[HN Gopher] Factories in Space
___________________________________________________________________
Factories in Space
Author : rvnx
Score : 84 points
Date : 2023-05-30 13:30 UTC (9 hours ago)
(HTM) web link (www.factoriesinspace.com)
(TXT) w3m dump (www.factoriesinspace.com)
| TheFattestNinja wrote:
| Slightly related: SMBC's guys have recently published a book on
| related topics, claiming it's got a lot of bibliographical
| research in it (disclaimer: haven't read it yet.)
| http://www.acityonmars.com/
| JumpCrisscross wrote:
| > _Benefits: Earth: Materials and products that can not be
| manufactured or are much better_
|
| This is mostly guff from what I've seen, at least in the next
| hundred years.
| RC_ITR wrote:
| One of the things I've always been curious about - gravity is
| still _very much_ exerting force on things in orbit, it 's just
| that the object is moving along the perpendicular axis just as
| fast.
|
| For someone smarter at physics than me - I get why this 'feels'
| like weightlessness/0G, but does it actually have that impact
| when it comes to physical manufacturing?
|
| If it does, wouldn't terrestrial factories that have some sort
| of inertial roller coaster in them (akin to a vomit comet) be
| the cheaper/better answer?
|
| EDIT: I think a lot of people are missing the point of my
| question here. Remember, objects in orbit _are_ accelerating
| because they are changing direction.
|
| This is different that being motionless in a far field with
| microgravity.
|
| But in practice, does that acceleration matter for physical
| manufacturing?
| f154hfds wrote:
| The 'feeling' of weightlessness is pretty much an indication
| of 0 (micro) gravity. Gravity always exerts a force, the
| problem is on Earth we have ground exerting an equal and
| opposite force contrary to gravity. When you feel weightless
| whether in orbit or just falling off a cliff you're in free
| fall experiencing none of that upward opposition to
| gravitational force.
|
| For example, it was very hard to replicate the moon's gravity
| when training pilots to land on the moon. How do you 'fake' a
| different gravity on Earth? It's pretty hard to do:
| https://www.youtube.com/watch?v=aw8kRZEvh_s
|
| EDIT: to your question about centripetal force, either you
| experience acceleration or you don't. Since gravity is in
| equilibrium with centripetal force relative to movement
| around Earth you shouldn't get acceleration from this.
| However, you will get micro g's from rotation of the station
| itself, etc.
| [deleted]
| RC_ITR wrote:
| >centripetal force relative to movement around Earth you
| shouldn't get acceleration from this.
|
| If there is no acceleration, then how are objects changing
| direction?
| f154hfds wrote:
| The ISS will do a 360 degree rotation every 90 minutes to
| maintain its orientation relative to the surface of the
| Earth. This will result in bodies inside the ISS slowly
| rotating in the opposite direction of that rotation.
| However, this is unrelated to acceleration - these are
| constant angular velocities. The micro gravity I believe
| is the result of atmospheric drag, and the occasional
| boosting required to account for it.
|
| Also I should add, it is confusing thinking about 0g,
| because obviously bodies in a gravity well are
| experiencing a gravitational force. Really we're talking
| about 0 acceleration, where g is the acceleration due to
| gravity. In orbit this g acceleration is cancelled out by
| centripetal acceleration to produce 0 acceleration, or
| free fall.
| heavenlyblue wrote:
| Aren't bodies inside ISS rotating with it? Or are you
| implying that the rotation of ISS is not inertial but is
| constantly propelled by engines? If engines are driving
| it constantly, why is not constantly accelerating it's
| rotation?
| wildzzz wrote:
| Assume the earth is a perfectly smooth sphere with a constant
| force of gravity and there is no air resistance:
|
| Throw a ball parallel to the ground. Now throw it faster. It
| will land farther away than last time, right? Keep throwing
| it faster and faster and the ball will keep landing further
| and further away from you. Eventually, you throw it so fast
| that the ball flys through the air, all the way around the
| earth and lands back at your feet from behind you. You've
| just completed a single orbit around the earth. Keep throwing
| it faster and faster until the ball flies past you forever
| without touching the ground. This is a little hard to imagine
| because this speed is tremendous and something no one can
| really experience on earth.
