[HN Gopher] Moon's top layer has enough oxygen to sustain 8B peo...
___________________________________________________________________
Moon's top layer has enough oxygen to sustain 8B people for 100k
years
Author : samizdis
Score : 174 points
Date : 2021-11-11 10:56 UTC (12 hours ago)
(HTM) web link (theconversation.com)
(TXT) w3m dump (theconversation.com)
| yc-kraln wrote:
| The moon has no magentic field. There is no protection from
| cosmic rays, not enough gravity to keep an atmosphere, not for
| nothing that there is currently no known life there.
|
| Life needs more than oxygen. Why do we keep positioning the Moon
| as some sort of life boat for when we muck up Earth past the
| point of survivability?
| WarOnPrivacy wrote:
| I am grateful I still get to seen an unaltered moon.
| scott_joe wrote:
| I realize it's an issue for my grandchildren's great
| grandchildren, but does anyone wonder if future generations will
| look up at the moon and wonder what their ancestors saw because
| it's been defaced (moon pun) by mining?
| Reason077 wrote:
| It would also make a great advertising billboard! Imagine
| looking up at the night sky from anywhere on earth and seeing a
| giant, glowing Apple or McDonald's logo carved into the moon's
| surface!
| selimthegrim wrote:
| Way to trigger the Moon Man memories.
| fiftyfifty wrote:
| You ever wonder what Manhattan used to look like before New
| York City was built or San Francisco Bay? We've leveled
| mountains mining coal and covered deserts and seas with oil
| rigs. Unfortunately this is not a new problem for humans.
| doodlebugging wrote:
| I hope I never see the day when a casual glance at a full moon
| reveals a large dust cloud from active moon mining obscuring part
| of the details that I've become familiar with over my lifetime.
|
| I'm not sure the moon needs those type of scars.
|
| Maybe they'll find a way to use an N99 filter dome over their
| operations.
|
| The progress of man seems so naturally tuned towards destructive
| outcomes. We bounce from one fucked up scenario to another, each
| one an attempt to put a band-aid on a gaping wound left by our
| failure to consider how our technological progress seems to leave
| us with ever more urgent issues to address to insure our own
| survival and that of our descendants. Maybe we're the virus that
| is learning how to defeat the planet's immune system and
| ultimately kill it.
| fennecfoxen wrote:
| Dust clouds won't happen on the moon due to lack of an
| atmosphere. You can get a localized dust plume, but not fine
| particles drifting away for thousands of miles in the manner
| of, say, the California fires.
| doodlebugging wrote:
| Thanks for pointing this out.
|
| I actually considered this with the understanding that any
| dust clouds would be localized and persistent due to the
| lower gravity on the moon. The finest fraction of moon dust
| will remain suspended longer than here on earth and the
| absence of wind will localize the effects. This suspended
| dust will over time, blur our view from earth of the areas
| being actively exploited for minerals, oxygen, etc.
|
| I don't see the practicality of conducting mining operations
| under a dome to localize and control dust so the machinery
| being employed will be outside any containment and when you
| do this on a massive scale to potentially support
| interplanetary travel you will raise a cloud of dust that
| will take a long time to settle.
|
| I am opposed to this. Since we are two different people with
| different life's experiences, you don't have to be.
|
| Thanks for adding to the discussion.
| s1artibartfast wrote:
| I think you are making a lot of assumptions about the
| visibility of any possible dust cloud.
|
| First, you have to take into account size. The smallest
| feature on the moon that can be seen with the naked eye is
| ~ 300km in diameter. IF aesthetics are your main concerns,
| plumes smaller than this should be no problem.
|
| 2nd, I don't agree that dust will remain suspended longer.
| Dust on earth is suspended in the atmosphere, which the
| moon lacks. On the moon, dust follows a parabolic
| trajectory, like a thrown rock on earth.
|
| Last, lunar dust is the same color as the lunar surface.
| like a white cloud on a white background, it would be
| extremely difficult to differentiate.
|
| I personally think a dust cloud on the moon would be cool,
| but this is beside the point.
| doodlebugging wrote:
| I understand your viewpoint. I disagree that dust from
| mining on the moon would be cool and that the dust would
| be mostly invisible. Once mining begins, if the
| processing is successful and their objectives are met,
| the operations will most likely scale up and that is when
| the ability to spot these changes from earth will become
| easier.
|
| Thanks for contributing to this discussion.
| s1artibartfast wrote:
| to be clear, We are already talking about a hypothetical
| scenario where there are 8 billion people living on the
| moon, and your concern is that the mining could further
| scale up beyond this?
|
| If you are not interested in engaging further on the
| technical question of if dust would be visible, or the
| relative value of aesthetics vs utility, I guess there
| isn't anything to discuss at all.
| fennecfoxen wrote:
| No, no, there is no suspended dust!!!
|
| Suspension requires an atmosphere! All dust particles on
| Earth experience a 9.8 m/s2 acceleration towards the
| surface of the Earth, but other forces from the moving
| gases in Earth's atmosphere around them can easily overcome
| that for a small particle.
|
| All dust particles on the Moon will experience a 1.62 m/s2
| acceleration towards the surface of the Moon -- which is
| lower -- but there are no gases to stop them. They are on a
| ballistic trajectory from wherever they they were launched.
| They will impact the surface of the Moon in fairly short
| order, unless you launch the dust at orbital or escape
| velocity (upwards of 2 km/s in both cases).
| doodlebugging wrote:
| Even if all dust particles settle in minutes due to lack
| of an atmosphere, the fact that they will need to
| continue mining operations indefinitely to sustain their
| existence means that an observer on earth will likely be
| able to determine where they are by the permanent changes
| they make to the moon surface. It only requires one to
| monitor the moon over an extended time period. The scale
| of the operation will define how long that time period
| will be.
|
| A larger scale operation that might provide oxygen or
| fuel for boosters traveling away from earth might need to
| operate full-time for extended periods so that mining
| operations will be creating a cloud of dust constantly
| and though it may settle slowly, it will probably be
| detectable.
|
| Since many of the moon mining plans involve using it as a
| base for operations away from earth it seems unlikely
| that these operations would be one and done. I think that
| once you prove that you can satisfy that need for fuel or
| air to breathe in your operations and processing that it
| will only ramp up with time as new uses will be
| discovered.
|
| I could be wrong. It would not be the first time nor is
| it likely to be the last.
| scoopertrooper wrote:
| The surface of the moon is just a bunch of pockmarks left over
| from a millennia of collisions with other space objects. Is
| that really something worthy of preservation?
| colanderman wrote:
| The moon and its near-side features are the single visual
| landmark shared by _literally all of humanity which has ever
| existed_. Many would call it sacred. We preserve all sorts of
| rocks on Earth which are similarly majestic
| /significant/sacred, despite being formed by random
| geological processes. Why not the visual facade of the moon?
| doodlebugging wrote:
| This is the question we have to ask ourselves as a people.
