Warming Mars (locally)

As to other Mid October Stuff I Missed, heeeere's (or waaaas) Sabine H. She mused about terraforming Mars. It looks a lot like we, er, can't terraform Mars. But we can get part of the way there.

If this seems like a repoast ... yeah, I had a post up, 8 November. I moved most of it the next day to a DuPont / Murphy roast. I am hereby [18 November] deleting the original and rethinking the remainder.

DuPont and Murphy were saying that a shielded Mars (if the DuPont-Murphy shield will work which it won't) would get to Earth's unit of pressure (1 bar) in a "Gyr" - a biiiillyun years. By which time our main-sequence star has made of Earth, Venus II; with or without gerbil worming. So how to hurry it up?

Sabine digs up a 2018 article about, hey, by heating the polar caps. That would get the air pressure to 0.2 bar - in theory. (0.2 bar of CO₂ would also kick up the overall temperature by 10 K, which I am calling out as "not worth it".) The Martians meanwhile are taking that away by compressing it for local plantgrowth but, hey; easier. DuPont and Murphy therefore must resort to dropping comets and other volatile-heavy iceballs onto here because why not, we're already full gonzo.

Among Casey Handmer's [11/17] Starship recommendations was, indeed, for warming Mars - with a mirror from SML2. [UPDATE 12/13: By the long, Lagrange halo - so I assume. I'd prefer high polar.] Pace Handmer, wherever this array goes, I recommend Mars itself for launching and maintaining it all. And would they even need the rocket's reusability? Low g and low ρ mean: the rocket doesn't need be built for endurance (so much). Send up the rocket(s) into and disassemble them at their spaaace destination.

Sabine further mooted the aerogel idea: warm the surface directly (so locally) so that plants (well, algae and maybe mosses) can grow outside the manmade habitats. I wracked my brain, here, to see the point; like, maybe Elon wants a Hanging Garden like they had in Babylonia Assyria, to show off to his next wife. Although: it may do as a daylight carbon-scrubber for the colony. And it doesn't even need that magnet.

Overall: Mars is not getting terraformed within the next million (with "M") years by the resources currently available on Mars. Parts of it, tho', might work better.