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Mars Colony Prize

marscolony.marssociety.org

65 pointsaunty_helen53 comments

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This is a fun dimensional analysis problem.

I'm going to start with food energy. Leaving aside actual nutrition.

1000 people * 2000 kcal per day = 100000 watts carbohydrates (basic energy intake)

100000 watts / 60% = 160kw(raw vegetation) (40% food waste)

160kw / 5% = 3200kw(light) (conversion efficiency from light to food ~5%)

3200kw / 40% = 8000kw(e) (electrical energy to light for LEDs)

8000kw / 40% = 20MW(th) (thermal energy to electricity, carnot limit)

So you need to have a 100% duty cycle 20MW(th) reactor just to supply the lighting for producing food energy, if you're trying to be self sufficient.

You can do other, even more exciting problems for the other key resources. I'd guess that the water cycle and the entangled oxygen cycle would be interesting, as well. Also you can work out the positive energy coefficient of using the hydrogen split out of the water to power a sabatier reactor and produce methane. I can tell you already that the energy budget for this colony would be challenging in itself.

Edit: added more specific units - part deux, corrected off-by-ten error (off-by-one-zero ?)

I don't think we should assume LEDs for lighting.

High quality optical fiber can transfer sunlight with a degrading rate of 10%/km [0]. Light can be farmed on the surface from a larger surface area that it will be projected onto in the farm. Is the sunlight on mars incapable of growing plants? This process would remove the need of generating 2MW of electricity.

[0] https://computer.howstuffworks.com/fiber-optic2.htm

This came up last discussion. It's actually easier on mars to do completely artificial lighting than concentrate, since the concentrators need to be about 3-4 times larger in area than the farmland would be on Earth, and are thus extremely bulky. Unless you can produce optical quality mirrors in-situ, it's probably easier to ship LED arrays.

Plus you don't have to clean the dust off your reflectors if you've just got a whole self-contained system underground.

With LEDs you can focus your output on photosynthesis-friendly wavelengths and collect in a wider spectrum, no?

Agreed; these guys [1] are developing concentrated solar for a lunar regolith melting application.

And the high-quality fiber can be made in orbit [2]...

[1] https://www.lpi.usra.edu/meetings/leagilewg2008/presentation...

[2] https://www.iss-casis.org/blog/taking-zblan-optical-fiber-pr...

The Moon is a lot closer to the Sun than Mars, and you have to remember that EM radiation falls off with the square of the distance. Mars is unsuitable if you need to rely on solar power alone, especially for concentrating and piping light to grow crops.

Whilst using fiber optics to transport the light is a nifty idea, like you mentioned, you have to 'farm' the light on the surface. So that means bringing collectors, making them sturdy enough for the winds and then also going 'outside' to clean them. Might be easier to bring LEDs and something nuclear that also provides a lot of waste heat you can use.

However, if you did user fiber you end up with a light source that's there about half of the time, but plants can grow better with more sunlight. I'm no expert on hydro/LED factory farming so I'll stop there but I'm sure anyone who has grown cannabis would be able to tell you of the advantages to a light source that's highly configurable.

2000 kcal/day is about 100 watts. You should start with 100,000 watts of carbohydrates rather than 10,000. (I'm guessing that your eye skipped a zero and you carried the error forward; it's an easy mistake to make.)

Absolutely correct, good catch! Points to one of the errors that dimensional analysis can't catch.

The natural fit here is a naval nuclear reactor. For example, the A4W reactor on a Nimitz-class aircraft carrier puts out 550MW(th), and of course it has a continuous 100% duty cycle, and 20 years of operating time before requiring refueling. For slightly less overkill, an S6G reactor from a Los Angeles-class nuclear sub puts out 165MW(th), and is substantially smaller and lighter.

Of course, this raises some thorny issues around potential launch failures spreading radioactive material over a large area. This is already a consideration even with the little RTGs that NASA launches for rovers.