|
| What value do we place on things that we have all enjoyed
| and marveled at? Which one or which group of us gets to
| speak for all of us?
| scoopertrooper wrote:
| The lunar surface is constantly changing due to collisions.
| So, what are we preserving exactly?
|
| https://www.space.com/34372-new-moon-craters-appearing-
| faste...
| colanderman wrote:
| Trees constantly change. Why preserve a forest?
|
| (Not to mention, OP was talking about large obscuring
| dust clouds. Not pockmarks.)
| scoopertrooper wrote:
| Nobody is talking about chopping down the moon.
|
| I think OP doesn't realise how big the moon is. Those
| asteroid impacts kick up massive plumes of smoke, but we
| don't really notice it because the Moon is pretty freakin
| big.
| doodlebugging wrote:
| OP here. Actually not OP, just top of this thread.
|
| I'm actually a geophysicist. I do have a pretty good idea
| not only of how large the moon is, but of where it is in
| relation to earth, it's age, common rock types found
| there, origin theories, its effect on earth, its cultural
| usage down through time, etc.
|
| In my own work I have used knowledge of tidal effects to
| help me correct seismic data to optimize subsurface
| resolution so that companies could determine whether
| there was a resource there that could be economically
| exploited.
|
| I appreciate you taking the time to read my original post
| and to comment. This is exactly the sort of discussion I
| figured it would generate.
| doodlebugging wrote:
| I think that is the question that we have to ask ourselves.
| Thanks for getting the ball rolling.
| [deleted]
| colanderman wrote:
| I don't know why people are having such a visceral negative
| reaction to your post. The near face of the Moon has been since
| the dawn of humanity the single natural formation visible to
| and enjoyed by every (sighted) human who has ever existed.
| Preserving it for future humans seems not only natural, but
| imperative.
| politician wrote:
| Absolutely! Let's make sure to have enough machinery on the
| Moon to repair impacts from meteorites, too!
| colanderman wrote:
| Your needless sarcasm belies the fact that you either
| missed or are ignoring that the OP's concern was about
| large persistent dust clouds obscuring major features. Not
| pockmarks.
|
| You've been here ten years, so I would think you're
| familiar with HN guidelines [1], but please remember:
|
| > Please don't sneer, including at the rest of the
| community.
|
| > Please respond to the strongest plausible interpretation
| of what someone says, not a weaker one that's easier to
| criticize.
|
| [1] https://news.ycombinator.com/newsguidelines.html
| politician wrote:
| There's a group of folks here that believe we should
| eliminate all exploration for the sake of ambiguous and
| vague goals of "preservation". They pop up in every
| discussion of the future, demanding explanations for why
| people of whom they have no affiliation should use
| resources of which they have no ownership for purposes
| over which they have no reasonable control.
|
| Consider directing your volunteer HN moderation at that
| absurdity.
| wombatpm wrote:
| Fine, put everything on the farside.
| colanderman wrote:
| Sounds good to me.
| roamerz wrote:
| Sorry pal we not a virus we are life. When you see that dust
| cloud on the moon marvel at the technology required to pull
| that off rather than the visual indicators that you find
| disturbing. I love going to Death Valley and seeing the
| remnants of old gold mines and other activities of past. They
| are scars to some maybe but not to all.
| doodlebugging wrote:
| OP here (actually the top of this thread, not OP on the
| post). Thanks for commenting pal.
|
| I've had lots of time to marvel at technology in my nearly 40
| year oil and gas career. A lot of the work that I did when I
| started in the exploration end of that industry has now been
| used, even decades later, to drive exploitation in areas that
| I came to know and appreciate for their raw beauty and
| isolation. The rock cycle teaches us geoscientists (I'm a
| geophysicist) that time changes everything and not even the
| rocks are forever.
|
| In the grand scheme of things looking down through time it
| appears that a case could be made for humans being only the
| latest one of a series of afflictions that earth has endured
| in the past. No doubt earth is resilient enough to survive
| and establish a new equilibrium should we manage to deplete
| enough resources here that we can no longer survive as a
| species, and like rats escaping a flood, hop on any
| interstellar flotsam available in a bid to save ourselves
| from our own technologically-induced suicide.
| colanderman wrote:
| I read somewhere that during the Industrial Age, there were
| people who loved the sight of a smog-choked city as an
| indicator of progress.
|
| I for one am glad that sentiment no longer prevails.
| globular-toast wrote:
| There are people who see skyscrapers and car-clogged
| streets as a sign of progress today.
| roamerz wrote:
| Got me on that one though I was outside yesterday morning
| and the smell of wood smoke was very nice. That's from a
| guy who has lived through many recent and past smoke filled
| summers that have been helped along (fueled) by those who
| wanted to stop progress by halting responsible logging.
| Their tool? The Spotted Owl. Sorry to see how well that is
| working out for them.
| s1artibartfast wrote:
| You seem to assume any of this would be visible from earth. Why
| is that?
| Someone wrote:
| The moon's area is about 38 million km2, so that would be 'only'
| about 200 persons/km2.
|
| That's less then I would have guessed (cities can have tens of
| thousands of people/km2), but still way over the current world
| average (excluding water areas) of about 15/km2.
| baybal2 wrote:
| Oxygen is one of the most omnipresent elements. Getting nitrogen,
| and hydrogen is a much bigger issue.
| Sunspark wrote:
| The future: The moon as prison planet. At the top of the gravity
| well, only the most hardened convicts arrive to serve out their
| sentences in this new Oz. Put to hard labour mining resources,
| ceaselessly administered and regulated by the state automatons.
| Almost all sentences to the moon are one-way.
| amildie wrote:
| Unless they're mining straight up bitcoin there is absolutely
| no way that maintaining a prison facility on the moon would be
| profitable for the state.
| Sunspark wrote:
| There's a lot of valuable Helium-3 on the lunar surface. It's
| very impractical today to contemplate using it, but if
| materials science ever advanced enough that we could
| construct a space elevator, it might be feasible to do
| exactly that because 1 ton of Helium-3 can apparently
| generate 1.5x the energy of a Tsar Bomba.
| akomtu wrote:
| You might be interested to know that in occultism, Moon is
| sometimes referred to as "the eighth sphere" for reasons you've
| just described.
| GordonS wrote:
| I'm reading Peter F. Hamilton's _Salvation_ just now, and
| Zagreus is used as a kind of penal colony, with global
| corporations having their own clandestine security forces that
| rendition anyone that opposes them.
| xibo9 wrote:
| "The Moon is a Harsh Mistress" by Heinlein?
| [deleted]
| gcanyon wrote:
| Pretty sure it takes less energy to split CO2 than it does to
| split aluminum oxide. So recycling after the first extraction
| would make more sense.
| lmilcin wrote:
| Sounds like a plot of Artemis by Andy Weir.
|
| They are literally scraping top layer and smelting it for
| aluminium with oxygen as a side product.
