Colonization Discussion Thread (split from SpaceX)

[tater]

One, Lunar concrete is a thing (I used to go to the "Space '_year here' " conferences of civil engineers (Space '90, Space '91, etc), and I saw many talks on that. That said, I was assuming burying a hab that is brought, in pure, loose regolith. Clearly making regolith more dense helps. I would assume the density difference with depth is related to compression of the material more than anything else. The engineers were also concerned about small meteoroids, as I recall, certainly a different issue.

Two, DSG is a different thing, and honestly any lunar facility is, since they will NOT be colonies. Not ever. If people don't live their entire lives there, and have children, it's not a colony, it's a base. I was thinking more towards notional Mars colonies, since the rad environment is similar on Mars. For that, the idea of a flare vault makes less sense, honestly. I'd rather have a permanent colony have most people living/sleeping in a facility where they ignore flare events entirely if inside, and the impact on the colony is only to not go on EVA during such an event. Remember that I'm thinking in terms of lifetime exposures where the people in question---or their children---spend their entire lives in those facilities.

Hence the desire to drop the exposure to the lowest possible. Take Mars. Any activity outside, or in parts of the habitat that have higher exposure (due to having windows, for example) bumps exposures a little, but not worrisome if your baseline exposure is lower.

I think that's why they aim for zero inside, since workers will presumably have decent numbers of hours outside at higher exposures.

Edited February 16, 2018 by tater

[PB666]

7 hours ago, kerbiloid said:

?
It works for reactors and  nuke vaults, why shouldn't for lunar bases?

 

Fall out shelters are designed to protect from x-rays and gamma radiation, protection is generally heavy metals like lead. The particle type is photons and relatively low velocity alpha particles. Alpha particles are 4 times as heavy as protons.

True GCR are waves of matter traveling at relativistic speeds some have been traveling around in the galaxy for 200 million years. I should repeat, most of what we experience on Earth and the ISS are secondary radiation, that is the electrons have been stripped from the protons and some loss of momentum has already occurred. The ability to detect a neutral matter field traveling at the speed of light is virtually impossible (deBroglie hypothesis) therefore it is necessary to slow highly relativistic-particles  in cascades of interactions that steal momentum from the particle.  The preference of shielding for deep space is not the same as for use on ISS or in a fallout shelter . . . . these are two very different problems.

[Shpaget]

1 hour ago, tater said:

they will NOT be colonies. Not ever.

That is such a long time.

Anyway, early bases have little to marginal shielding.

Next generation of facilities, if/when the need for longer stays emerges, gets better protection, why not a bunker.

If/when those bases become lifetime colonies, then we can start thinking of shielding the entire thing. The concept is the same with camping. If you intend to stay more than a few days, you'll be looking at ways to improve your camp, but if it's just for one night, you won't bother with setting up a running water system, flush toilet, or a perimeter fence.

Edited February 16, 2018 by Shpaget

[tater]

5 minutes ago, Shpaget said:

That is such a long time.

The limiting factor on the Moon will be gravity, not radiation. It;s fine as a base, but humans will not raise their kids on the Moon, hence not a colony, and I don't see that changing (centrifuges on the Moon make it a non-starter as a colony).

5 minutes ago, Shpaget said:

Anyway, early bases have little to marginal shielding.

Yeah, they can get it down to occupational levels, since the people in question will spend the vast majority of their lives (and importantly, all of their childhood) in a safer radiation environment (the Earth).

5 minutes ago, Shpaget said:

Next generation of facilities, if/when the need for longer stays emerges, gets better protection, why not a bunker.

Long-term bases, a bunker is fine.

5 minutes ago, Shpaget said:

If/when those bases become lifetime colonies, then we can start thinking of shielding the entire thing. The concept is the same with camping. If you intend to stay more than a few days, you'll be looking at ways to improve your camp, but if it's just for one night, you won't bother with setting up a running water system, flush toilet, or a perimeter fence.

Lifetime colonies not a thing on the Moon, but possibly on Mars, if 0.38g is enough for that (a complete unknown, hence my focus on orbital colonies, since we can make them the known-safe 1g). If so, then the radiation environment needs to be at least as good as the surface of the Earth everywhere inside, IMHO, ideally better than the Earth, since every time people go outside the shielding, they will have higher than Earth doses.

[sevenperforce]

Slight diversion, but are there any thoughts about suitport and airlock alternatives?

