14 ms·

Engineering Habitats for the Moon and Mars

96 points by ggcdn 9y ago

nickparker 9y ago
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.
- CapitalistCartr 9y ago
  Probably should be meters per second.
- valuearb 9y ago
  Yea, in space it's 10 km/sec. My guess is that it's still many m/sec by mars surface.
- VLM 9y ago
  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-you-fall-on-the-moon-without-injury https://space.stackexchange.com/questions/4678/how-far-can-y... 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-you-fall-on-the-moon-without-injury https://space.stackexchange.com/questions/4678/how-far-can-y... 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.
- ridgeguy 9y ago
  From a 1969 paper titled" The Meteorite Flux at the Surface of Mars". [1] The abstract says that Martian meteorites having a mass greater than 1 metric ton hit the surface with essentially their space velocity, undecelerated. Those with mass less than 10 grams hit at terminal velocity, whatever that is for Mars. In between, I suppose there's a continuum of impact velocities depending on the mass. [1] http://adsabs.harvard.edu/full/1969PASP...81..399D http://adsabs.harvard.edu/full/1969PASP...81..399D (paywalled, but they show you the first page with the abstract, which tells the tale)
valuearb 9y ago
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.
- stcredzero 9y ago
  It could be quite moderate. Teleoperated "robots" ("Waldoes" more properly) are just going to get better and better, as will AI.
- QAPereo 9y ago
  That’s certainly very humane of you, but also wrong. http://www.sciencemag.org/news/2015/05/space-radiation-may-damage-astronauts-brains http://www.sciencemag.org/news/2015/05/space-radiation-may-d... 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 9y ago
    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.
    - 9y ago
avar 9y ago
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.html https://www.space.com/21813-mars-one-colony-space-radiation....
- maxxxxx 9y ago
  If they are chain smoking alcoholics in addition you also won't have to worry about their mental state ')
  - stcredzero 9y ago
    So the first Mars colony is going to be like an early 20th century writers retreat?
    - bsder 9y ago
      More like 18th century America ... (Not actually joking ... 18th century America consumed very large quantities of alcohol and tobacco).
- deleted 9y ago
  [deleted]
- jpatokal 9y ago
  Actually, the friendly article doesn't even mention radiation: their designs are built around internal pressure, thermal differences and micrometeorite protection.
hsnewman 9y ago
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.
- MikkoFinell 9y ago
  Yeah in his TED talk he also went into some detail about how easy it is to control the atmospheric pressure in tunnels. The boring technology is just too obviously synergistic with all concerns about habitats on Mars.
- semi-extrinsic 9y ago
  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.
  - c22 9y ago
    If he wanted to send existing boring tech to Mars he wouldn't have to start a boring company to advance the state of the art. He could just buy an existing product and start figuring out ways to launch it.
    - sithadmin 9y ago
      I can't tell if this is serious criticism or an attempt at irony. Pretty much all the Boring Company has done so far is buy existing products.
      - c22 9y ago
        I'm not being ironic or obtuse. This company is barely a year old, I suspect the improvements alluded to will take many decades to perfect. Starting with the existing state of the art and attempting to become a profitable earthbound venture is not an absurd opening strategy for meeting this goal. Musk has stated: "I do think getting good at digging tunnels could be really helpful for Mars. For sure there's going to be a lot of ice mining on Mars, and mining in general to get raw materials. You can build a tremendous amount underground with the right boring technology on Mars. So I do think there is some overlap in that technology development arena."
boznz 9y ago
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 9y ago
  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.
nickff 9y ago
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
jlebrech 9y ago
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.
vannevar 9y ago
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-InflatableHabitation.pdf http://www.nss.org/settlement/moon/library/LB2-303-Inflatabl... https://er.jsc.nasa.gov/seh/gotomoon.html https://er.jsc.nasa.gov/seh/gotomoon.html
elihu 9y ago
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.
aerophilic 9y ago
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-could-be-home-moon-colonists-ncna813396 https://www.nbcnews.com/mach/science/gigantic-lava-tube-coul... I think something around this approach is the way to go.
perilunar 9y ago
psf, °F, inches, mph, feet, psi, pcf — What a mess. Do structural engineers seriously still work in imperial units?
- ggcdn 9y ago
  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
ggcdn 9y ago
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."
JoeAltmaier 9y ago
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.

