
Engineering Habitats for the Moon and Mars - ggcdn
http://www.structuremag.org/?p=12389
======
avar
A much more cost-effective way of dealing with radiation on Mars is to
construct shelters out of something that doesn't shield against radiation at
all, then only pick astronauts who are smokers, and send them to Mars without
cigarettes[1].

For the smokers sent to Mars living in flimsy shelters this'll decrease their
lifetime odds of dying from cancer compared to smoking two packs a day and
staying on Earth.

This article like so many others describes designs for Mars habitats that are
optimized for being accepted under NASA's strict safety rules, and it's an
organization run by safety-obsessed bureaucrats.

I predict that once the second space race kicks off in earnest these
unpractical restrictions are going to be quickly dismissed, because NASA's
going to have to compete with e.g. China which'll likely use much simpler
designs because they're realistic about their risk assessments.

1\. [https://www.space.com/21813-mars-one-colony-space-
radiation....](https://www.space.com/21813-mars-one-colony-space-
radiation.html)

~~~
dsp1234
_much simpler designs_

Simpler than a water reservoir and regolith sandbags? The former is required
anyways, since people will need water, and the later is about as simple as it
comes (we use sandbags here on earth all the time for impromptu buildings).

~~~
avar
There's a world of difference between trying to build a house on Mars, and
trying to build a house whose every external wall is a water tank, having that
water tank also be an active water source (as opposed to a frozen block of
ice) is going to be a construction and maintenance / cleaning nightmare.

Even just regolith sandbags are going to suck, instead of just having your
roof be a simple pressure vessel it's now going to also have to withstand tons
of sandbags and water tanks.

And that's before we get to the problem of trying to either ship all of this
extra water mass over, or trying to mine it locally, or the construction
logistics of piling up hundreds of tons of sand.

All of this will be needed _eventually_ , but it's absurd that NASA is trying
to get in the way of Mars colonization by setting these overly conservative
safety requirements which'll significantly hinder initial colonization
efforts.

~~~
Pica_soO
Eh- the structure carrying problem- was kind of answered in your own post. We
regularly build roads out of ice- and ice infused with carbon has the strength
of steel. So frozen beams of water carrying the sandbags it is?

Also - the simple designs have a problem here- they are not easily repairable
with local materials. And as you can see on any airplane- those simple soda
can designs- wear out pretty fast, if pressure changes regularly. So, yeah-
its a simpler design as in - simpler on earth to maintain, but on Mars its
going to blow up like Mark Rodneys Potatoefarm from stress around the
airlocks.

~~~
avar
We regularly build lots of heavy and complicated things, building them on Mars
is going to be a problem. The biggest thing we've shipped there so far is the
size of a small car.

The process of colonizing Mars should be that we realistically look at how
much payload we can send up there, how much it costs, and then we find some
adventurers willing to take risks to go.

I don't think it's unrealistic to say as a first approximation that the first
people to land on Mars can expect a 10% chance of dying by just trying to get
there, and 30% of dying early due to some complications, e.g. radiation
exposure.

Those would have been fantastic odds when the New World was first colonized,
or when soldiers landed on Omaha beach. Colonizing Mars needs to be looked at
like that, not in terms of sending some government employee into a dangerous
situation, as if though they're going to repair some machinery here on Earth.

Instead, NASA views their rules on safety as immutable, and is coming up with
designs for habitats and ships to satisfy those rules, without ever having the
discussion that perhaps those rules are unreasonable given the endeavour.

------
hsnewman
I suspect that the reason Elon is investing in the Boring Co is to send a
drill to Mars to create underground structures cheaply. This would create
structures protected against radiation (and alot of space) relatively easily.

~~~
semi-extrinsic
Sure, a 100m long, 6000+ ton payload made from things that spin around quickly
sounds perfect for launching to Mars! It's only, what, three-four orders of
magnitude larger than anything we've ever sent to the red planet. And it only
requires the power from one gas turbine powerplant running continuously.
Should be cakewalk. And when it breaks (they all do, all the time) I'm sure
spare parts and engineers are plentiful up there.

