this post was submitted on 28 Aug 2024
425 points (99.1% liked)

xkcd

8574 readers
8 users here now

A community for a webcomic of romance, sarcasm, math, and language.

founded 1 year ago
MODERATORS
 

Alt text:

At least they're not alone down there.

https://explainxkcd.com/2978/

top 16 comments
sorted by: hot top controversial new old
[–] [email protected] 4 points 2 weeks ago

Wonder how much willpower they have

[–] [email protected] 5 points 2 weeks ago (2 children)

I dunno. I heard they only brought one set of clothes, and they have to wear those clothes until February without being able to wash them.

Doesn't sound pleasant.

[–] [email protected] 4 points 2 weeks ago

The fact that the initial mission duration was 8 days makes it unlikely this is true, and with multiple cargo missions since then (for example two already this August), it is even more unlikely they wouldn't have received a new set of clothes by now.

[–] [email protected] 4 points 2 weeks ago

Spaceships stink. Common trope in sci-fi.

[–] [email protected] 25 points 2 weeks ago (1 children)

Reminds me of the old Niven stories about asteroid belt-miners, who disdainfully referred to being on the surface of a planet as being at "the bottom of a hole."

[–] [email protected] 13 points 2 weeks ago* (last edited 2 weeks ago) (2 children)

I'm a space nut, and people often ask me about colonizing Mars. And I always think, sure I guess you could, but why? Once you've made it to orbit, make the most of it, why put yourself down at the bottom of a gravity well? Just colonize orbit, asteroids, or small moons. That's where the resources are, and that's where it's easy to move them.

[–] [email protected] 4 points 2 weeks ago

Given the means to process, refine and build in zero g, I'd love to have my own asteroid.

[–] [email protected] 16 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

Humans are very picky. Must have certain amount of gravity, need to see green stuff, can’t handle radiation etc. it’s is as if they were built to be on a specific planet and nowhere else.

[–] [email protected] 9 points 2 weeks ago* (last edited 2 weeks ago) (2 children)

You're totally right, but that gravity, that green stuff, neither of those are on Mars. In orbit at least you get the gravity, rotating habitats aren't that much more complicated than static ones.

I'm not sure if Mars' poison and irradiated soil will ever be useful for growing plants. I'm telling you while it is a similarly sized planet, it's still barely useful.

[–] [email protected] 2 points 2 weeks ago (1 children)

I think we could send robot farmers there to grow some food for the people living in orbit. Maybe low-G carrots could be nicer than the ones grown on earth.

[–] [email protected] 1 points 2 weeks ago

Entirely possible. But hey, in a space station you could have a separate agriculture ring, it may turn out that plants grow most efficiently at some particular amount of gravity, having its own ring would let you experiment, to maximize yield. Also you can use shades and mirrors to precisely control the amount of sun the plants get, even provide them constant sun if that speeds up growth.

[–] [email protected] 3 points 2 weeks ago (1 children)

The presence of water is nice

[–] [email protected] 6 points 2 weeks ago (1 children)

That's true. Local water, even as trace ice crystals, would be easier to harvest than chipping apart a comet in deep zero g. But ultimately, your materials for both construction and life support are going to have to start coming from space, and asteroids and comets are the obvious choice.

The best strategy would probably be to send a relatively small vehicle to the comet (small relative to the comet), something like the power and propulsion core for the new lunar gateway, essentially just a big ion thruster with a bunch of solar panels. This can push the comet into an orbit that swings it by the moon to capture it into an earth orbit. You may need to do some earth flybys to lower the comet's orbit first, so the mission could take years. But to make up for that, comets are huge, and after it's done you have a source of many different materials to work with right here in earth orbit, enough material to last decades or more.

[–] [email protected] 1 points 1 week ago (1 children)

But not all water is useful.

We have a lot of non useful water on Earth in the oceans that has too much salt.

Water from non-Earth sources might contain dissolved minerals at poisonous levels for agriculture, much less human consumption.

And if there's liquid water from a non-Earth setting, there might be some kind of unknown exo-organisms living in it.

[–] [email protected] 1 points 1 week ago* (last edited 1 week ago)

Water from non-Earth sources might contain dissolved minerals at poisonous levels for agriculture, much less human consumption.

Oh yeah, it's practically guaranteed to contain nasty stuff! We're gonna drink it anyway though.

Most of that water on earth that we'd consider "not useful" would fall into the "100% useful" category if found in space. As long as the contaminants have a different boiling temperature from water, you can always boil the water into steam in order to separate it. Or you could also use electrolysis to separate out the hydrogen and oxygen and then recombine then in clean tanks.

These are expensive methods of purification, energy intensive, but solar panels really well with no atmosphere and 24/7 sun exposure, so this is all feasible.

[–] [email protected] 10 points 2 weeks ago

Rorschach: lifts mask, scratches ear