|
| The ball is constantly falling away from that direction you
| threw it originally due to gravity. Gravity is always acting
| on the ball and is always acting on any satellite in space as
| well. Gravity doesn't change that much for how high
| satellites fly. However the speed of the ball is just so such
| that it will never change from the height you originally
| threw it from.
|
| Catch the ball out of the air and throw it just a little
| faster this time. The ball will still orbit but will pass
| over your head this time. The speed of the ball dictates the
| orbit altitude. Mass also factors in as well but not much for
| something so small. Grab it out of the air and keep throwing
| it faster and faster and eventually, the speed is able to
| overcome gravity and the ball leaves Earth's gravity
| entirely.
|
| In Low Earth Orbit, there is just enough atmosphere to
| provide some minor air resistance that will actually slow
| down that ball you threw. As the ball slows, the orbit
| altitude decreases. As the altitude decreases, the atmosphere
| gets thicker and air resistance increases which makes the
| ball slow even more. It gets so slow that it can't maintain
| an orbit any more so it lands on the surface. If you attach a
| small rocket engine to the back of the ball, you can
| occasionally turn it on to maintain the exact speed you need
| for that orbit. If you use the rocket engine to make the ball
| go faster, you can raise the orbit. Rotate the ball 180deg
| and now you can use the rocket engine to slow the ball to
| lower the orbit.
|
| Astronauts in space constantly have gravity on them but they
| are moving at such high speeds that gravity is not able to
| change their altitude. They are always "falling" just like
| the ball but never land. They float around inside their
| spacecraft because those too are falling constantly.
| lloeki wrote:
| IOW orbital mechanics is the art of falling whilst
| constantly missing the ground
| nradov wrote:
| Terrestrial factories for round lead shot do something like
| that. Just drop molten lead from the top of a tower and it
| will form a near perfect sphere as it falls weightless.
|
| https://en.wikipedia.org/wiki/Shot_tower
| narag wrote:
| _I think a lot of people are missing the point of my question
| here._
|
| I believe it's you who are missing the point. Acceleration is
| irrelevant, it's how it's transmitted that matters. You feel
| gravity because the ground prevents you from falling exerting
| an opposite force, that is transmitted mechanically along
| your body.
|
| There is no difference between free falling and no gravity
| except in monster gravitational fields like the one close to
| an event horizon where differential gravity (tide) could torn
| you apart. In any other situation you can safely assume that
| all the points in an object are pulled uniformly.
| RC_ITR wrote:
| Direction is a fundamental aspect of acceleration, no?
|
| I'm also not asking about what our brains are conditioned
| to feel. I am simply asking - is the constant acceleration
| of orbit fundamentally different than no acceleration, even
| if both would feel the same?
|
| No-one has answered that in a compelling way.
|
| Because to be clear - in one, no forces are being applied
| and in another, there are forces being applied (how else
| would you change directions?).
| narag wrote:
| _I 'm also not asking about what our brains are
| conditioned to feel._
|
| Brain can't feel without senses input.
|
| _is the constant acceleration of orbit fundamentally
| different than no acceleration...?_
|
| No.
|
| _how else would you change directions?_
|
| You don't. You keep going straight, space is deformed by
| gravity.
|
| But even if you look at it like in classical mechanics,
| the effect is applied uniformly to every particle of your
| body, so it makes no difference.
|
| Ask yourself this: how do you feel gravity right now?
| JumpCrisscross wrote:
| > _the object is moving along the perpendicular axis just as
| fast_
|
| Orbit is free fall. It's equally correct to describe a
| falling object's weightlessness as moving as fast as gravity.
|
| > _get why this 'feels' like weightlessness/0G, but does it
| actually have that impact when it comes to physical
| manufacturing_
|
| No, it's the first postulate of Einstein's theory of special
| relativity [1]. Free fall and the absence of gravity are as
| indistinguishable as acceleration and the its presence.
|
| [1] https://en.m.wikipedia.org/wiki/Postulates_of_special_rel
| ati...
