Will plants grow on the moon? | Hacker News Reader

Will plants grow on the moon?

nautil.us

99 pointsdnetesn106 comments

This is cool. I look forward to seeing the results of this experiment. In case you were curious, this is routinely done on the ISS [1] so I don't expect low-g on the Moon to be an issue. The one issue is radiation (which is mentioned) because the Moon is exposed to this in a way the ISS isn't (thanks to the Van Allen belt).

Should this become necessary however, it won't even be an issue long-term. Why? Because you'd grow things underground. There's absolutely no reason to do anything above ground on the Moon. We have pretty strong evidence of ancient lava tubes so there's no need to excavate either.

Ideally, you'd seal a lava tube and put in air and you could live in it with the plants being natural oxygenators.

Long-term you'd probably want to see if you could manufacture growth medium on the Moon from available materials.

[1]: https://gardenculturemagazine.com/growing-hydroponics-in-spa...

From the article, I believe the effects of the radiation are what's being tested. Which is an important thing to know if we want to put people on Mars as it also has a huge amount of radiation and food is heavy to transport.

If we can grow plants above ground, that can free up resources for an underground colony.

> Why? Because you'd grow things underground. There's absolutely no reason to do anything above ground on the Moon

If you grow stuff on the surface and in the sun (with some imaginary window that let the good parts of the sun rays go through, without any of the bad stuff through), wouldn't that be at least slightly more energy efficient, compared to growing stuff underground with lots of strong lights?

The problem with the Moon is the 28 Earth day day/night cycle. It takes the Moon from blistering heat (~250F) to bone-chilling cold (-200F) so anything on the surface has both a cooling problem and a heating problem.

There's no atmosphere so the only way to get rid of heat is to irradiate it away into space or pump it away and do the same thing. Likewise, heating is a big problem and an energy waster as you're irradiating away heat.

Going underground just avoids the heating problem, the cooling problem and the radiation problem. It also avoids the issue of meteor impacts on the surface. Those craters came from somewhere.

Excavation is expensive but it depends on what you're working with. Is it loose? is it hard rock? I don't think we have good knowledge of the geology of the Moon because we'd have to go there and start drilling cores to find out. The presence of ancient lava probably means we'd be dealing with some hard stones too like basalt or granite. But that's just a guess.

Lava tubes, if sufficiently large, just solve so many of these problems.

It's just easier to collect power and produce the light you want to grow somethin gunderground.

Those craters came from somewhere.

NB: most of the visible craters on the Moon are billions of years old, and were created during the late heavy bombardment, 4.1 -- 3.8 billion years ago:

<https://en.wikipedia.org/wiki/Late_Heavy_Bombardment>

There are still constant meteoric impacts on the Moon, most as micrometeroids, though occasionally large enough to be visible from Earth. The one observed here in 2023 likely created a ~12m / 40ft diameter crater:

<https://www.space.com/meteorite-impacts-moon-february-2023-v...>

The larger craters would also likely have survived passage through the Earth's atmosphere, FWIW, so that wouldn't have saved you much either.

A more significant problem for any surface structures would likely be dust launched by human-based rocket landings and launches. Lunar dust does not billow from rocket exhaust, it is launched on a trajectory, probably sub-orbital, and will continue moving at its initial velocity until it impacts terrain or a structure.

This was first clearly realised and demonstrated during the Apollo 12 mission, which landed ~180m / 600ft from the Surveyor 3 unmanned lander. Parts of that spacecraft were returned to Earth, where it was discovered that they'd be sandblasted by lunar dust, largely as a result of the Lunar Module Intrepid's final descent:

<https://www.space.com/4956-lunar-landers-sandblasted-moon.ht...>

So it's probable that most man-made lunar structures would either have highly-resistant exteriors or be underground. And landing zones out of line-of-sight (or parabolic trajectory).

I thought there are some regions in the North Pole that are constantly illuminated. Presumably the temperature is significantly more stable in those regions.

Apparently during part of the year the illumination is interrupted. But they're still lit most of the time.

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

I don't think that is possible. You may be thinking of the bottoms of some craters, which are always in shadow.

Some craters have central peaks, and polar peaks might also be possible. Those should be in (near) constant solar exposure.

The Astronomy Stack Exchange suggests both north- and south-polar locations, near Peary Crater (north) and Shackleton Crater (south):

<https://astronomy.stackexchange.com/a/26110>

> There's absolutely no reason to do anything above ground on the Moon

Is there a reason to do anything below ground? We already aren't doing anything above ground.