| tokai wrote:
| Its not like its a new concept. There is literally thousands of
| articles, from the last millennia, about oxygen mining and
| production on the moon.
|
| https://scholar.google.com/scholar?q=mining+moon+oxygen&hl=d...
| [deleted]
| fghorow wrote:
| Geophysicist here.
|
| "Sillicates." (Emphasis on the "ates".)
|
| Oxygen is an integral part of most rock-forming minerals.
|
| 'Nuff said.
| baby-yoda wrote:
| somewhat tangential - as a kid I loved science fiction and
| stories about the next great frontier. it was fascinating, the
| possibility of limitless exploration and new problems to solve.
|
| perhaps my perspective has been skewed over time (or this concept
| was lost on my naivety at the time) but now it feels like
| interstellar colonization is more about an escape hatch for the
| inevitable end of civilization on earth. we'll destroy
| (intentionally or not) what we have here, set up shop somewhere
| else and start the process all over again?
| fennecfoxen wrote:
| Unlikely. If we have the technology to render dead worlds
| habitable we have the technology to render even a post-
| apocalyptic Earth habitable: a fraction of the difficulty, and
| you save a lot on rockets.
| kogus wrote:
| Better watch out for Lord Helmet and Spaceball One... (sorry, I
| couldn't help myself)
| bondolo wrote:
| Why would you want to live there? I can imagine the moon being a
| place for mining, industrial operations and as a staging base for
| outer system missions. But a place to live? No, sorry, if a place
| fails the test that Antarctica is more hospitable and commodious
| I can't imagine people living there without a specific purpose.
| And, just like Antarctica, the high cost of keeping people alive
| there is going to always (OK for at least the next couple of
| thousand years) limit the practical population.
| t0mas88 wrote:
| OK, but they're talking about all the oxygen molecules that are
| in metals. And then digging 10 meters deep for the whole moon,
| assuming 100% can be extracted and get to the clickbaity number
| in the title.
|
| Does anyone know how this compares to earth? And what amount of
| energy is needed to practically make some human usable oxygen?
| jacquesm wrote:
| > Does anyone know how this compares to earth?
|
| The Earth doesn't need this because it has a breathable
| atmosphere, but you can just look at the oceans and ballpark
| figure that to about 8/10ths of their mass (the oceans, not the
| planet).
|
| Mars would be a better comparison to the moon.
| dotancohen wrote:
| > Does anyone know how this compares to earth?
|
| Oxygen is the single most common element in the Earths crust.
| roenxi wrote:
| It is an interesting thought. Note that sand - often silicon
| dioxide - contains a lot of oxygen.
| Cthulhu_ wrote:
| And water - composing 71% of the earth - is two hydrogen, one
| oxygen atom. That's just the atoms of water itself, on top of
| that, a lot of oxygen is dissolved in the water itself.
|
| tl;dr the earth has plenty of oxygen, it's not really a
| problem. Other gases are though.
| zokier wrote:
| > And water - composing 71% of the earth
|
| Far less actually. From Wikipedia:
|
| > The total mass of Earth's hydrosphere is about 1.4 x
| 10^18 tonnes, which is about 0.023% of Earth's total mass
| hutzlibu wrote:
| He was talking about surface. 71% of the earth is covered
| by water.
| mcdonje wrote:
| Great article. "Artemis" by Andy Weir revolves around a moon base
| that makes its own oxygen this way. Fun read.
| atonse wrote:
| But how about the other important element in our atmosphere that
| we breathe: nitrogen? Among others.
|
| Cuz if it's just pure oxygen I'm pretty sure that's not safe.
| kadoban wrote:
| You can breathe pure oxygen without issue if it is at lower
| pressure. I don't know of any other gasses that are actually
| needed.
| hutzlibu wrote:
| Also the nitrogen would not get used up by humans.
|
| Only for growing plants, we would have to bring some or
| extract it somehow?
| kadoban wrote:
| Yeah I guess we'd have to bring it as fertilizer.
|
| I tried to look up if nitrogen exists on the Moon, seems
| like it basically does not. I didn't realize how rare
| carbon is there either. We'd need to bring a _lot_ of
| things it seems.
| G3rn0ti wrote:
| Oxygen is actually pretty inert i.e. non-reactive and therefore
| safe to breathe in pure form (as aquatic divers do, I believe).
| The reason for that is most of atmospheric oxygen is composed
| of "triplet oxygen" referring to its outer shell electron
| configuration being rather stable. For reactions to occur
| triplet oxygen first needs to be activated and converted into
| "singlet oxygen" being rather aggressive chemically. This is a
| "kinetic" barrier that renders gaseous oxygen pretty harmless.
| This is also the reason why organic matter on earth does not
| spontaneously catch fire although CO2 + H2O is always
| energetically more favorable than every CXHXOX composition.
| xwdv wrote:
| Even if we can sustain many individuals on the Moon it would
| likely be permanent for them as the long term physiology of such
| humans would be affected by the low gravity there.
| temptemptemp111 wrote:
| Hilarious that you people are so brainwashed. Not enough drag to
| influence the orbit that doesn't show even 1% of the "dark side"
| ever... But enough to sustain life... Funny how these
| "discoveries" (falsifications) never need to be on the orbit math
| for satellites ISS et all... Fake!
| acd wrote:
| So you do concentrated solar sintering of the moon rocks and
| extract the oxygen?
| mkl wrote:
| This is assuming the oxygen is used once then somehow eliminated.
| In practice that exhaled oxygen, as CO2, would probably be
| absorbed by plants, e.g. food crops, and recycled into O2.
|
| Also, smelting aluminium takes a _lot_ of power. The Tiwai Point
| Aluminium Smelter [1] uses 13% of New Zealand 's electricity to
| separate the aluminium and oxygen.
|
| [1] https://en.wikipedia.org/wiki/Tiwai_Point_Aluminium_Smelter
| anthony_r wrote:
| Yeah, that's what I don't get: if you're going to invest effort
| and energy into reversing the oxidation of some element, why
| not choose carbon and decompose CO2? It will require non
| trivial amounts of energy either way.
| politician wrote:
| It's better to get a metal for the effort.
| mkl wrote:
| There is very little CO2 on the moon, so that's not really an
| option.
| rendall wrote:
| Humans, livestock and industry will introduce it.
| Joeri wrote:
| On the plus side for power, on the moon solar panels can
| operate at maximum efficiency all day every day. Build a
| network that spans the circumference and you get a reliable
| power grid.
| imglorp wrote:
| Another plus, you don't need electricity to make a solar
| reflective furnace. The lower gravity would be helpful
| building a field of reflectors or a large arecebo-like dish
| in a crater.
| Retric wrote:
| The moon is a terrible place for solar power. Solar panel
| efficiency drops by about 0.5 percent per degree Celsius over
| 25C, which is a real issue when the moons daytime temperature
| hits 110C (230f) Aka past the boiling point of water.
