Whenever someone makes an interesting case about returning to the Moon, there is always someone else arguing why that would be boring or ininteresting or "we already did that".
I find that quite odd, since there is still so much we don't know about the Moon. If we have the technology, why wouldn't we send someone there to explore and make way for making of a lunar base?
Well, mass drivers should be relatively easy to construct on the moon & can be used to launch fuel and resources for ship construction. Also at least some terrestrial mining and refining techniques could likely be used on the Moon in modified form while we are still very early in zero-g mining and refining necessary for Asteroid resource extraction.
Doesn’t the reduced gravity make a huge difference compared to launching from Earth? Is this not the biggest factor? (Zero expertise here, genuinely curious)
A mission from the surface of the Moon would cost ~3 km/s of delta-v to get an intercept with Mars (and more from there, but that depends on how much aerobraking you can manage).
A mission from the surface of Earth would cost ~13 km/s to get that same intercept - so, yes, it’s considerably more expensive. The majority of that is just making earth orbit in the first place (~9 km/s).
The big problem is that the mission on the moon has to come from somewhere. If you can fabricate your mission entirely at your moon base then the numbers above are accurate. However, if you have to ship stuff in from Earth - well, the Earth -> Moon -> Mars trajectory is more like 17-18 km/s. You’ve lost horrendously.
There are certainly perks to things like off-Earth fueling and assembly, but unless you’re getting a lot of the mass from somewhere other than Earth you’d be much better of doing that in low earth orbit (just from a fuel efficiency perspective, and there would of course be lots of other benefits to being so close to home).
Yes it reduces the gain you get from accelerating in a deep gravity well, so you lose efficiency in your transfer, plus you need to actually get there first. It's a lose-lose situation.
If there is anything to pick up from the moon it makes more sense to deliver it to LEO first and continue from there.
You lose a lot of dv by stopping mid-trip; this isn’t like pulling off at a rest-stop.