~~~
YaxelPerez
That's where the BFR (Big Falcon Rocket) comes in. I think Musk said that it
could carry a fully loaded 747 as cargo to space.

~~~
martindevans
If the 6000+ tonne number quoted above is accurate then a BFR is a _very_ long
way from sending one to Mars - I can't remember the precise payload figure but
I think it was around 100 tonnes to the surface of Mars.

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elihu
I think a sensible low-tech way to build a small-to-medium sized mars or moon
structure is to dig a big hole, stack bricks or cut stone to form an igloo-
like dome in the bottom of the hole, and then bury it in dirt with a staircase
to get in and out. The inside can be sealed with an air-tight liner material
and an airlock installed.

The weight of the dirt counteracts the air pressure and protects against
radiation and temperature variation. The bricks provide a rigid compressive
structure to maintain the shape and hold up the dirt.

The liner doesn't have to be particularly strong, just resistant to accidental
tears. Theoretically, the brick dome could be omitted if you can exactly
balance the weight of the dirt with internal air pressure, but that seems kind
of risky (and every time the internal pressure fluctuates slightly, the dome
gets a little smaller as the dirt settles).

The hard parts of this plan are a) how do you get/make thousands of bricks?
and b) how do you do all the excavation and assembly? It would be great if we
could get robots to do the whole thing and have a habitat ready before humans
arrive on the scene, but with current tech a lot of the work might have to be
done manually by guys in space suits with construction equipment. I suppose
once you have one habitat, it's a lot easier to build a second one next to it.

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valuearb
Interesting, succinct read. One thing I liked about it is that it didn't
mention the old bugaboo of radiation exposure. Obviously regalith on the
living structure is going to help minimize that, but the real answer is that
the first mars explorers are willingly going to accept moderately higher
lifetime cancer risks.

~~~
QAPereo
That’s certainly very humane of you, but also wrong.

[http://www.sciencemag.org/news/2015/05/space-radiation-
may-d...](http://www.sciencemag.org/news/2015/05/space-radiation-may-damage-
astronauts-brains)

 _After letting the mice rest for 6 weeks, the team put them through a battery
of cognitive tests, including a task that required the rodents to distinguish
between familiar and novel objects, such as toys. The mice hammered by
radiation were “severely compromised” on several measures compared with an
unexposed control group, Limoli says. Control mice, for example, spent more
time sniffing around a new item placed in their cages than investigating
familiar objects—a sign that their ability to react to novelty was intact.
Irradiated mice, in contrast, spent equal time exploring new and old items,
suggesting their ability to learn and remember new information about their
environment had been impaired._

Talk of mars colonization is riddled with myopic assumptions about something
we barely understand. Focusing on those few issues we may have in hand to the
exclusion of the many critical unsolved problems is troubling.

~~~
cptaj
They can just wear a helmet. Lead lined balaclava?

They also mention that is not a showstopper and that it can potentially be
countered with entertainment and exercise.

It also remains to be seen what the effect is like on humans. Might be
negligible on a mars trip.

~~~
MikkoFinell
I believe the thickness of lead required for any significant protection would
make the weight of the helmet unreasonable. Unless the exercise you mentioned
consist only of weighted neck curls.

A more realistic approach to mitigating the issue is in my opinion to have
rotating crews. They would spend most of their time in underground shelters,
and only some minor fraction of their time doing surface work. Advances in
medicine, specifically in regard to cancer, along with minimizing exposure
time, is what I believe will make the risk low enough to be within acceptable
bounds.

~~~
logfromblammo
At 38% Earth's surface gravity, you might need to wear lead clothing all the
time anyway, just to keep your bone strength and muscle tone.

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nickff
If you are interested in this subject, I highly recommend Andrew Geiszler's
presentation to the 18th Annual International Mars Society Convention (titled
"Living, Working & Growing in Glass Houses: Construction Methods for a Martian
Colony"). He gives a very interesting overview of materials and design
considerations.

[https://www.youtube.com/watch?v=faEfgDYCYzU](https://www.youtube.com/watch?v=faEfgDYCYzU)

------
aerophilic
One alternative/something that can be used in conjunction is sealing/building
in “lava tubes”. We have already confirmed that there are some that are quite
large: [https://www.nbcnews.com/mach/science/gigantic-lava-tube-
coul...](https://www.nbcnews.com/mach/science/gigantic-lava-tube-could-be-
home-moon-colonists-ncna813396)

I think something around this approach is the way to go.

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vannevar
The idea of using inflatables for space habitation has been around for a long
time, but was seriously revived by NASA in the late eighties. A group at
Johnson Space Center designed inflatable lunar habitation back then, including
building test articles. And there is currently an experimental inflatable
module on the International Space Station.

[http://www.nss.org/settlement/moon/library/LB2-303-Inflatabl...](http://www.nss.org/settlement/moon/library/LB2-303-InflatableHabitation.pdf)

[https://er.jsc.nasa.gov/seh/gotomoon.html](https://er.jsc.nasa.gov/seh/gotomoon.html)

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nickparker
The quoted top speed for micrometeorites has to be wrong. Perhaps missing a 0?
45 mph is silly low, there's no way Martian atmospheric drag could slow them
that much, let alone the case of the moon.