It's something that's also viable for nearer-term stuff, like a return to the moon, for example.

Suitports are a nice solution, but they are ungainly, they have poor CoM, and they do not permit transfer of any objects from outside to inside.

Full-vehicle depressurization, as used in the first spacewalks and in the Apollo missions, requires all vehicle occupants to go on EVA together, exposes the interior of the vehicle to hard vacuum, has no protection against dust entry, and uses a lot of consumable resources.

Airlocks, as used on the ISS and proposed for the Altair lunar lander, solve several problems but are heavy, bulky, and require long cycles.

What solutions are available for making EVA a little more...manageable?

[tater]

Airlocks on the Moon or Mars will have to include cleaning facilities for the suits, as the dust is insidious (and dangerous). You are right that the ability to move things in and out is non-trivial, though you could have suitports, AND an air airlock for stuff, perhaps a few of different sizes.

For bases, EVA will be like it is on ISS. On a colony... yeah, it needs to be more "SF" and fast.

[kerbiloid]

2 hours ago, PB666 said:

Fall out shelters are designed to protect from x-rays and gamma radiation, protection is generally heavy metals like lead. The particle type is photons and relatively low velocity alpha particles. Alpha particles are 4 times as heavy as protons.

True GCR are waves of matter traveling at relativistic speeds some have been traveling around in the galaxy for 200 million years. I should repeat, most of what we experience on Earth and the ISS are secondary radiation, that is the electrons have been stripped from the protons and some loss of momentum has already occurred. The ability to detect a neutral matter field traveling at the speed of light is virtually impossible (deBroglie hypothesis) therefore it is necessary to slow highly relativistic-particles  in cascades of interactions that steal momentum from the particle.  The preference of shielding for deep space is not the same as for use on ISS or in a fallout shelter . . . . these are two very different problems.

I meant more or less exponential dependency of protection as a function of thickness, not particular coefficient values themselves.

2 hours ago, tater said:

they will NOT be colonies. Not ever. If people don't live their entire lives there

As if I not agreed.
Even more, while a Martian base/colony/whatever could be a home for several years (just because it's too far and expensive to reach), a lunar habitat probably would be a hostel for several weeks or months.

But it would be nice to treat the lunar personnel as civilians rather than expendables, so they deserve nice and safe cottages to spend those months.

1 hour ago, tater said:

The limiting factor on the Moon will be gravity, not radiation.

And not only on the Moon. On everything solid in Solar System except Venus.

And btw, now about Venusian towns...

1 hour ago, sevenperforce said:

Slight diversion, but are there any thoughts about suitport and airlock alternatives?

Let me mention @p1t1o and my conversation about them.

 

[tater]

Yeah, I'm unsure about Mars for lack of data. I'd like to see SpaceX (since they're all about living on Mars) throw something up on a tether and raise animals for a few generations at 0.38g.

[p1t1o]

2 hours ago, sevenperforce said:

Slight diversion, but are there any thoughts about suitport and airlock alternatives?

It's something that's also viable for nearer-term stuff, like a return to the moon, for example.

Suitports are a nice solution, but they are ungainly, they have poor CoM, and they do not permit transfer of any objects from outside to inside.

Full-vehicle depressurization, as used in the first spacewalks and in the Apollo missions, requires all vehicle occupants to go on EVA together, exposes the interior of the vehicle to hard vacuum, has no protection against dust entry, and uses a lot of consumable resources.

Airlocks, as used on the ISS and proposed for the Altair lunar lander, solve several problems but are heavy, bulky, and require long cycles.

What solutions are available for making EVA a little more...manageable?

 

Thinking about alternatives in a speculative sense, like what might be possible in the far future, for example I mentioned that I find it common in sci-fi for suits to be a nano-tachnological membrane that you "pass through" to apply the suit and the membrane also forms the airlock and is part of the wall.

That is probably a little too sci-fi for much serious discussion but what if we thought closer.

I think its quite well understood that suits will almost certainly develop into a much more form-fitting, if not skin-tight, garment, as vacuum itself isnt actually all-that an agressive environment. Pressure to maintain the body's equilibrium can far more easily be maintained by fabric elasticity than trying to create a human-sized bubble of air. The suits will become far more compact, flexible and resource-efficient, enabling longer spacewalks and a wider range of activities.

So where to after that?