96 points by ggcdn 9y ago

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.

CapitalistCartr 9y ago
Probably should be meters per second.
valuearb 9y ago
Yea, in space it's 10 km/sec. My guess is that it's still many m/sec by mars surface.
VLM 9y ago
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-you-fall-on-the-moon-without-injury https://space.stackexchange.com/questions/4678/how-far-can-y... 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-you-fall-on-the-moon-without-injury https://space.stackexchange.com/questions/4678/how-far-can-y... 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.
ridgeguy 9y ago
From a 1969 paper titled" The Meteorite Flux at the Surface of Mars". [1] The abstract says that Martian meteorites having a mass greater than 1 metric ton hit the surface with essentially their space velocity, undecelerated. Those with mass less than 10 grams hit at terminal velocity, whatever that is for Mars. In between, I suppose there's a continuum of impact velocities depending on the mass. [1] http://adsabs.harvard.edu/full/1969PASP...81..399D http://adsabs.harvard.edu/full/1969PASP...81..399D (paywalled, but they show you the first page with the abstract, which tells the tale)

valuearb 9y ago

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.

stcredzero 9y ago
It could be quite moderate. Teleoperated "robots" ("Waldoes" more properly) are just going to get better and better, as will AI.
QAPereo 9y ago
That’s certainly very humane of you, but also wrong. http://www.sciencemag.org/news/2015/05/space-radiation-may-damage-astronauts-brains http://www.sciencemag.org/news/2015/05/space-radiation-may-d... 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 9y ago
  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.
  - 9y ago

avar 9y ago

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.html https://www.space.com/21813-mars-one-colony-space-radiation....

maxxxxx 9y ago
If they are chain smoking alcoholics in addition you also won't have to worry about their mental state ')
- stcredzero 9y ago
  So the first Mars colony is going to be like an early 20th century writers retreat?
  - bsder 9y ago
    More like 18th century America ... (Not actually joking ... 18th century America consumed very large quantities of alcohol and tobacco).
deleted 9y ago
[deleted]
jpatokal 9y ago
Actually, the friendly article doesn't even mention radiation: their designs are built around internal pressure, thermal differences and micrometeorite protection.

hsnewman 9y ago

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.

MikkoFinell 9y ago
Yeah in his TED talk he also went into some detail about how easy it is to control the atmospheric pressure in tunnels. The boring technology is just too obviously synergistic with all concerns about habitats on Mars.
semi-extrinsic 9y ago
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.
- c22 9y ago
  If he wanted to send existing boring tech to Mars he wouldn't have to start a boring company to advance the state of the art. He could just buy an existing product and start figuring out ways to launch it.
  - sithadmin 9y ago
    I can't tell if this is serious criticism or an attempt at irony. Pretty much all the Boring Company has done so far is buy existing products.
    - c22 9y ago
      I'm not being ironic or obtuse. This company is barely a year old, I suspect the improvements alluded to will take many decades to perfect. Starting with the existing state of the art and attempting to become a profitable earthbound venture is not an absurd opening strategy for meeting this goal. Musk has stated: "I do think getting good at digging tunnels could be really helpful for Mars. For sure there's going to be a lot of ice mining on Mars, and mining in general to get raw materials. You can build a tremendous amount underground with the right boring technology on Mars. So I do think there is some overlap in that technology development arena."

boznz 9y ago

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 9y ago
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.

nickff 9y ago

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

jlebrech 9y ago

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.

vannevar 9y ago

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-InflatableHabitation.pdf http://www.nss.org/settlement/moon/library/LB2-303-Inflatabl... https://er.jsc.nasa.gov/seh/gotomoon.html https://er.jsc.nasa.gov/seh/gotomoon.html

elihu 9y ago

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.

aerophilic 9y ago

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-could-be-home-moon-colonists-ncna813396 https://www.nbcnews.com/mach/science/gigantic-lava-tube-coul... I think something around this approach is the way to go.

perilunar 9y ago

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

ggcdn 9y ago
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

ggcdn 9y ago

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."

JoeAltmaier 9y ago

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.