|
| The day night cycle is almost a month long which means you
| need extreme energy storage, but daytime temperatures go from
| colder than the arctic winter to past the boiling point of
| water. The poles don't get as hot, but they also get months
| long night due to the moons axial tilt.
| jerf wrote:
| Photoelectric power isn't the only form of solar power.
|
| But no matter how you slice it, that two weeks of darkness
| is a problem. You're going to need nuclear power up there.
| Fortunately, most of the objections to it on Earth don't
| apply up there. Space is _already_ a radioactive hell scape
| in general, there 's nothing alive to kill, there's no
| (currently-known) mechanisms for waste to propagate
| anywhere you didn't originally put it, etc. etc. We know we
| can build fission reactors small enough to put out
| reasonable amounts of power and fit into a payload of a
| rocket, since we have vessels powered by them already.
| Retric wrote:
| Yes RTG's are by far more common but there have actually
| been real nuclear reactors in space. That said cooling
| during the day is a real though solvable problem.
| credit_guy wrote:
| > the moons daytime temperature hits 110C
|
| The notion of temperature is quite weird on the Moon.
| There's no air over there, and temperature does not make
| sense in a vacuum. Or rather, there's some type of
| temperature, but it does not affect the solar panels,
| simply because the solar panels of countless satellites
| work just fine.
|
| One could say that the 110C refers to the temperature of
| the regolith. But that's only if the regolith is directly
| exposed to the sun, which obviously will not be the case
| for the regolith underneath the solar panels. And even if
| it were the case, you can make the supports of the solar
| panels to be thermally insulating, and again, since there's
| no air, there won't be any way for the heat to travel from
| the regolith to the panels.
| Retric wrote:
| It's not quite that simple as over 2 weeks of sunlight
| heat conducts a fair distance. Also, the regolith emits
| IR radiation so a shadow wouldn't be nearly as cool in
| the daytime.
|
| That said, there are options such as coating the surface
| in a reflective coating, or using a large thermal mass to
| cool in the day and warm at night. Really the point isn't
| it's impossible to use solar on the moon, just
| significantly more difficult than on a satellite.
| scoopertrooper wrote:
| Sounds like thermal solar might be a better for the moon.
|
| https://en.wikipedia.org/wiki/Solar_thermal_energy#High-
| temp...
| Retric wrote:
| Solar thermal is limited by Carnot efficiency, you want
| to move heat from hot to cold areas.
| geoduck14 wrote:
| >Solar panel efficiency drops by about 0.5 percent per
| degree Celsius over 25C, which is a real issue when the
| moons daytime temperature hits 110C (230f) Aka past the
| boiling point of water.
|
| Don't they already handle these extremes in satellite solar
| panels?
| Retric wrote:
| The back of solar panels are to the void of space. On the
| moon it's to the moon's surface which might initially be
| cold but would warm over time.
| jjk166 wrote:
| Just align your radiators vertically so their flat
| surfaces point towards the horizon (ie the void of
| space). Actually you'd want to slightly angle them such
| that they are still pointing towards empty space but not
| at the next radiator over, but still you get the idea.
| themaninthedark wrote:
| It depends on how they handle them, oversize the solar
| panes to ensure that you never drop below your minimum
| operation current requirements?
|
| That is a very good question, because larger panels would
| mean more mass and cost more.
|
| So careful balancing of the factors? or a different panel
| formula?
| willis936 wrote:
| There is also an abundance of He3 in the upper crust of the
| moon. You could centrifuge that out and use it to fuel a
| D-He3 fusion reactor (assuming you could make such a reactor
| work terrestrially, ship millions of tons, and assemble such
| a facility on the moon).
|
| D-He3 is the lowest temperature aneutronic fusion reaction.
| Not all fast neutron hardening problems go away because a
| small cross section of reactions will be D-D even at the
| higher temperature (and potentially short bursts of higher
| fast neutron flux if temperature control is inadequate and
| low). However, most of the energy comes out as fast charged
| particles, which is open to direct conversion. Ditching the
| steam cycle is a big deal in terms of plant size and weight.
| CamelCaseName wrote:
| I was curious, so I looked it up.
|
| Circumference of the moon: 10,921km
|
| Longest power transmission line: 2,543km (Belo Monte-Rio de
| Janeiro transmission line, Brazil)
|
| So it sounds quite feasible actually
| Reason077 wrote:
| > _" So it sounds quite feasible actually"_
|
| But even more so near the poles, where there's no need to
| build transmission lines around the entire circumference to
| access constant sunlight. Prime real estate for moonbases!
| simonh wrote:
| The tradeoff there is that due to the angle of incidence,
| for a given area of the moon's surface you get a lot less
| energy. That means angling your panels vertically and
| spreading them out very widely to capture the same energy
| as you would at the equator. Or build a huge solar panel
| wall as high as you can that rotates.
| BiteCode_dev wrote:
| There is no wind and weak gravity, so you can build high.
| rootsudo wrote:
| I enjoy this conversation - all the limitations we're
| used to on earth - no longer apply. It's pretty amusing.
|
| What if the moon was just a mining and energy "moon" how
| amusing would that be.
| dustintrex wrote:
| Unfortunately there are a whole host of new limitations,
| some obvious (no atmosphere) and some less so (moon dust
| is super abrasive because there's no wind or water to
| file it down).
| dylan604 wrote:
| Think of the extra-global supply chain disruptions that
| are possible though. We're talking easier to disrupt than
| a ship going sideways through a canal.
| kreeben wrote:
| Stop tickling my imagination like that. It's not fair to
| a person who's almost 50.
| rbanffy wrote:
| > for a given area of the moon's surface you get a lot
| less energy
|
| Without atmosphere, you just point the panel to the sun
| and you'll get 100% power again regardless of how low the
| Sun is over the horizon.
| hutzlibu wrote:
| But when you have to move your panels, it suddenly
| involves lots of moving parts, that break down and
| require maintainance, etc.
|
| Because ... microasteroids and co.
|
| The missing atmosphere that gives you more light also do
| not protect you against countless small projectiles.
|
| But when space is not a problem: I would just use solar
| foil. Not as efficient per square meter, but can cover
| much more area with a given volume and weight freight
| restraint.
| rbanffy wrote:
| > do not protect you against countless small projectiles.
|
| They'll hit you all the same regardless of your
| movements. A very simple mechanical system that does a
| full rotation every 28 days would suffice.
|
| If you don't need to import the solar foil from Earth, it
| becomes a much better alternative. Low maintenance means
| nobody needs to visit the surface to fix stuff.
| PaulHoule wrote:
| At some point the solar panels start obscuring each other
| or you have to go vertical.
| rbanffy wrote:
| Only if they are very close to one another. At that
| point, you would rely on a different solar plant on the
| ring.
| PaulHoule wrote:
| Then you have to run more wires.
|
| Contrast that the asteroid materials/free space situation
| where the solar collector is made from a polymer film
| coated with thin films of metals and/or semiconductors to
| either reflect and concentrate or convert energy.