And here's the speculation: since a human only needs a few things to live in vacuum - oxygen, a safe temperature, the retention of fluid and optionally, protection from physical hazards such as radiation, micrometeroids etc.

Since that is the case, is there another solution to surviving other than a suit?

What Im getting at are physical modifications to the body itself.

Now hold your horses, Im not talking about cyborgs here, it could be much more subtle.

• A minor increase in elasticity and tensile strength in the skin.
• An interface, possibly similar to a dialysis machine perhaps, for infusing oxygen into the blood, and removing CO2. Another approach might be a whale-like ability to store vast amounts of oxygen in the body's fluid, like holding ones breath for hours.
• Advanced control over the fluid/gas-permeability of various membranes (lungs, eyes, skin etc.)
• A blubber-like temperature management layer, good for insulation, can be flushed with blood to shed heat. This also ups radiation protection of internals.
• If we were  starting to get ambitious, how about convincing the body to grow kevlar in the skin instead of collagen.
• Potential altering of cellular repair mechanisms to increase resistance to radiation damage. This might also quite literally be a cure for cancer.
• Naturally Im not suggesting going naked, various kinds of protection and utility can be supplemented with equipment in the form of regular clothing (eg: kevlar vest, insulated trousers etc. you get it)

If that were possible - and I dont think they are all that far-fetched if we are talking quite a ways into the future - there would be countless advantages, especially to colonisation.

Edited February 16, 2018 by p1t1o

[sevenperforce]

There's a near-future solution that might actually be workable. I guess you'd call it a FlexLock. Imagine a standard egress hatch, like the one on Dragon 2. Inside the vehicle, place a human-sized doorway as flush as possible against the hatch opening, closed around the perimeter. In normal use, the doorway does not impede or obstruct the hatch, since the doorway only protrudes a few inches from the side of the vehicle (or perhaps slightly more, depending on the interior mold lines).

For use as an airlock, a flexible material (likely a blend of an airtight silicone and something with very high tensile yield strength, like kevlar) is attached to the base of the doorway. For an EVA, the astronaut steps into the doorway, and the material is rolled/zipped up around the perimeter of the doorway. It is stretchy enough that the astronaut's body is still protruding into the cabin area, but the material has sealed him off from the inside. Then the hatch is opened, and he climbs out. The hatch may then be closed. When astronauts need to return, they open the hatch, climb in, using their bulk to push the material back inside the cabin, and seal the hatch.

So it's like a standard airlock, for the most part, but much smaller because the interior hatch is flexible.

[PB666]

20 hours ago, tater said:

Yeah, I'm unsure about Mars for lack of data. I'd like to see SpaceX (since they're all about living on Mars) throw something up on a tether and raise animals for a few generations at 0.38g.

You might want to start with nth generation healthy animals carefully selected from the interior of the Chernobyl Exclusion Zone. DNA damage repair is assumed to have been under selection for greater repair.

[GoSlash27]

On 9/29/2017 at 3:46 PM, sh1pman said:

Well, being a multiplanetary species is more than just "cool". It can save us from some cataclysmic event. Or overpopulation. Doesn't always have to be economically feasible.

sh1pman,

 Unfortunately, that only works if the colonies are 100% self- sufficient. This is a far more daunting task than the job of setting up colonies. If the colonies are dependent on Earth for any supplies whatsoever, they are still doomed if a cataclysmic event should befall the Earth.
 As for the problems of overpopulation, space has never been the answer to that problem. There will always be plenty of living space. The problem is food, which requires air, arable land, water, livestock, and a complete biosphere. All lacking everywhere except on Earth.

Best,
-Slashy

[Bill Phil]

6 minutes ago, GoSlash27 said:

sh1pman,

 Unfortunately, that only works if the colonies are 100% self- sufficient. This is a far more daunting task than the job of setting up colonies. If the colonies are dependent on Earth for any supplies whatsoever, they are still doomed if a cataclysmic event should befall the Earth.
 As for the problems of overpopulation, space has never been the answer to that problem. There will always be plenty of living space. The problem is food, which requires air, arable land, water, livestock, and a complete biosphere. All lacking everywhere except on Earth.

Best,
-Slashy

Overpopulation occurs when the population exceeds the carrying capacity. We're not at that point, but it has little to do with living space. It refers to food, air, arable land, water, livestock, and the biosphere.

[tater]

World pop is expected to flatten out in the near future, actually.