I'd expect that's about the size of the problem. Putting an aircraft carrier on mars, but with the carrier deck used to grow food, and the "propulsion" energy going to electrolyse and feed forward into the sabatier process.

Give it 3-5 of the A4W reactors for "a year between transit windows" redundancy, and you're starting to get into the ballpark.

Putting a pair of $13 billion dollar, 110,000 ton nuclear vessel on mars would "only" cost $110bln. A steal, really, when you think about it.

It would cost a lot more, that’s just the cost of lift raw tonnage of the carriers themselves. You also have to lift the machinery to assemble and maintain them, spares of pretty much everything, and the cost of developing and lifting all of that. I think we’d all be looking at the “modest” billions inflate into enormous trillions before we knew it. Of course if it actually worked it would potentially be worth it.

The natural fit here is a naval nuclear reactor. ... Of course, this raises some thorny issues around potential launch failures spreading radioactive material over a large area. This is already a consideration even with the little RTGs that NASA launches for rovers.

Counter-intuitively, a nuclear reactor has lower radiotoxicity risks in case of an explosion during launch. Before a reactor reaches criticality for the first time, it doesn't contain any highly radioactive materials. It's only as radioactive as its uranium fuel. Uranium has a long half-life and corresponding low radioactivity.

Plutonium 238, used in RTGs like that in the Mars Science Laboratory, has a half life of 87.7 years. Uranium 235 has a half life of 704 million years. Neglecting differing relative biological effectiveness of radiation for the moment, that means that the plutonium 238 in RTGs is about 8 million times more radioactive, kilogram-for-kilogram, than the uranium 235 in a reactor's fuel.

The Mars Science Laboratory carried 4.2 kilograms of plutonium 238 (4.8 kg of PuO2):

https://www.nasa.gov/pdf/532433main_FIN%20MSL%20Launch%20Nuc...

It could have carried 33.7 million kilograms of U-235 for roughly the same radiological risk. Or, realistically, missions could launch with reactors designed for a few tens of kilowatts to megawatts and the maximum radiological risk would be much smaller than with RTGs. At least so long as the reactor attains first criticality after the risky launch phase.

Really interesting point!

Since nuclear reactor is unfortunately a tainted term, maybe we just need to rename it to something more technical, like RTG. Space-worthy Inert Radioisotope Power Plant?

> The natural fit here is a naval nuclear reactor.

As addressed in some popular science fiction, Robinson's "Red Mars" has the first mars colony outfitted with what is described as basically a nuclear submarine reactor. To the extent that they describe it as a "Rickover" class reactor.

The idea that 1000 people can be largely self sufficient on Mars is laughable, unless we make unrealistic predictions about where tech will be.

For one example, a village of 1000 people would clearly have newborns. If newborns are avoided then the colony isn't real self sufficient. Launch windows to Earth are wide enough, and travel time is long enough, that sending pregnant women back to Earth is probably not a good idea. It's inadvisable for pregnant women to ride roller coasters, much less enter Earth's atmosphere. The birth will have to be on planet. The colony would need to have OB-GYNs, atleast one pediatrician, nurses, infant care specialist, teachers, janitorial staff for these facilities, administrator staff for these facilities. Mars level gravity births are uncharted territory, and we have no clear idea what complications can arise from it. Easily 2-4% of the population would have to be dedicated to the inevitability bringing in children and taking care of them. Do the children count towards the 1000?

There are enough big problems with being humans that require specialist that 1000 is just not enough, unless you assume unrealistic labor cuts in some areas such as farming, construction, mining, manufacturing, etc.

We clearly don't need an entire hospital and school system to handle children. Yes, the infant mortality rate would surely be high compared to our own, especially with the effects of stress and lower gravity, but a few doctors should be enough to handle basic birthing and the occasion C-section. People managed for thousands of years with much less. As for teaching, I'd expect a more communal model, with less structure and dedicated staff per student than the American system. Parents would likely be much more personally responsible.