| monkaiju wrote:
| "This is the missing piece to speed up development for the
| exciting Star Trek-like future."
|
| Unbelievable misunderstanding of ST to think markets, or
| 'economic drivers' in their terms, would lead to anything like
| ST... The whole point of ST is that they are in communism or
| anarchism even. Nobody on the Enterprise was getting paid
| yboris wrote:
| Seems like 3D printing organs in space would be really useful and
| might make financial sense given their importance to people.
| bell-cot wrote:
| Any particular reason to believe that "in space" would make 3D
| printing of organs substantially easier?
| LispSporks22 wrote:
| I imagine a whole new wave of "innovation" for VC, it's like
| Uber, but in space
| [deleted]
| jjoonathan wrote:
| Oh, there will probably be several booms and busts. Stocks
| will go to the moon, and then back to earth, and then to
| the moon, etc. So it goes.
| pixl97 wrote:
| Because gravity is a bitch when making squishy things. They
| like to collapse under their own weight before they can
| harden. Imagine a pipe that is rigid when fluid is flowing
| though it, but collapses and sticks together when none is
| present. There would be a massive amount of difficult in
| attempting to print/build said pipe under pressure.
|
| In zero gravity you don't have to worry about pressurizing
| it, but you do exchange a new set of difficulties.
| JumpCrisscross wrote:
| > _gravity is a bitch when making squishy things. They like
| to collapse under their own weight before they can harden._
|
| It's much cheaper to master fluid suspension.
| [deleted]
| birracerveza wrote:
| It would be awesome to have space elevators all over the globe
| and create a LEO network for factories and logistics.
|
| A man can dream.
| grawp wrote:
| LEO is not accessible by space elevator at all. If you got off
| at ISS height you would just fall down. Good for basejumping
| though. And no you wouldn't even need heatshield, just rugged
| EVA suite.
| consumer451 wrote:
| I have always wondered if one could be strapped into a Falcon
| 9 fairing half and ride that down in an EVA suit. Coolest
| ride I can imagine.
| zabzonk wrote:
| basically, "starship troopers", the book
| Arrath wrote:
| A cowboy hat is mandatory attire for this scenario.
| e_y_ wrote:
| The elevator itself would need to extend past LEO into
| geostationary orbit, but you should be able to get off the
| elevator in LEO space.
|
| As you're going up the space elevator, you would also be
| picking up horizontal velocity as you ascend. At ISS
| altitudes there would be enough atmospheric particles to slow
| you down once you got off, but it would take a while;
| probably on the order of years. Base jumping would not be a
| good idea.
| leashless wrote:
| Surprisingly, I _know a great song about this!_
|
| Unexpected, I know. But
| https://www.youtube.com/watch?v=gFufOGZBwFM try that for size.
| Isn't it beautiful?
|
| The well paced blips of the factory ships Slide past our orbit's
| brink Like a swarm of bees in the girder trees Come to our
| flowers to drink
|
| And the earth is clean as a springtime dream No factory smokes
| appear For they've left the land to the gardener's hand And they
| all are circling here
| dvh wrote:
| Show me a prototype that works in Arizona desert, then I believe
| it.
| nickelcitymario wrote:
| How is that comparable? I apologize for this bit of sarcasm,
| but last I checked, Arizona has both air and gravity.
| jandrese wrote:
| I think he's saying that if you can't do it in the desert
| then you shouldn't be talking about trying to do it in orbit.
| Work through the problems before you add in the launch costs
| and all of the other complications.
|
| This is also what I say to people who propose a permanent
| Mars colony. They should be re-creating the Biosphere project
| right now and making it a success before the rocket is ready
| to go. There are a lot of problems that are seemingly still
| unaddressed with the whole project.
| nickelcitymario wrote:
| Fair enough. But with a biosphere, that makes sense. Mars
| has gravity and an atmosphere, so a biosphere on Earth is a
| smart project to resume.
|
| I'm not saying we shouldn't test everything we can. We
| should, absolutely. But we also have to accept that the
| absence of gravity and operating in a vacuum are two major
| factors we could never adequately test on Earth.