[sevenperforce]

10 hours ago, tater said:

World pop is expected to flatten out in the near future, actually.

 Because lots of people will die.

[Bill Phil]

40 minutes ago, sevenperforce said:

 Because lots of people will die.

No. Birth rates ate expected to decline and death rates will slightly rise (at least in the US, mostly due to the age of baby boomers).

[tater]

Yeah, worldwide, poverty markers are all down, and birthrates drop with increased economic security.

[kerbiloid]

Tell about the markers to the countries where 50% of population are of the age below 18 and are going to marry and have children.

[Green Baron]

12 hours ago, tater said:

World pop is expected to flatten out in the near future, actually.

No. It is by no means clear and get as well grow to 11billions or more.

[tater]

http://www.prb.org/publications/Datasheets/2012/world-population-data-sheet/fact-sheet-world-population.aspx

6 hours ago, Green Baron said:

No. It is by no means clear and get as well grow to 11billions or more.

11, then start to flatten out. That's the middle of the road estimate, anyway. Not exponential growth indefinitely.

8 hours ago, kerbiloid said:

Tell about the markers to the countries where 50% of population are of the age below 18 and are going to marry and have children.

It's still better than it used to be. At every moment in human history, (minus small wobbles up and down), you are at the safest period in history to be a human.

https://ourworldindata.org/extreme-poverty

There is still much to be done, but the trend lines are in the right direction.

[tater]

On topic: if we made the world more Blade Runner like (a dystopia), then this would provide a rationale for the "off world colonies" that some here desire

 

[PB666]

1 hour ago, tater said:

http://www.prb.org/publications/Datasheets/2012/world-population-data-sheet/fact-sheet-world-population.aspx

11, then start to flatten out. That's the middle of the road estimate, anyway. Not exponential growth indefinitely.

It's still better than it used to be. At every moment in human history, (minus small wobbles up and down), you are at the safest period in history to be a human.

https://ourworldindata.org/extreme-poverty

There is still much to be done, but the trend lines are in the right direction.

There is an assumption about sustainability in the data. In some areas of the World, e.g. Siberia/Canada sustainability will improve. In most areas of the world sustainability will decline.
The current models predict that many areas will decline in agricultural output in a process that will increase unless there are national and continental water plans.
IMO, 11 billion humans at current energy utilization in non-poverty states is not sustainable and will result in population collapse.

 

[Kerbal7]

On 2/15/2018 at 3:37 PM, tater said:

It's manageable for an expedition. NASA DRMs have it slightly exceeding lifetime allowed workplace radiation exposure as set by OSHA, so any Mars astronauts for NASA would not fly again. Mitigation schemes are also possible (the DRMs have little/no shielding). The Lockheed Martin Mars Basecamp idea has the crew sleeping quarters surrounded by the propellant tanks, so that substantially reduces radiation exposure in flight to and from Mars.

For both the Moon, and Mars, regolith could be used as shielding. Have robot excavators bury the hab areas ahead of crew arrival, for example. They might bury just the sleep quarters to start (a smaller, hardshell lander), then the crew inflates a larger, connected common area hab, and works on shielding it themselves (for the year stay variety of mission).

 

Just finished the first season of National Geographic's Mars. They had the explorers find a lava tube to place their habitats in. This kept them safer from the lethal radiation on the surface. Makes me wonder who would want to really live on Mars. Visit, cool. Live, not so much.  

[tater]

44 minutes ago, Kerbal7 said:

Just finished the first season of National Geographic's Mars. They had the explorers find a lava tube to place their habitats in. This kept them safer from the lethal radiation on the surface. Makes me wonder who would want to really live on Mars. Visit, cool. Live, not so much.  

Yeah, I cannot see a rationale for people wanting to move to Mars forever for any reasonable % of the population, seems nuts to me. I love hiking in areas even more of a desert than my own yard---but I prefer to come home, lol.

I watched much of that Nat Geo Mars show, and had trouble watching it for many reasons.

[tater]

Earth EDL is actually easier than Mars, there's far more atmosphere to dump velocity with.

5 hours ago, Kerbal7 said:

The whole city on Mars thing is like hearing a crazy uncle talk though.

You'll get no disagreement from me regarding cities on Mars. I can't see any way they make sense. They need stuff from Earth, and they'll have no money to buy that stuff with, or anything to sell to get money.