Radiation is a serious problem. It tears apart DNA & RNA. Blocking radiation takes lots of material, hence, underground.

That's not a reason to do something below ground on the moon. It would be a reason not to do something above ground, which, as I noted, we already don't do.

I've moved beyond not doing things on the moon. That's so passé. I'm already not doing things above ground (or below ground on Mars) and have no plans for the moons of Venus after that.

Many of us aren't even doing things above (or below) ground on Earth.

You may prefer to do the other thing but I think as a species it's ok to have some off planet outposts. Feel free to not go there, and also don't go to antarctica or anywhere else particularly challenging.

Yes, but it requires said imaginary window.

Underground just requires LEDs and solar panels. Both of which we can make quite cheaply.

Leds, solar panels, and distribution is not cheaper than glass or plastic sheeting.

Could be cheaper on the Moon. The plastic/glass sheeting needs to be vacuum safe and hold pressure in. Plus you need energy anyway for heating (and cooling!), especially for the 2 week long moon nights. Being underground is not only better as radiation shield but also a better/safer controlled environment.

> Ideally, you'd seal a lava tube and put in air and you could live in it with the plants being natural oxygenators.

We've tried that on earth and it doesn't really work. You need a lot of plants and a wide variety of plants.

Living on the moon is a fantasy. It won't happen in any of our lifetimes. Mars is an even greater fantasy.

Living on the moon works, because we can send supplies frequently like we do with the ISS. Meanwhile mars is so far away that anyone who goes there signs up for a suicide mission.

Every single mars mission proposed by musk relies on a pyramid scheme where every round of launches sends more and more people until one day self sufficiency is achieved and the first guy sent to mars will have a chance of returning to earth.

Here's a fun youtube video on just how much it'd take to survive on plant life alone. [1]

Spoilers: Can't be done without a huge amount of vegetation. Algae, on the other hand, can work, but it still takes a boat load of algae for just 1 person.

[1] https://www.youtube.com/watch?v=xWRkzvcb9FQ

> Ideally, you'd seal a lava tube and put in air and you could live in it with the plants being natural oxygenators.

There's a LOT of oxygen on the Moon (basically in every rock). There's effectively no carbon. If you want to grow plants there - you need to take carbon with you (probably in the form of coal you'll burn once there to generate the CO2 needed for plants).

1 person eats about 1000 kg of food per year, which is about 500 kg of carbon. If you grow plants in a yearly cycle you need to sent half a ton of coal for every colonist. The ones born on the Moon too.

This sounds very off. Dried rice is 400 kcal per 100g. That is 500g of uncooked rice per day or 180kg of uncooked rice. What you are counting as "food" is the cooking water being absorbed into it.

Those humans are also producing CO2 so it will have some self-sustainability. The 5% CO2 of human breath is a lot more than the ~0.04% in the atmosphere.

I have no idea how to calculate the steady state or what the losses would be.

How hard would it be to find and de-orbit a carbonaceous asteroid or two?

> Because you'd grow things underground

Is the radiation close to normal light on earth, so that maybe fiber glass tubes could be used to route the light in a controlled manner into underground caves?

Too bad they are going to remain on the surface. Maybe next time they will set up all the hydroponics in a lunar cave. There are shaded areas in craters that supposedly remain a constant 63F (17C) year round.

If the soil has no nutrient capacity, there's no reason to use it. Hydroponics work well enough. I just don't see the case for immersing roots in a medium, where the question is whether the medium would be quite toxic enough to kill them entirely, when roots can grow in air.

> when roots can grow in air

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

TIL

TFA appears to agree with you.

Certainly, apart from light and water and gasses, plants may require certain physical soil properties and nutrients, and possibly other lifeforms to thrive.

Besides elements that should be present, there are elements that should rather be absent; you don't want to grow potatoes in a soil rich in arsenic or lead.

IIRC, most analyzed samples of Moon regolith contain something that plants don't exactly like, but can tolerate. Some selection and / or genetic engineering may be required to produce plants that grow readily on regolith-based soils.

> possibly other lifeforms to thrive.

They certainly require other lifeforms. The vast majority of plants depend on microbes for nitrogen fixation.

This is not correct. Most plants get their N from nitrates or ammonia salts, and only some plants (mostly leguminous ones) use a direct symbiosis with nitrogen-fixing bacteria to produce these from atmospheric N2. Most of the N in natural ecosystems comes from decay of proteins (from vegetable or animal origin), and in agriculture of course it is added as fertilizer.