~~~
VLM
I found the exact source of the falsehood, its from a stackexchange discussion
about theoretical sci fi aspects of lunar sports injuries and if you jumped
down a vertical lunar mineshaft pressurized to 1 atm the lower gravity means
terminal velocity would be reached in about 1 km of falling (handwavy) at
roughly 45 MPH (actually 49 m/s).

[https://space.stackexchange.com/questions/4678/how-far-
can-y...](https://space.stackexchange.com/questions/4678/how-far-can-you-fall-
on-the-moon-without-injury)

a 100+ MPH impact on earth would require a survival capsule too tough for
normal purposes so we use parachutes. However a 45 MPH impact is unsurvivable
if naked but a car like structure for an elevator means you could likely walk
away from a mining accident where your elevator falls down a mineshaft on the
moon. Its likely lunar mineshaft elevators will require little more than
extensive crumple zones in the floor, unlike on earth. Also on the earth
stuntmen require weird inflated balloons to break their fall but on the moon a
terminal velocity of only 45 MPH means something like a ball pit or a
relatively shallow (compared to earth...) water pool would make falls
survivable.

I'm too lazy to run the math to figure out the maximum gravity where a human
could fall from a very far height and hit the ground at less than a survivable
10 MPH or whatever is defined as survivable.

[https://space.stackexchange.com/questions/4678/how-far-
can-y...](https://space.stackexchange.com/questions/4678/how-far-can-you-fall-
on-the-moon-without-injury)

The big mistake of course is the lunar atmosphere is, as an engineering
approximation, 1e-15 atm not 1.00 atm.

In practice its interesting to think about a micrometeor strike hitting a
large structure, given the very low mass and low structural stability of a
random rock chunk vs aerodynamic forces, it would blast clean thru the
ceiling, then shatter and lose velocity very quickly down to sonic range or
perhaps far below. Something like a giant balloon stretched over a tall crater
would be reasonably survivable when hit by a meteor. Decades ago how to repair
the tiny slow leak would be a major puzzle, today its just a boring job for an
autonomous drone. Possibly the assumption in the article is if the roof is
thousands of meters overhead and a meteor breaches the roof, it'll hit a human
in the head at 45 MPH, which is quite survivable if the colonists wear
construction hard hats but not so good out in the open. Sleep with a roof over
your head, even rather minimal, and you probably won't wake up dead, if the
balloon ceiling is far enough overhead.

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boznz
People who live in these will be real pioneers and I don't think there will be
anything glamorous about it (thinking more modern caveman rather than moon
base alpha). I think the people who go will have to be crazy, wreck less and
have a death wish, however I totally encourage them to do this.

I'm a big fan of space, but I don't see me going there until something better
than rockets are invented and all the other many problems are solved so I can
just sit at a nice coffee shop and enjoy the view.

~~~
AJ007
I think a large percentage of time will be spent in virtual reality, making it
less like living in a Siberian prison camp.

Also note, this makes John Carmack's contribution to space colonization
significant.

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jlebrech
all we need to do is bore down and put a lid on top. years later we can make
it more complex.

we could drill a few holes into lava tubes for example
[https://en.wikipedia.org/wiki/Martian_lava_tube](https://en.wikipedia.org/wiki/Martian_lava_tube)
and direct light into it for something a bit more elaborate.

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ggcdn
Note that the title was edited (by a mod?) from my stylised version (oops - I
had used the tweet title) to "Engineering Habitats for the Moon and Mars"
which is actually a subheading within the article. The actual title is
"Structural Challenges for Space Architecture."

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JoeAltmaier
More leverage in adapting existing structures, such as lava tubes and roofing
over meteor-impact cracks and fissures? Much larger volumes at much reduced
construction costs.

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perilunar
psf, °F, inches, mph, feet, psi, pcf — What a mess. Do structural engineers
seriously still work in imperial units?

~~~
ggcdn
Surprisingly, yes! Even in Canada, about 9/10 of the projects I work on are
using these units.

These units are generally much more pleasant to remember and work with, even
despite the code using empirical design equations that require SI units