|
| The title of that article suggests that oxygen is
| limiting but really you need 4 parts N2, Helium, SF6, or
| some other inert for one part of O2 if you don't want
| everything to burn up. Those large airspaces in the
| O'Neill colonies are unrealistic for that reason.
|
| H2O is limiting in terrestrial ecosystems and that is
| true in the rest of the universe. Part of the resolution
| of the Fermi 'paradox' is that most of the life in the
| universe is outside the frost line where a significant
| part of most bodies is water. Liquid water is generic in
| outer solar system bodies and probably some interstellar
| bodies where it takes tremendous luck for dry inner solar
| system bodies to have a thin sheen on the surface like we
| do.
|
| I can picture a 'Galileo' on a slightly less cooked Io or
| more cooked Europa getting hassled by the church about
| the significance of oxygen in the Earth's atmosphere.
| 'Don't you know life would be impossible without high
| levels of radiation?'
| simonh wrote:
| We're talking about arrays big enough to circle the moon,
| that's massive scale. Putting those on the poles will
| dramatically reduce the radiation you can intercept for a
| given area, and there's a lot less space at the poles
| than round the equator, because sphere. For smaller
| arrays the poles make perfect sense.
| rbanffy wrote:
| Unless the panels you describe can't rotate and always
| face up, there is no change in the amount of sunlight you
| get per area between the pole or the equator.
| simonh wrote:
| Except, as has already been pointed out, you have to
| space out angled panels much further apart longitudinally
| near the poles otherwise they block each other. We're
| going round in circles on this.
|
| Consider a relatively modest 1km square patch of such a
| massive array. At the equator this patch will consist of
| panels laid out flat horizontally relative to the
| 'ground', with a 10m patch spaced every 10m (no gap). At
| 80 degrees latitude this patch will consist of panels
| angled up at 80 degrees in longitudinal strips. Let's say
| each panel is a square 10m x 10m. If the next strip
| towards the equator is placed 10m away from the foot of
| the strip 'behind' it, almost all of the strip behind
| will be obscured in it's shadow. In fact the strips would
| need to be spaced about every 60m instead of every 10m.
| That's 1/7th the density. Instead of 1 sq km of panel
| area you'd only have 0.14 sq km of panels.
| rbanffy wrote:
| If we circle the Moon, even near the poles, we are
| talking about many square kilometers of solar panels.
| Unless energy consumption by our lunar civilization is
| _totally insane_ , I wouldn't mind some of the panels not
| generating power in some alignments (half of them
| wouldn't generate any power half of the time anyway).
| [deleted]
| hoseja wrote:
| I imagine installing superconducting grid might be
| feasible, too.
| chii wrote:
| like a mathematician, anything that is theoretically
| proven is considered trivial.
| mkl wrote:
| If you're transmitting around the night side you could
| use the extreme cold to help with that. Transmitting when
| the sun is shining on your grid is another story.
| politician wrote:
| You could build some pretty impressive Stirling engines
| with the heat difference between the light and dark
| sides.
| dylan604 wrote:
| make them mobile rovers that maintain their position on
| the terminator to keep a night/day split.
| cvak wrote:
| Just like Cathedrals in Absolution Gap.
| Reason077 wrote:
| PRO TIP: locate your moon-base near the lunar poles where
| this is significantly easier/cheaper!
| Retric wrote:
| The pools get months long night just line on earth. You
| would need to build a mega structure with rotating panels
| or have serious batteries.
| Reason077 wrote:
| The moon only has a 1.5 degree axis of tilt, so unlike on
| earth (23.5 degree tilt!) the seasons aren't super
| pronounced.
|
| It's true that there are still short periods of darkness
| even at the poles, but they're not months long like on
| Earth.
|
| Further, you could still access 24 hour sunlight by
| building a transmission grid with multiple solar panels,
| but the length of the transmission lines required would
| be _much_ shorter near the poles.
| wcoenen wrote:
| From the article:
|
| > _You might be familiar with this if you know about
| electrolysis. On Earth this process is commonly used in
| manufacturing, such as to produce aluminium. An electrical
| current is passed through a liquid form of aluminium oxide
| (commonly called alumina) via electrodes, to separate the
| aluminium from the oxygen. In this case, the oxygen is produced
| as a byproduct._
|
| This is currently not the industrial reality.
|
| Aluminum is typically produced via the Hall-Heroult process which
| involves a carbon source and emits CO2. (Alternative processes
| which only emit oxygen are possible, but presumably those are
| more expensive.)
|
| https://en.wikipedia.org/wiki/Hall%E2%80%93H%C3%A9roult_proc...
| TheOtherHobbes wrote:
| One of the first and most immediate challenges for any Moon or
| Mars base is an excess of CO2.
|
| It won't cause lunar warming. But it will still be a problem
| and require significant energy and other resources.
|
| It's likely that it will either be impossible or prohibitively
| expensive to keep CO2 levels at normal Earth standards.
|
| See also: the ISS which operates with much higher atmospheric
| CO2 levels (up to 5000ppm) than would be considered healthy on
| earth (up to 1000ppm).
| Robotbeat wrote:
| It's take much less energy to maintain Earthlike CO2 levels
| in a habitat than it already does to make the oxygen that
| astronauts consume.
| neartheplain wrote:
| The Soviets solved this problem in their closed ecosystem
| experiments of the 1970s using 8 m^2 of algae per person:
|
| https://en.wikipedia.org/wiki/BIOS-3
| coryfklein wrote:
| Forgive my ignorance, but why is excess CO2 such a challenge?
| Isn't it extremely easy to simply vent it into space/the
| nearly-empty moon atmosphere?
| jjk166 wrote:
| Carbon isn't plentiful on the moon's surface so you want to
| conserve it for long duration missions/permanent habitats.
| Unfortunately storing it as CO2 in the air isn't great for
| human health.
| ajuc wrote:
| You need food production anyway for a sustainable moon
| base. After the harvest store waste plant matter and burn
| it over the next season to keep the CO2 concentration in
| air good for plants and for you. It's a closed cycle if
| you eat/burn everything you grew each growing season, and
| you can keep the air CO2 concentration stable by
| adjusting how much waste matter you burn vs how much CO2
| is captured by the plants.
|
| You need about 2000 m2 of corn to feed one person over 1
| year and just 100 m2 of corn will capture the CO2 exhaled
| by that 1 person in 1 year. Assume we live in horizontal
| lava tubes 300m wide, let's say 10 meters of that tube
| per person to have some margin of error. That's <535 kg
| of CO2 in air in that section of the tube and ~8000 kg of
| CO2 captured in corn planted there the moment before
| harvest.
|
| It's doable IMHO. At least napkin math checks out.
| navaati wrote:
| Wow, I pity the poor astronauts that have to do science inna
| state of dizziness !
