Well aside from the obvious cost savings when launching on Earth, you need to do the same on Mars to return. in fact Starship's landing and launch profile is conceptually the same on both planets, except that on Earth it needs the booster to reach orbit with any kind of practical payload and the ISRU refueler on Mars.

Making rockets reusable and the cost limited to refurbishment and propellant means you can spend the same amount of funding on greater redundancy. Need to build a landing pad on Mars with robots? How about 4 missions in parallel for the same price you'd be quoted by Boeing for just one? Even if three of them don't work out you're still set to continue.

A manned self sufficient base is probably far fetched, but a small short-term Earth-supplied research station is not something outside the realm of practicality. Remember that we haven't actually landed on the planet AT ALL yet. Baby steps.

But we have had that tech since the 60's.

And you won't be doing four missions in parallel before you've done one that succeeds and as far as I can see with the known technical limitations an economical improvement isn't going to result in a technical success, just in a cheaper failure.

The tech being there isn't helpful if it's too expensive to use at scale. And the computers then were... passable at best. It would be exceedingly hard to adequately control a rocket for an accurate powered landing at the time.

> you won't be doing four missions in parallel

Well you do have the problem of only having an ideal launch window every 2 years, so you do have to do them at the same time with minimal spacing or wait forever to try again. I think the plan was to only do two ships at a time initially though.

Some things you can compensate and plan for, some failures are just natural or random. Like a micrometeorite hitting two of the main computers or something.

Setting up space based resource extraction needed for that could be too expensive or even effectively impossible without reusable rockets.

Which part of a Mars mission requires space based resource extraction?

If you don't want it to be expensive as hell - any part.

Also with space resources you can make the whole thing quite comfortable - big ship, lots of fuel->deltav->short travel time and lots of shielding for when the Sun decides to reach out and touch you.

The part where you need to get back. It's just atmospheric CO2 to complete the sabatier process though.

You could send all the fuel there of course, but that's Apollo levels of throwing money on the bonfire.

Compared to the total cost of the mission I highly doubt that that is going to be the thing it hinges on, besides, all you need to be able to do is get back to orbit from Mars, you don't need to lift the fuel to get back to Earth from the Mars surface, you just leave that parked in orbit.

Anyway, I don't see it happening at all so debating the execution details of things that are in the realm of the solvable already or at best an optimization isn't going to move the needle, the things that need to be solved that we have no clue about are life support, mental health, exposure to radiation for a prolonged period, waste management. Keep in mind that there is no way to re-supply a mission like that en-route and a crew of say four (which would seem to be a minimum for such a mission, and probably is too low from a redundancy perspective) will eat and drink their way through a small mountain over the course of 4 years+ total mission duration.

Believe it or not it's around a 60% reduction in launch mass, so it should cut costs significantly. Tsiolkovsky equation do be like that. https://ntrs.nasa.gov/citations/20140009943

As for all the human related needs, the ISS has been a decades long study on practically all of those. That's kind of why we have it.

Supplying the mission isn't really a fundamental problem since you can send multiple times redundant amounts of all the supplies there on the previous cycle. But yes if something goes wrong they're on their own to solve it for (2 years - time spent there), much like any other mission not in close proximity to Earth. That's why you don't send idiots.

And you're right that there's no point in debating it further, because no amount of arguing will stop humans landing on Mars sooner or later.

> because no amount of arguing will stop humans landing on Mars sooner or later.

One of the points of tfa is that this is unlikely to happen for a variety of other reasons.