Is the radiation not similar to the one you get in space? seems like that would be a cheaper place to test the effects of radiation.

Depends where in space. From the article: "the International Space Station orbits within the Earth’s magnetic field, and so it is exposed to much lower radiation levels than the lunar surface".

from the article:

> Growing plants on the ISS is a complex business, and Porterfield says a chief concern is that plant roots depend on gravity to draw water.

So while the radiation might be similar (I'm not sure), other variables are different.

Plant roots don’t need gravity to draw water! Plants use evaporation and the tensile strength of water (yes, really!) to draw water up against gravity.

While that is true, plant roots and stems use gravity to know in which direction to grow (roots down and stems up), so that will cause problems in space.

NASA has succeeded to grow some plants on the ISS, by making them grow towards a source of light (i.e. LEDs), but until now this has worked only for some very low-growing plants, like lettuce and some varieties of cabbage, not for plants with deep roots and high stems.

It should be much easier to grow algae in the absence of gravity, but those are not as tasty as terrestrial plants.

You could probably engineer some palatable food items with algea and mushrooms. I would put my money on fungus as a food source.

I think you are thinking of capillary action, adhesion, and vacuum pressure. Water does not have tensile strength.

Water is capable of sustaining pressures of -140 MegaPascal, or about -1400 atmospheres.[1]

[1] https://www.nature.com/articles/nphys2475

That is still different than mechanical tension.

It's very odd to phrase it as "tensile strength", but capillary action is an expression of surface tension, which is the result of molecular cohesion--two (water) molecules resisting separation. In other words, strength under tension, with measurable stress and strain. With some squinting, you've got tensile strength with elastic deformation.

I think you are right and that is what they are getting at, but it is more a property of the system, not thee material. It is hard to reconcile fluid flow of a liquid with tensile strength.

I’m sure they have considered this and/or doing it already but you’d only need a small centrifuge to simulate gravity for an experiment.

A small centrifuge won't work; you get a strong coriolis effect. A large centrifuge could, but the ISS doesn't have one of those. It would need to be huge to be absolutely sure your data is accurate.

Late to reply back but I’m not sure why that matters when all you are looking for is roots to have enough stimulation to uptake water.

They're also testing the effects of reduced gravity.

How much energy would be required to provide a localized magnetosphere to protect the garden from cosmic rays?

When people think of radiation protection, they think of the magnetosphere. But they really need to be thinking of the atmosphere. There's a reason traveling on a plane gets you a higher dose of radiation and it's not a weaker magnetosphere.

Perhaps a thick shell of water suffices. In the order of meters, perhaps one to four meters. Perhaps combine it with lead, in the order of centimeters, perhaps ten centimeters, then one meter of water would suffice.

Numerous long-duration spacecraft designs incorporate water storage in the outer structure, or a high-radiation shelter within a water storage structure, for just this purpose.

Water attenuates radiation quite rapidly. And has other uses.

<https://news.ycombinator.com/item?id=41646990>

<https://isoe-network.net/publications/pub-proceedings/sympos...>

There will never, ever be such atmosphere on Moon as its on Earth. Too low gravity for example, solar winds would scrub it pretty fast even if you would somehow create it 100% with a snap of fingers.

Its nice dreaming about options but this aint realistic.

We are only talking about "fast" relative to normal planetary timescales.

My understanding is that it would still take hundreds of years for the solar wind to strip away the atmosphere. If a civilisation had the technology to quickly put an atmosphere on the moon, it has the technology to continually replenish the atmosphere as long as that civilisation lasts.

It would never be practical (or a good idea) but a post-scarcity society could pull it off as a vanity project.

Cover your garden with a few dozen meters of rock. In fact, build your base in a cave.

Plants grow in radioactive soil around Chernobyl just fine though.

Those radiation liking mushrooms could be an interesting test for the next batch of plants to the moon. :)

How tolerant are plants to cosmic rays?

This is what the test covered in the article is set to discover.

Seems like solar could easily supply?

Easily, assuming you have solar panels that could survive the temperatures of the lunar night.

You don't absolutely need to put your base somewhere it'll have a night. There's a large mountain chain on Moon's south pole that's in constant sunlight.

Yep and whoever controls that, controls the moon. It’s prime real estate.

All we need is a bunch of potatoes, but don't figure to have a healthy stock of ketchup on board.

Maybe, but if the colonists keep sending video diary messages while talking with their mouths full, I vote we just leave them up there.