| xyzzy_plugh wrote:
| Interesting, I didn't know this about ISS. I've fought a
| tiring battle to get my CO2 levels below 500ppm consistently,
| and it's night and day compared to the 800-1200ppm I used to
| measure. Can't even imagine what 5000ppm is like!
| nolroz wrote:
| Have you felt benefits from getting your levels lower? What
| steps did you take? Do you have a sensor you recommend?
| sparker72678 wrote:
| Not the OP, but I've been using a model by Awair for a
| while now (looks like they've released a new product
| that's a bit more expensive since I got mine).
|
| I work in a very small office shed, and if I leave the
| door and window closed tight it will quickly get over
| 2000 ppm (45-60 min). At that point I'm typically feeling
| more tired, and a bit foggy.
|
| By keeping the window cracked I can keep the readings
| down in the 800-1100 range, and I feel much better.
| BackBlast wrote:
| Get some plants?
| Aspos wrote:
| Office plants can't absorb 1kg of CO2 per day
| tailspin2019 wrote:
| Also interested in the answer to this!
| dbsmith83 wrote:
| You can just open a window and circulate air in the home
| to lower CO2 levels. I use a uHoo sensor
| https://getuhoo.com/
| vkat wrote:
| How has the uHoo sensor worked for you?
| dbsmith83 wrote:
| So, I bought one and it was great, but then randomly the
| CO2 sensor seemed to stop working after a few weeks. It
| stayed at the exact same ppm level without changing for a
| while. I sent an email to customer support and they
| shipped me a new one for free, and didn't even require me
| to send back the old one. Haven't had any issues since.
| I'm pretty happy with it.
| Raz2 wrote:
| My CO2 sensor self calibrates to show 400ppm as outdoor /
| minimal concentration. I was very upset to find out that
| it's not correct. In the last 5 years outdoor concentration
| rose from ~400 to ~420. Guess my kids won't be able to
| maintain < 500ppm.
| CoastalCoder wrote:
| I remember discussing this a while back on HN, and one
| issue was that consumer-grade CO2 meters aren't reliably
| calibated.
|
| So just curious for my own designs, how certain are you
| about those ppm numbers you listed?
| eightysixfour wrote:
| I have tested quite a few against calibrated commercial
| hardware at this point and they're not as poorly
| calibrated for CO2 as you would think. The particulate
| counts and VOCs are usually only good for comparative
| measurements from the same device in my experience, and
| even then the drift is quite large.
| JohnJamesRambo wrote:
| All my CO2 meters read about the same as the one in my
| grow room that controls the CO2. I don't think that is a
| big problem.
| CoastalCoder wrote:
| Any chance you could share some of your findings? They'd
| be super helpful to some of us.
| mdp2021 wrote:
| I am desperately looking for one for the car, do you have
| anything to suggest?
|
| Also, I am finding products that seem to require an
| Android or iOS device to work: no. They must be
| independent. If they had a webserver, nice idea, but all
| connections should be unrequired and switchable to off.
| CoastalCoder wrote:
| You might need to specify which kinds of gasses or
| particles you need to measure.
|
| I would have assumed CO2 from the context, but since you
| mentioned cars I'm wondering if you mean CO, VOCs, and/or
| PM32.
| mdp2021 wrote:
| Correctly guessed, mainly CO2 (breathing). I did not know
| that CO can be relevant in the car. But of course, the
| more is evalued, the better. In fact, for example, I had
| similar concerns for CO for the house (free flames).
| CoastalCoder wrote:
| My understanding is that in a car, CO is normally a
| concern only if exhaust gas is somehow leaking into the
| passenger compartment.
|
| Unless your car has the fans off and the windows rolled
| up for a really long time, I'd be surprised if CO2 was
| something you need to worry about. Maybe if you're
| sleeping in it with the windows rolled up?
|
| CO in the house is definitely a concern. If you have a
| fireplace, woodstove, or furnace with a properly
| functioning chimney, you're unlikely to run into problems
| AFAIK. But people die every winter because they used a
| propane grill, or kerosene heater, or gas stove/oven in
| their house without proper ventilation. Or used a wood
| stove with ineffective / blocked chimney. So in colder
| climates having a functioning CO meter seems like a no-
| brainer.
| mdp2021 wrote:
| Exactly. In the car, it may happen in winter that you
| could be working for some time with little ventilation.
| You may at some point feel dizzy, and realize you would
| like a meter to get the feedback that can teach you be
| more aware of the air quality, to regulate the balance
| between letting the hot air inside escape and letting the
| fresh air (both senses) in.
|
| In the house, similar awareness could be beneficial.
|
| But I have not yet found a decent product. It is
| unacceptable that one is supposed to have a Google
| account or similar in order to read a ruler or configure
| a blender.
| CoastalCoder wrote:
| I'd like to share a thought on this, which you may find
| helpful. I apologize if it comes across as presumptuous;
| I'm not good at finding the right wording for this kind
| of thing. It's a cautionary tale from my own life that
| may or may not resonate with you.
|
| Sometimes I've had similar lines of questioning. Where it
| occurs to me that something might be a risk worth
| addressing, and so I'd better gather data until I'm
| confident everything is okay or that I'll have a way to
| notice when the risk becomes real.
|
| Every(?) time I've gone down that route, I later
| concluded that the concern really wasn't that big a deal,
| and that I'd just be hyper-focused on it because of
| anxiety or A.D.D. I.e., in the overall scheme of things,
| the true risks that deserve priority are pretty evident:
| good sleep and body weight, exercise, not smoking,
| keeping my finances in order, etc. I have a tendency to
| forget those primary issues when I start focusing on
| something that could, potentially, under some
| circumstances become a problem.
|
| When I go down those rabbit trails, I end up reading a
| lot of articles, buying some unnecessary stuff from
| Amazon, planning for a project that realistically I'd
| never complete, and just worrying a lot.
|
| If there's any takeaway from all this (for me, at least),
| it's "don't sweat the (probably) small stuff".
| OJFord wrote:
| Not GP (nor a metrologist) but 50% reduction is surely
| the important thing anyway, in a home setting, not the
| absolute figures? I don't think the curve could be much
| off, since they work by counting particles, so if it's
| reading high at 800ppm then it should be reading just as
| high at 500ppm right?
| CoastalCoder wrote:
| I agree that presumably less CO2 is better than more.
|
| I'm thinking that the _specific_ CO2 concentrations
| matter if one wants to relate the readings to various
| research on human mental performance.
| Jarwain wrote:
| if we figure out efficient methods for carbon capture
| planetside, couldn't we reuse those methods for any non-
| terrestial habitat?
| ajuc wrote:
| > It's likely that it will either be impossible or
| prohibitively expensive to keep CO2 levels at normal Earth
| standards.
|
| I think we shouldn't use orbital space station where space
| and energy is very constrained as model for lunar base (where
| space and energy will be quite easy to get by comparatively).
