[jacquesm]

Correct, the moon has a lot of aluminum and iron in its composition, once you can put a smelter and forger on the moon you have access to an endless stream of girders and other materials to make stuff out of. That stuff might not be strong enough for space elevator construction but there are plenty of other things you could use it for.

Whether any of that would be economical is another matter.

http://lunarpedia.org/w/Lunar_Aluminum_Production

[kerkeslager]

What's the heat source for this smelter/forger?

[scardine]

The moon has ideal conditions for solar energy harvesting: no atmosphere, no weather...

Since Project Apollo in the 1970s it is known that all the materials needed for manufacturing photovoltaic cells are present in lunar rocks and dust. Not saying it is an easy engineering feat, but the raw materials are there.

[setr]

combine factorio with kerbel space program, and we'll have this sorted out no problem

[Misdicorl]

Large sun focusing mirrors might be sufficient

[raducu]

That sweet Helium 3 nuclear fusion :) . Oh, wait, it would be just wasteful to use aneutronic fusion to smelt metals on the moon. You could probably sell the Helium 3 back on Earth and just use regular nuclear fusion to do that.

[s1artibartfast]

you dont even need a smelter/forger if you want to build a massive space colony at the L1 lagrange point (which the moon elevator would pass through). Just pack the raw lunar regolith into prefab plastic sheeting similar. this is similar in concept to inflatable space habitats with the added benefit of radiation protection and thermal insulation.

https://en.wikipedia.org/wiki/Inflatable_space_habitat

[jacquesm]

The Sun.

[52-6F-62]

Now that idea just makes me think of https://marvel.fandom.com/wiki/Nidavellir

[jacquesm]

I had this in mind:

https://www.alamy.com/solar-oven-huge-parabola-shaped-mirror...