| neovialogistics wrote:
| Wouldn't delivery of products from factories in space to
| customers on Earth start to warm the atmosphere beyond our
| desired range directly - or at least as you begin to scale?
| zabzonk wrote:
| i like the idea of factories in space - just doubt the
| possibility. for example, can you imagine constructing a modern
| chip fab in orbit? it's hard enough down here.
| ben_w wrote:
| Depending on what you're doing, it can be easier. No need for a
| clean room for the chips or an ultra-hard vacuum chamber for
| your extreme-UV laser when you're already in the cleanest
| hardest vacuum around.
|
| I read somewhere that some specialist types of fibre optic
| cables already make sense to make in orbit just for the
| microgravity, but I don't know if that was a proposal to try it
| or if they already do...
| wongarsu wrote:
| > I read somewhere that some specialist types of fibre optic
| cables already make sense to make in orbit just for the
| microgravity, but I don't know if that was a proposal to try
| it or if they already do...
|
| They are testing various prototypes on the ISS since 2019.
| Apparently the fibre quality is great and better than what we
| can make on earth [1], and the current prototypes are about
| automating the process.
|
| I suspect that once access to space (and space stations)
| becomes cheap enough we will identify a lot of manufacturing
| processes where gravity is detrimental, and where the end
| product is valuable enough that shipping to and from space
| makes sense.
|
| 1: https://www.nasa.gov/directorates/spacetech/flightopportun
| it...
| photochemsyn wrote:
| All the equipment would need to be radiation-hardened,
| though, and radiation-hardening is pretty expensive, although
| maybe easier in low-Earth orbit.
|
| https://en.wikipedia.org/wiki/Radiation_hardening
| dotnet00 wrote:
| Considering that most production in space (with even near
| future launch costs) would mainly only be worthwhile if the
| resources were also obtained from space, I don't think
| radiation shielding will be as much of an issue, since if
| you're doing ISRU, you can gather enough mass around the
| facility to handle shielding.
|
| For chip fab in particular, since current processes require
| a lot of water, and water is very good as radiation
| shielding, such a facility in space would probably just
| store water in the walls.
| aziaziazi wrote:
| Well problem solved then ! Just find _a lot of_ water in
| space not too far from earth, or a cheap way to create it
| in orbit.
| dotnet00 wrote:
| Yeah, that's why I said that most things aren't worth
| producing in space without the ability to obtain
| resources from space. Kinda pointless if you just have to
| launch the water from Earth.
| idiotsecant wrote:
| It turns out space is full of big floaty rocks that you
| could hollow out and put your factory inside.
| heavenlyblue wrote:
| And how many of these big floaty rocks are close enough
| go Earth?
| ianburrell wrote:
| Also, the equipment either needs to be made to work in
| vacuum or have to maintain atmosphere for it.
| wongarsu wrote:
| In (very) low earth orbit you can get by without radiation
| hardening. The ISS uses HP zbooks (and before that
| Thinkpads) and apparently they only really modify cooling
| and power, without any changes for radiation hardening.
|
| Seems like they are reliable enough for their job and just
| need the occasional reboot. For more critical systems you
| could probably get by with three computers voting on the
| result, and if they disagree the outlier gets rebooted (a
| fairly standard setup in aviation and space)
| Majestic121 wrote:
| Could be the walls of the hangar to be hardened, not
| necessarily the whole equipment. I'm not sure if it would
| be less expensive though
| themanmaran wrote:
| It's just heavier that way. The easiest way to rad harden
| things is to stick them in a big lead box. But that's not
| ideal for shipping things to space.
|
| Alternatively I've seen some companies successfully rad-
| hardening from the software level. Effectively software
| that is tolerant to random bit flips.
| JumpCrisscross wrote:
| > _easiest way to rad harden things is to stick them in a
| big lead box_
|
| Or work in a permanent shadow. Cosmic rays are easier to
| deal with than solar radiation.
| shagie wrote:
| This makes power generation a bit more challenging.