|
| Average person breaths out ~1kg of CO2 per day or ~400 per
| year [1]. Corn field absorbs ~4000 kg of CO2 yearly per 1000
| m2 [2]. The same 1000 m2 field will produce ~4000 ears or 320
| 000 kcal yearly [3][4]
|
| Assuming 2000 kcal for average person (so 730 000 kcal
| yearly) - we need 2000 m2 of corn fields to produce food for
| that person and just 100m2 to absorb CO2 from that person.
| Food will be a more important constraint in a self-sustaining
| base.
|
| That means if we build lunar base in the lava tubes (that are
| often over 300 meters wide and go on for kilometers), we can
| keep them self-sustainable at density of 1 person per less
| than 10 meters of the lava tube.
|
| [1] https://www.nrdc.org/onearth/waiting-
| exhale#:~:text=So%20bre....)
|
| [2] https://www.canr.msu.edu/news/corn_fields_help_clean_up_a
| nd_...
|
| [3] https://www.quora.com/How-many-ears-of-sweet-corn-are-in-
| an-...
|
| [4] https://www.nutritionix.com/i/usda/corn-1-ear-
| medium-6-0.75-...
| lazide wrote:
| That math seems a bit implausible if you look at it from a
| closed system perspective. For said 1000m^2 field, it has
| to get the carbon from somewhere to produce the food, that
| then powers 6 months worth of activity for said human. If a
| human via respiration can only provide a tiny fraction of
| it (per the inverse of the other statement regarding:amount
| of Co2 absorbed for the field), where does the rest come
| from? Decaying organic material? Soil? Both of those are
| problematic closed system wise.
|
| There is a lot of very dubious math in everything from
| 'amount of water consumed' and 'amount of carbon absorbed',
| etc. which if you dig into it really doesn't add up. This
| feels like one of them?
| jjk166 wrote:
| You would have to bring in enough carbon for the initial
| setup. Once you have enough material to grow the first
| crop, you will decompose previous crops to provide carbon
| and other nutrients for subsequent crops. In a closed
| system, none of that is being destroyed. In a real system
| you will get some losses (absorbtion by structural
| materials, population growth, leaks, etc) but these would
| be small compared to the overall amount, and easily made
| up with resupply at first and mined material over the
| long term.
| ajuc wrote:
| It's so ironically steampunk that one of the main things
| we will supply to space stations at first will be coal :)
| And that each of them will need a big biofuel-fired
| powerplant just to produce food :)
| ajuc wrote:
| That just shows that the actual problem in a base with
| self-sustaining food production will be the inverse - not
| enough CO2 to produce food instead of too much of it to
| breath.
|
| To solve this you need initial biomass (or CO2) and then
| after the harvest you burn or otherwise decompose
| everything you didn't eat to close the cycle and get your
| CO2 (and some of the energy) back.
|
| The easiest way to achieve that initial CO2 concentration
| would probably be to bring about ~3.5 tonnes of coal per
| person, burn it with oxygen mined from lunar soil
| generating energy for your initial base-building (24 MWh
| of heat about 40% of which you can convert to electric
| energy) and capturing the resulting 8 tonnes of CO2 for
| agriculture.
|
| Of course you'd bring reasonably pure carbon, not the
| cheap dirty stuff we dig from the ground with heavy
| metals and sulphur in it. Also catalyst would be needed
| to avoid producing carbon monoxide.
|
| Another concern is how much volume of air we need in
| these tubes to keep the atmosphere breathable and
| suitable for enough CO2 to supply plants.
|
| Assume the tube is a cylinder 150m in radius and 10 meter
| in height (height is horizontal here ;) ). That's 700 000
| m3 of air which should weight about 857 500 kg. At 410.28
| ppmv CO2 in air we can calculate that 0.0623240117 % of
| the air mass should be CO2, which is ~535 kg in that
| 10-meter section of the tube. This is a long way off the
| 8 tonnes of CO2 needed to grow the plants, but they don't
| want all of that CO2 at once anyway - so we store the
| waste plant matter from harvest and burn it slowly over
| the year to keep CO2 concentration in air breathable.
|
| We could also separate the atmospheres for plants and for
| people to optimize CO2 ppm for each, but that makes math
| more complicated :)
| umvi wrote:
| Would colonizing the moon and making it have an atmosphere with
| plants and such make it super dim at night? I imagine the lunar
| surface covered with plants would not reflect light nearly as
| well.
| dbcooper wrote:
| There is no carbon on the moon. Try sustaining anything without
| that element.
| jokethrowaway wrote:
| If you want to bring 8B people on the moon, you may as well
| transport some carbon.
|
| The Apollo took 51hrs to get there, unmanned missions took 4-5
| days
| jacquesm wrote:
| If you are bringing 8B people to the moon you _are_
| transporting some carbon. And O2, and H2, and a bunch of
| calcium and various spore elements such as some iron and
| manganese, etc.
| vermilingua wrote:
| I don't think disassembling colonists is going to be a very
| popular way to source carbon. /s
| Kichererbsen wrote:
| pretty sure sooner or later you're going to have to
| figure out what to do with defunct colonists anyway and
| disassembling them is not the worst option...
| ccozan wrote:
| Soylent green all the way!
| jacquesm wrote:
| No, not really, more like closed eco-systems end up
| recycling everything, including bodies. Planet Earth is
| one such eco-system.
| sneak wrote:
| Depends on what kind of colonists, tbh.
|
| Half the books I've read about lunar colonies would
| probably disagree. :D
| ant6n wrote:
| "Eat the inners!" ?
| jacquesm wrote:
| Unless they live forever this will solve itself. At a
| guess most of the carbon and water that you are consuming
| has been re-cycled a couple of times already, and I'm
| pretty sure that at least some of that was part of a
| human configuration at some point in its past.
| mkl wrote:
| If we had the ability to transport large numbers of people to
| the moon and set up civilisation, we'd probably also have the
| ability to bring a minable carbon-rich comet or two into lunar
| orbit or smash them into the surface.
| BurningFrog wrote:
| If you have that ability, you can also smash a comet into any
| city on Earth.
| ericmay wrote:
| Yea so we'll have to just not do that
| stevespang wrote:
| No worries, the "dictatorships for life" in China and
| Russia will figure a way to weaponize comets and
| meteorites . . .
| jerf wrote:
| There is no way around that. If you sit down and seriously
| wargame what a space civilization looks like, in real space
| with no Star Trek shields, you get some interesting
| results.
|
| One of the results that is really hard to avoid is that if
| there is a large-scale space civilization around, using the
| entire solar system... planets aren't really militarily
| defensible. Without some sort of technology like shields or
| something that don't seem plausible, they're just sitting
| ducks. Following along from there, that tends to mean that
| the planet-bound are going to try to be _very_ highly
| controlling of the space civilization for as long as
| possible. They 'll be torn between the high levels of
| wealth the space civilization is sending back down, which
| will rapidly become completely necessary to sustain their
| life style, and the fact that every ship in space is a
| deadly weapon. If you can get to the asteroid belt in a
| reasonable period of time, you can accelerate from there at
| a rate that is going to be uninterceptable by the time it
| gets to Earth.
