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Comment by ChuckMcM | Hacker News Reader

The paper is here: https://www.sciencedirect.com/science/article/pii/S001910352... but it is pay walled.

One of the more interesting challenges in creating self sustaining colonies on other planets is the availability of water. And this is another example of how Mars might provide water in a very accessible way (40% by volume is a lot of water :-))

NASA has already pretty much convinced itself that plants could grow in suitably amended martian soil[1][2]. I haven't seen a paper yet on whether or not there is enough solar irradiation for robust photo synthesis (needed for the production of plant sugars) but one could always add grow lights powered by one of the small nuclear power sources[3].

[1] https://www.nasa.gov/feature/can-plants-grow-with-mars-soil

[2] https://journals.plos.org/plosone/article?id=10.1371/journal....

[3] https://www.forbes.com/sites/jamesconca/2021/12/06/nasa-is-l....

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The thing I don't understand is why aren't we building something here on Earth that is underground designed to be a self-sustaining system. It seems like if we can't figure out how to do it here, we have no chance to do it on the Moon or Mars. Mars is cool as a story but we don't have our sh!t together enough to really try.

It's another planet, you could suddenly create your own country. It's a billionaire's dream.

I like the idea, are there any benefits from starting under ground or could we just do it even cheaper on the surface?

I think some benefits are difficulty (we want to stress test), similarity (we probably build underground on Mars), and a whole lot fewer outside influences (a lot fewer organisms underground).

It's a good question, the whole "Biosphere" project which you can go visit in Arizona which sought to do something like this. It isn't underground, there really isn't much advantage, and there is a whole lot of expense, in building under ground.

So the partial answer is that people are doing this research. Complex interactive systems like this however are very hard to design all at once. One strategy might be to solve individual problems like having a habitat that provides all of its own oxygen and CO2 processing. Then once that is understood have one that can recycle 100% of bio-waste. Then add a long term power supply, then figure out how to make that supply a renewable one. It is a very complex process and each step will reveal new interconnections that need to be dealt with.

If the Biosphere project taught us anything it's there is a huge amount of problems that wouldn't transfer into other environments, and those other environments will also create tons of different nontransferable problems.

While the famous experiment is over, they've not stopped entirely. Three months ago [0], they announced they'd reopen a small portion of it to investigate how they can winnow down from scrubbers to plant based oxygen replenishment.

[0] https://news.ycombinator.com/item?id=28443187

Because that's boring. Once Mars colonies become a real possibility, obviously the missions will be tested on earth before we yeet billions of dollars to another planet and hope it all works. But going through all that work and money solely for the purpose of an Earth bound terrarium is boring. Who would want to pay for that?

Not only is it a profound and fundamental capability if we intend to live off-planet, it's basically the only relevant capacity, conceived broadly (how to manufacture the means for indefinite survival given supplies of matter and energy). It's the universal constructor problem and our present solutions are fragile and primitive. There is virtually infinite room for improvement. How is that boring?

could be useful in case of disasters, if we ever have to bunker up for a long time

You’ve got it right here. If life’s ultimate purpose is to grow, we have a whole solar system we can grow into. Once we solve growth on planet two, we will be vastly closer to other planets, moons, asteroids and habitats. There’s a whole lot of energy and materials right here at this star and a whole lot of real estate that doesn’t require an environmental impact statement. Per aspera ad astra.

regardless of questions of growth or ultimate purpose we need to be able to do this if we want to persist for any significant length of time in any habitat, planetary or otherwise

a truly sustainable civilization can successfully manage its planetary (or ship- or station-borne) ecology and protect itself from threats with advanced technology equally well, and we are wildly immature in both capacities

i think youre putting the cart before the horse here. there is no possibility of a Mars colony without this work happening on earth.

>> obviously the missions will be tested on earth before we yeet billions of dollars to another planet and hope it all works.

That's my whole point. This work is only interesting as a precursor to doing it on another planet. Nobody has any motivation to do the work and spend the money without a direct connection to transferring it to another planet.

Whenever someone says "why don't we just do it on earth first??". We will: but only as the testing phase of an actual mars colony mission.

were we not actively making this planet more difficult to live on I would be a bit more likely to agree but even so there seems to be plenty of motivation

do we not want to be resilient to e.g. solar flares, supervolcanoes, asteroid impacts/nukes/tungsten rods dropped from orbit, on Earth or Mars or anywhere

See the CHAPEA and HERA campaigns

I can tell no one here has any real awareness of the real science literature written on the subject. We are building, testing, and designing things like this all the time. Just in smaller increments. Just last year I met a young scientist who was working on a research base in Antarctica doing various biology studies on plants/animals living in low-light sealed environments... I was headed to the North Pole and she the South.

I know a one-to-one experiment has a grandiose appeal, but NASA and all sorts of other institutions work on this problem in minor steps every day. The step just aren't, on their own, media worthy or very sci-fi-ish. Heck. Antarctic bases and the ISS, and many other science ventures are essentially a testing ground for some of these things on their own.

Thanks for the comment, this is very helpful. Apart from the first sentence.

My apologies if it's condescending, that's not my intent. I wanted to point out that there's a lot of large wild hairs being thrown around, that's all.

You seem to be assuming that a base on Mars or the Moon would have to be a closed system but that is not true.

There are plenty of useful materials on a planetary surface, for example water. There are also many ways to take advantage of a CO2 atmosphere or oxygen from lunar rocks.

Even space stations don't need to be fully closed, for example the ISS is constantly being resupplied.

Heliostats could work too but might be a challenge with the dust storms. At least at first.

What’s the current wisdom on bioremediation of perchlorates? That seems to be the sticking point.

We know on earth that tidal zones have been a hotbed of evolution. I have this notion in my head of creating terraforming equipment (specifically atmosphere and water) that buffers its output and releases it in pulses though a transitional zone. Like a marine fish tank. Say at the bottom of a canyon or partially enclosed space.

This alternating availability of resources should select for more resilient lines.

Archived version: https://archive.ph/unuNw

The link you provided for the paper wasn't paywalled for me, no idea why.

It’s not paywalled. OP probably saw the name Elsevier and assumed it was paywalled, but it’s open access and licensed CC BY.

Exactly this.

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