|
| There are sun synchronous orbits (and the orbit at the
| dawn/dusk terminator is an interesting one -
| https://en.wikipedia.org/wiki/Sun-synchronous_orbit ),
| but there isn't an easy orbit around the Earth such that
| it is always in shadow... or rather, that's the Earth/Sun
| L2 point... which is where the JWST is. At that distance
| you lose the magnetic shielding of the Earth (and makes
| it even more expensive to get materials to and from it).
| marcosdumay wrote:
| The factory needs to be shielded. You can't really harden
| fine processes.
|
| Right now, space manufacturing makes sense for exactly
| nothing. With enough research, it can in theory make sense
| for almost anything.
| ianburrell wrote:
| Still need clean room for humans that needed to operate it.
| If have completely automated it, then don't need clean room
| on Earth. The vacuum chamber is cheaper than the laser. Both
| reasons are saving millions at the expense of billions.
|
| Fabs are probably the worst factories to put in space because
| of how much human adjustment they require. Also, the
| equipment is expensive and delicate, and redesigning it to
| work in space would be enormously expensive. It would be
| ruinous to lose one. They require tons of chemicals to work,
| that have to come from Earth, and produce a lot of nasty
| waste, which still have to dispose of in space.
| m0llusk wrote:
| Use robots instead of humans maybe.
| wildzzz wrote:
| One thing I question is all of the materials that originate
| from petroleum, like polymers. I'm sure there's sufficient
| quantities of ore on other planets but anything made from
| polymers is going to only come from Earth. Are we just shipping
| the precursors to the moon and Mars or are we sending polymer
| products (Kevlar, Kapton, Tefzel, pretty much Dupont's entire
| high reliability catalog) to these places? Many synthetic
| polymers still rely on precursors that come from petroleum. It
| would require significant changes in how we produce many of the
| products we take for granted on Earth to be able to make them
| off-earth without just shipping massive tankers full of
| chemicals.
| zabzonk wrote:
| yes, really my first question is not "how do we make chip
| fabs?", but "how do we make insulated wire?"
| nradov wrote:
| In theory you can synthesize petroleum, polymers, or any
| similar chemicals out of elemental hydrogen / carbon / oxygen
| / nitrogen / etc. It just takes enormous amounts of energy,
| some expensive catalysts, and an large heavy physical plant.
| So in practice we're not going to be able to do chemical
| manufacturing in space at scale for several centuries at
| least.
| m4rtink wrote:
| I think it depends - the lack of Earths gravity could make it
| possibly much easier or much harder.
|
| Definitely an interesting problem to look into. :)
| codetrotter wrote:
| Totally expected this to be AI generated photos of factories
| floating in space before I clicked the link.
|
| Similar vibe to cats on keyboards in space, you know?
|
| https://www.knowyourmeme.com/memes/cat-on-a-keyboard-in-spac...
| mcphage wrote:
| I was hoping it was a new game in the Factorio / Satisfactory
| genre :-)
| adhesive_wombat wrote:
| Oh my God please no. Zero-G Factorio would ruin my life, lose
| me my job and probably result in complete breakdown of human
| relationships.
| tomca32 wrote:
| Well there's Factorio Space Exploration mod which can
| easily take months to go through
| https://mods.factorio.com/mod/space-exploration
|
| Sorry
| mdaniel wrote:
| Just in case you weren't aware, Dyson Sphere Program (https:/
| /store.steampowered.com/app/1366540/Dyson_Sphere_Prog...) is
| Factorio in space and I actually prefer it for reasons I
| can't exactly articulate. It's labeled as Early Access but my
| experience is that it's more stable an fun than some
| "production" games I've played
| peteradio wrote:
| Love the idea of factories in space. We need to separate the
| human from the supply chain interaction with raw and noxious
| materials and if we can do that in space we absolutely can
| terrestrially.
| JumpinJack_Cash wrote:
| This is Bezos vision (or the vision of the guy he paid to craft
| it for him) , anyway at least it gives some coherence to the
| space effort.
|
| When people are talking about living on Mars or on the Moon, sane
| people automatically categorize them as crackpots, whereas moving
| heavy industry in orbit with the help of automation at least sets
| a path for some sort of ROI which is not the ridiculous "hop in
| the rocket bro we are going to Mars lmao"
| HeyLaughingBoy wrote:
| https://gradprograms.mines.edu/space-resources-graduate-prog...