|
| There's a reason why there's a lot of sci-fi about the
| space settlers fighting Earth for independence. It's not a
| terribly difficult analysis to see that as a highly likely
| outcome. I've only sketched it here.
|
| (As another for-instance... it becomes highly advantageous
| for Earth to do everything in its power to make darned sure
| those space colonies can't survive independently, up to and
| including full intelligence penetration to kill any
| research attempt to come up with alternate sources for
| hydrocarbons or nitrogen or complex manufacturing. But the
| economics and politics inexorably push towards doing more
| stuff in space for those in space, because it's a _lot_
| cheaper than the shipping costs, and as the space-bound get
| more wealthy and more numerous, eventually they can start
| smuggling equipment and find places to extract these
| resources even so....)
| BurningFrog wrote:
| I expect asteroid exploration to be _heavily_ restricted,
| since anyone who can move an asteroid also has more
| destructive power than a nuclear bomb.
| hulitu wrote:
| We can export CO2 from earth.
| robjan wrote:
| Earth still needs the carbon, just preferably not so much in
| the air.
| merpnderp wrote:
| The ocean floor is the final end game for surface carbon.
| Unless we dig it up and send it to the moon!
| tzs wrote:
| There was some evidence in 2020 that there may be more carbon
| than we thought on the moon [1]. I don't know if there have
| been further developments on this.
|
| [1] https://phys.org/news/2020-05-carbon-emissions-moon-
| theory-b...
| rbanffy wrote:
| The best thing is that when you extract oxygen from aluminium,
| iron, and magnesium oxides is that you get oxygen AND materials
| to build your spacecraft. All in a place where you can take off
| much easier than from Earth.
|
| The Moon is the most valuable real estate between Venus and Mars.
| Cthulhu_ wrote:
| I saw a Scott Manley clip earlier about a newish rocket company
| that was building a launcher using rotational energy (flinging
| rockets towards space, their idea being that they can do away
| with the first stage of a rocket entirely). I wonder if a
| device like that would be able to launch a payload from the
| moon back to earth without needing fuel (besides maybe small
| maneuvers / course corrections).
| rbanffy wrote:
| This is a bit more flexible than a rail (which can only throw
| payloads on a single direction), but the Earth is always more
| or less on the same place in the sky from the Moon, so a rail
| /linear induction motor is probably the simplest way to do
| it. No need to have moving parts and, if the rail is long
| enough, the acceleration can be quite mild.
|
| For safety, I'd not build it aimed directly at Earth, but
| require some trajectory corrections not to miss the planet.
| Otherwise it's just a weapon.
| hutzlibu wrote:
| "Otherwise it's just a weapon. "
|
| Everything that is in space and big enough and can be
| roughly guided, can be a devastating weapon.
|
| Which is why I love the idea of peaceful space exploration
| and am not so happy about the latest developements to arm
| the space again.
| rbanffy wrote:
| > Everything that is in space and big enough and can be
| roughly guided
|
| When it's guided, you may be able to see it coming, see
| the jets for changing trajectory, and it can evade an
| impactor designed to turn it into a lot of smaller pieces
| that will burn up in the atmosphere. If it's just a rock
| covered in F22 paint it'll be a lot harder to see before
| it hits.
| datameta wrote:
| True up until the plasma sheath has burned away the radar
| absorbant coating and then generates a magnitude or more
| EMF than the object does at ambient space temperature.
| rbanffy wrote:
| By that time there isn't much you can do to prevent
| impact.
| datameta wrote:
| Certainly you can. At that point it is on final
| trajectory and we simply have to put a missile under the
| object heading straight up. It depends on the type of
| rock we're talking about. If it's sufficiently large to
| be highly destructive upon splintering then we are in the
| realm of science fiction.
| rbanffy wrote:
| If it comes in at 10 km/s you'll have about 10 seconds to
| do that.
| RobertoG wrote:
| From the moon, the 'traditional' idea is a mass driver:
|
| https://en.wikipedia.org/wiki/Mass_driver
|
| First time I heard about it was in:
|
| https://en.wikipedia.org/wiki/The_High_Frontier:_Human_Colon.
| ..
| rbanffy wrote:
| The big advantage of the rotating launcher is that you can
| aim it towards other targets, not only the Earth. You can
| take your shuttle from LEO to the Moon and then board the
| big spaceliner in her maiden voyage (because that's the
| last time it'll be on a planetary surface) towards Mars.
| h2odragon wrote:
| Where you aim the ground launcher (given you're aiming
| "over the horizon" at least) doesn't have a lot to do
| with where you wind up in orbit.
| datameta wrote:
| Would it not take more dV to cirularize if we fired it
| straight up?
| rbanffy wrote:
| The better aligned to the desired trajectory you launch,
| the less delta-V you need to get where you want to be. If
| we launch a payload and, in order to get to where you
| want it'll need to do a u-turn, our launcher isn't
| helping.
| datameta wrote:
| Precisely. Therefore a 45 or 30 degree launch angle gets
| more of the velocity in the orbital vector.
|
| Unless you are talking about launching it at lunar escape
| velocity directly at earth orbit.
| rbanffy wrote:
| We were discussing the installation of these on the Moon
| as a way to launch spacecraft. A straight rail would be
| aimed at a fixed point, but a centrifugal launcher could
| release its payload at any point and send it in any
| direction (as most interesting destinations in the solar
| system are on a single plane).
| [deleted]
| agent008t wrote:
| Anybody interested in this should play Policenauts. It is
| an amazing game by Hideo Kojima of Metal Gear fame. It
| features lots of details like that about life in space,
| very fleshed out, and is just altogether one of the best
| games ever made.
|
| There is also an amazing English translation, and a blog on
| how it was done:
| https://lparchive.org/Policenauts/Update%2042/
| nerpderp82 wrote:
| Lets all move to the moon in as a space palace and give the earth
| 50k years to recover. We can come down and vacation and do
| restoration work.
| jokethrowaway wrote:
| Good to know.
|
| There is also some water on the moon - and some hydrogen we could
| use to make water.
|
| Now we just need to deal with the temperature ranging from
| -173,+127 and then we can build a nice moon base.
| rbanffy wrote:
| That's what caves are for. As long as you are not exposed to
| the Sun, you're fine.
| varelaz wrote:
| Technically moon has enough oxygen to sustain 8B for indefinite
| time, while you have energy to convert it. If you're going to use
| oxygen from rocks, why not use it from CO2 that we produce
| 29athrowaway wrote:
| Which is what is done by life support modules in space stations
| no?
| varelaz wrote:
| AFAIK on space stations right now CO2 is just removed, oxygen
| is restored from water, but I could be wrong.
| nashashmi wrote:
| The air mixture of earth has only 20% oxygen. This helps in
| keeping fires to a minimum.
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