BizarroLand wins the award for getting the joke (reference to the movie "The Martian"). Please forgive my taste for very nuanced humor. :-)

Potatoes aren't enough by themselves, you need dairy to hit all the nutritional requirements.

There doesn't seem to be any single food that is alone nutritionally complete, but potatoes are certainly one of the closest... many people seem to do well with just potatoes for a month or two. A few supplements (B12, etc.) would likely allow potatoes to work long term.

you still haven't properly implemented nachos.

Why do you think so?

https://www.snopes.com/fact-check/potato-butter-diet/

Could keep you alive long enough but eventually you'd want some other nutrients.

Maybe there's a joke here that I'm not aware of, but my question was mostly why they think dairy is necessary. I do believe that potatoes isn't enough, but you don't need dairy products.

> you don't need dairy products.

You generally need animal products for B12, but you can use supplements, I think. B12 deficiency can take a year or more to manifest severe symptoms.

In the movie "The Martian" Matt Damon grew potatoes on Mars. Lived off of them and ketchup for a long time, and the ketchup ran out.

lol I wondered how long it would be before someone got it

I thought Musk said some time back that SpaceX was sending people to Mars next year. How did they not already know this?

You can choose any year from the calendar, and there would be a Musk statement that says we'd be on Mars that year.

You might as well ask a fortune teller instead of listening to what Musk has said

Fortune tellers tell you what you want to hear; Musk tells you what he wants to hear, then pays people to make it happen.

The results may be a day late and a dollar short (adjusting for inflation since 1939 or whenever), but Musk did actually get people to build spaceships, and his worldwide competitors there are floundering.

I don't know about that. At the current pace, the turtle is going to overtake the hare.

I don't understand how the metaphor applies.

SpaceX is approximately half of mass launched to orbit, globally, including all other national and international space agencies. They are always free to trip up over Musk's hubris, but this hare isn't resting on its laurels or snoozing during the race — Starship (if successful) will eat the market for the Falcons. Conversely, quite a lot of the turtles (notably Boeing and Arianespace) are indeed resting on their laurels.

Other heavy/superheavy launchers can only catch up with and not surpass SpaceX until Musk disappears for whatever reason; getting past SpaceX without that probably needs a non-rocket launch system e.g. a Launch Loop or a skyhook/rotovator. Suspect only China can organise both investments and streamline the planning permission. Although at Musk's wealth level "buy sovereignty over a 10km wide strip starting on the coast of Mauritania and ending on the east border of Mali" is conceivable so even that's not a shoe-in.

SpaceX being the most competent at their game doesn’t change the fact that Musk’s plans are pure fantasy. My bet is that won’t see any people going to Mars during his lifetime.

Everything he's started or meaningfully invested into has been fantasy when he did that, some of them were turned into reality.

Starship is still interesting even if they don't build a Mars colony. Or a moon colony. Or low orbit hotels. Or asteroid mining.

I think that even if they send some test missions on the Mars launch window 2 years from now, plenty will go wrong, and the same for the next window 4 year's from now. If Musk hasn't made too many political enemies to continue by that point, then they probably have a reasonable short for a crewed mission in the launch window after that, 6 years from now.

If SpaceX doesn't have a demonstration Sabatier process plant that fits into a Starship by the beginning of 2028, they've stopped caring about going to Mars. ISRU is too important, so even if they actually send any ships that way, without a Sabatier plant they would be no more relevant than the trans-Martian Roadster.

I wouldn’t bet against you. He has only 27 years left until he is 80. Maybe he will get 100 years old, maybe he will get a heart infarct next year.

But this will make the matter more urgent for him, there is no reason for him to take it slow and steady, the opposite, he will push Starship hard. The next few years it will be vital for NASAs Moon landing. And after establishing a fuel depot in Earth orbit, which sounds science fiction now but is the plan for Artemis III, there will be whole new possibilities.

Truth doesn't matter to him as long as it brings hype.

https://elonmusk.today

Doesn’t seem like this is updated when a goal is reached?

For example:

> 10,000 Teslas a Week [Link] 2,615 days since Elon Musk promised producton of 10,000 units a week by the end of 2018. (8/2/2017) "What people should absolutely have zero concern about, and I mean zero, is that Tesla will achieve a 10,000 unit production week by the end of next year." Elon Musk, quoted by Giovanni Bruno in The Street

They are producing now around 2 million cars a year which is four times 10K a week.

