythical Mars mission is that it's a pipe-dream which is sold to us by the military-industrial complex in order to fund their current missions and current science, which achieves achievable things, mostly with robots. And I'm fine with sending robots to Mars and Europa and Uranus. Sending humans is counterproductive.