What if all doctors die due to a catastrophy? Will we send 10 more doctors to Mars for children waiting to be born? Is this ethical?

Multi-disciplinary studies would likely be mandatory for the initial colonists. “Field medic” training will ensure a sufficient number of colonists could deliver babies and manage cases which required non-specialty medicine. Much like it was during other periods of outward-expansion when your local grocer or saloon owner doubled as a medic (in some case probably the medic).

I don't think a field medic level of medical training will be enough to handle the complications involving living/birthing/growing in reduced gravity.

The effects of reduced gravity are largely an unknown. It could range from minor physical alterations to crippling disabilities. We won't know until mammal trials. Due to the cost it's likely the mammal trials will be human.

It's possible extra medical staff could have other jobs, but professional doctors will be a requirement of the population.

> managed for thousands of years with much less

Well, on a planet which is basically benign and with high rates of infant mortality

I don't see your argument- you say 4% of the colony would be required for child-rearing duties (so, 40 people, which seems a bit high, but whatever) and posit that as a fundamental barrier? There's still 960 (adult) colonists left over, and it's hard to see how 960 is a less tenable number than 1000.

More generally- sure, there are well over a thousand specialist jobs that make our Earth-bound economy go. Probably more like millions. But that economy builds way more than is required for self-sustainability. The Martian lifestyle is necessarily going to be much more spare; so there's your "labor cuts."

You really believe out of 1,000 people, only fourthy will fuck?

You must be living in a monastery.

I think you're confused by what "child-rearing" means: it is the process of raising children, which includes education and specialized medical care. That is very different than "child-having" or "child-bearing."

If they put their teeth in it might be fithty!

Humanity managed to get this far without specialists in every conceivable field herding us the whole time. I think our expectations need adjusting to the sparser/harsher realities of what an early extra-terran colony would look like. In shared living situations (dorms, apartments, families etc) there is generally a division of shared labor so that the whole unit can exist. Sending people with the sole purpose of functioning as a custodian is wasteful and preposterous. As is administration staff for obgyn's. Or, for another example, what good is your HR department if the habitation section of the colony experiences explosive decompression?

Humanity did all of that on a planet every generation of organism evolved to thrive on for billions of years, not a completely hostile environment. All of our ancestors, going back to protoplasmic goo evolved on one planet. All of our mammalian ancestors evolved just on an incredibly narrow window on or near the surface of said planet.

Maybe we won’t need all of our current specialists, but we’re going to need rafts of new ones. You’re also making the “Golgafrincham” mistake when you arbitrarily dismiss existing specialties. It would be a shame for our first colony to die from a disease contracted from the proverbial “unexpectedly dirty telephone.” Having dedicated personal to keep th place clean might be one of the more essential jobs for all we know. HR might be another essential, or something similar unless you want that explosive decompression to have been the result of sabotage because of co-worker conflict.

Well, there's always contraceptives.

Importing human mass from mars is not really self sufficient.

1. The website estimates $500/kg for Earth to Mars, but that number has to go significantly up for human cargo. It could easily be $250k to ship a human if cargo weight is $500/kg. The math works out that replacing the population would cost $250M per rotation. It's probably easier to have kids, even if 4% of the population is dedicated to the task.

2. Finding colonist that will be psychologically prepared to not have kids will be significantly harder than not filtering on that variable. This is the type of thing that can weigh heavy on the mental health of colonist.

This is a colony on a frontier, life will not be easy.

We can't just teleport a functioning city to the surface of mars, the first few waves will be hard, as it always has been in the history of human exploration.

This strikes me as a mentality born of a dying civilization.

If the goal is a thriving and permanent Martian colony, the production of children should be _the entire point_ of the operation, and it disturbs me that this isn't intuitive.

Long-term, sure that's the goal; it's not self-sustaining otherwise. But short term, there are huge benefits to having every member of your colony be a productive adult. So ship in 25 year olds, ship out babies and people who've become unable to work.