———————————

> Teslas Are Boats [Link] 1,703 days since Elon Musk advised consumers that Teslas can safely function as a boat for short periods of time. (1/31/2020) "A Tesla works as a boat for short periods of time, as an electric car has no air intake or exhaust to block & battery/motor/electronics are water-sealed." Elon Musk in a Tweet

I mean, yes? Everytime there is a flood people are astonished about this. This videos from 5 days ago:

https://www.youtube.com/shorts/CEUq8PUAPWk

You could nail him on a technicality in that it is a submarines, but come on:

https://www.youtube.com/watch?v=UBwmAMNI9qk

———————————

> Super Fast Starlink [Link] 1,315 days since Elon Musk promised Starlink customers their speed would double by the end of 2021. (2/22/2021) "Speed will double to ~300Mb/s & latency will drop to ~20ms later this year" Elon Musk in a Tweet

Some customers are hitting that:

https://www.reddit.com/r/Starlink/comments/1fh303p/live_in_t...

Good question.

I had assumed that statements are added only after they've become false, so the 1st and 3rd of your examples would have been added on or around 01.01.2019 and 01.01.2022 respectively.

As to boats vs flotsam (the 2nd), I've already used up my thinking-about-Musk budget for the next couple of years, but since you've nerd-sniped: floating Teslas weren't cargo, so they're not flotsam; they weren't deliberately thrown overboard, so they're not jetsam; and as they haven't been abandoned, they're not derelict; but as I doubt they can navigate, unless they're displaying vertical lights or balls they're not conforming boats not under command, either.

Lagniappe: https://en.wikipedia.org/wiki/Ghost_ship#Historically_attest...

EDIT: closer to the boat/not boat boundary: https://www.flightglobal.com/airframers/us-regulators-given-...

EDIT2: so I watched the YT short; that's not even a boat, that's just a car wading.

Sorry, "boat" had left me imagining (1972) https://www.youtube.com/watch?v=vb9hh65iCik

Maybe he did, but not recently.

He posted this several days ago: https://x.com/elonmusk/status/1837908705683059166

He also baked in an out for himself. Now, if Kamala Harris wins the Presidency, he can say that she prevented from totally doing the thing he said he was going to do.

Sending humans to mars is difficult.

I find it interesting that he thinks being nuked every two years is a benefit to being so far from an out of control Earth. I’ve seen BSG and know nukes can fly in space.

Stealth is hard in space. Not actually impossible when the opponent is a colony with the population of approximately Luxembourg, especially for a mostly-unpowered payload that doesn't need to be kept at 20 C the whole time, but it is hard.

Nukes can fly, but for that transit you get far more opportunity to shoot them down. Bigger issues are "why are they bothering to target Mars, there's not much there" and "oh wait, that was a great place to stick a second-strike capability, Outer Space Treaty LOL, so of course it's being targeted".

5 unmanned mission in the 2026 launch window, manned mission to follow in 2028 if the unmanned are successful is the most recent statement (though some reports garbled that into all 6 happening by 2026.)

I'm not saying 5 successful unmanned missions are impossible in 2 years, but I think Elon may have slightly underestimated the difficulty of the task. There is a lot of stuff left to develop still and very little time to do it.

Elon is not great at estimating how long tasks will take. He originally promised that full self driving would be complete by 2018.

Note that its not so much five in two years as five in a narrow window that opens in two years; they’d be near-simultaneous missions, on whose success would depend the manned mission when the subsequent launch window opened.

But, yeah, Musk timelines are not something I would put a lot of faith in.

"Next year" in Musk years means they have at least 6 years to get it right.

Snark aside, SpaceX may be thinking of MREs instead of growing food.

I think he said an unmanned mission in two years and humans in 4 or 6 years.

And you have to at least double any Musk time estimate.

Vastly under-estimating the magnitude of the task is how the crazy things get done.

Christopher Columbus wasn't unique in believing the world was round, he was rather unique in his vast under-estimation of the distance to Asia. The only reason he survived is dumb luck that the Americas were about where he thought Asia was. All of his doubters were correct that he would die before reaching Asia.

Of course, this way, way far down the list of reasons not to take Christopher Columbus as a role model.

Could SpaceX make a Starlink that revolves around the moon and could transmit imagery back to Earth?

What you are describing is a satellite.

Well, then there’s the beaming back to Earth. Maybe that’s easy…I wasn’t sure. Thx for the snark, tho.

No I get it. The words we use to describe things change over time with what we are exposed to. Starlink made satellites sexy again.

...and there have been a few satellites in lunar orbit, and even a private/commercial orbiter (capstone) recently https://www.advancedspace.com/missions/capstone/

Reply on news.ycombinator.com