I'm unsure it's a wise decision to send infants into null gravity for 3 months.

> Each contestant will need to submit a report of no more than 20 pages

> Reports should be in pdf form and use 12 point Times typestyle, 1” margins.

A 20-page report at 12-point font isn't very much- an average college student has likely prepared longer papers. It sounds implausible that one could pack enough detail into that to make a substantial and novel case for a Martian colony design.

Don’t use letter, use A4, but maybe A1 is an even better option. Pushing the envelope in all sorts of ways.

Also, the CFP is strongly hinting at what buzzwords a winning paper needs. (Robots! 3D printing! Exports!)

Given the paper parameters and this strong hinting, I suspect they’re going to attract a lot of very handwavy and not very serious papers.

For example, one of the requirements is to make steel on Mars. (Why you would do this with only 1000 people, it doesn’t say.) No one wants to say, that we’ll have humans strip mining iron ore (we don’t even know where such veins exist), so someone will say something about 3D printing up a robot smelter that collects iron from dust in the wind, and spits out I-beams that are a special Martian alloy that makes shipping them back to Earth via a railgun cost effective.

That does sound very cool though. Except considering the poor city block on the receiving end of the I-beam.

>3D printing up a robot smelter that collects iron from dust in the wind, and spits out I-beams that are a special Martian alloy that makes shipping them back to Earth via a railgun cost effective

Just picturing this is great, sounds like a winning proposal to me.

I am halfway tempteded to write this up.

Possibly more interesting than the competition is the link to the Mars Papers[1], a "number of papers, including preliminary plans for Mars colonies and their necessary subsystems"

[1]http://marspapers.org/#/papers

Whoever wrote these guidelines doesn't even understand Earth economics, let alone interplanetary economics.

"So why did you move to Mars?"

"I won the Mars Colony Prize, so it seemed like the logical next step."

How do you reject MWs of waste heat in a near vacuum?

Insert metal rods into the mars's crust to dissipate the heat. I don't even think they have to be that deep.

ground?

Just why. I happen to enjoy living on planet Earth. Going to Mars has always sounded to me like an excuse to continue trashing the perfect planet we already have. Of course in that scenario it becomes inevitable to colonize Mars. But god what a sick unspoken premise that is.

No matter how much we trash Earth it is going to be easier to Terraform it back than making Mars possible to live on.

It's okay to ask why. Let's see, because if we get hit by a giant asteroid we would have a way to survive. Because we could learn something about physics, biology, cosmology, chemistry, psychology, etc. Because curiosity. Because there's a whole universe out there waiting to be discovered and we have to start somewhere.

I don't think anyone thinks your premise is valid though.

That premise only holds if we can live without Earth’s support, and frankly outside of science fiction and people without enough scientific education to know better, that’s not happening in the lifetimes of anyone having this conversation, or their children, and probably grand and great-grandchildren. We’re still a ways from being able to live off Earth with suppport from Earth, never mind sustaining the race indefinitely without Earth.

If we want to get the chance to add some real redundancy to the species, we’re going to have to need a functional Earth for the foreseeable future.

We've had astronauts in the international space station for 18 years (with regular supply shipments from Earth) so we're definitely capable of living off Earth with Earth support.

Since we're making unsubstantiated claims, here's mine: humanity will have a self-sufficient (given raw material inputs such as exist on Mars or the Moon) colony within 100 years.

Only if there’s a way to make it pay, and pay a lot.

Seriously. Colonization has never been about “redundancy” or “curiosity”, it’s always been driven by economics.

Those astronauts spend less than 216 days on that station, and require extensive physical therapy to recover (which they never fully do) when they get home. They’re also not a sustainable population, even with supplies and reinforcements from Earth. The longer they spend up there the more their long-term health suffers, and there’s no reason to believe that they could survive for years, never mind breed and sustain a population even with supplies.

Pointing to the ISS as an example of how close we are to self-sufficient colonies betrays a total lack of comprehension about the challenges such an endeavor faces.

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