| bryanlarsen wrote:
| Note that this is the end goal of Jeff Bezos and his company Blue
| Origin, who was a Gerard O'Neill groupie when they were both at
| Princeton. AKA "move dirty industry into space and make Earth a
| garden planet".
|
| Bezos does not expect to live long enough to see it happen, but
| he claims to want to put the building blocks in place.
|
| https://en.wikipedia.org/wiki/Gerard_K._O%27Neill
| uoaei wrote:
| His entire series of enterprises has been about complete
| vertical integration. One part of why his favorite show ever is
| _The Expanse_.
| mym1990 wrote:
| Just curious, what does vertical integration have to do with
| The Expanse?
| uoaei wrote:
| The entire show is about political tensions that result
| from expanding corporate dominance and private ownership
| into industrial heavy mining operations like those out in
| the Belt, with all the attendant cost-cutting and
| consequent torture of the peons that that entails. Reminds
| heavily of stories heard from within Amazon warehouses.
|
| Amazon's push to dominate retail markets via Basics, etc.,
| and the anti-competitive practices he enables, only serves
| to portend an obvious conclusion that Bezos wants to own
| not just the marketplace but every component of goods
| production.
| mym1990 wrote:
| Gotcha. It is also one of my favorite shows(and I am far
| from a space theme enthusiast), but I think I focused
| more on the protovirus and what not, I should go back and
| re-watch it again!
| cjbgkagh wrote:
| I don't understand how it's even remotely feasible to move
| dirty industry into space? It's hard enough to build industry
| on Earth. Where would the biproducts (dirt) go? Wouldn't it be
| far easier to make factories cleaner on Earth? This sounds like
| someone who has now truly lost the plot.
| pnut wrote:
| I've come to the opposite conclusion, that taking heavy
| industry off planet is a godsend, because it allows
| capitalism's stagnating growth curve, fuelled by resource
| extraction with no regard to externalities, to plausibly
| continue indefinitely, with no environmental consequences -
| and the wealth poured back onto earth.
| mym1990 wrote:
| You mean: "and the wealth poured back into Bezos pockets".
| bequanna wrote:
| Wealth isn't a zero sum game.
|
| New resources, new ideas, new efficiencies benefit all of
| us.
| mym1990 wrote:
| Sure, my comment was a bit hyperbolic, but 'all of us' is
| certainly far from the truth as well.
| nickelcitymario wrote:
| > Where would the biproducts (dirt) go?
|
| On the website, they suggest that these byproducts, i.e.
| waste, could effectively be dumped into space, where the
| solar winds would carry it out to the asteroid belt.
|
| I have no expertise to determine if this would ever be
| viable, but seems like they do at least answer this
| particular question of yours.
| cjbgkagh wrote:
| I guess that could work, I did not think of that. Not sure
| if it greatly improves viability but venting into the solar
| winds I guess could be an option. At low earth orbit
| wouldn't most material fall back down to Earth, it's not
| like they'd be vending hydrogen. And a very high Earth
| orbit would incur even greater costs of getting material
| into space. It still seems bananas.
|
| Edit: I checked and solar wind starts at 60K km so there is
| no solar wind at LEO and 60K km is way beyond geostationary
| where it is already considered too expensive to bring
| things back to Earth.
| wombatpm wrote:
| The better bet is to process raw materials in space and
| send refined products down to earth. Would you rather
| have strip-mining and smelting occurring in space or on
| earth? Daniel Suarez had a lot of fascinating ideas in
| Delta-V
| nickelcitymario wrote:
| I had the same questions! But again, this is where my
| knowledge fails me. For example, if you release C02, how
| far away from earth would you need to be for it to not
| get caught in Earth's gravity?
|
| Still, it's a fascinating idea.
| cjbgkagh wrote:
| The more I look into it the less feasible it looks. My
| initial assumption is reflective of the peer comment that
| anything remotely heavy won't have enough solar wind drag
| to get it out of Earths gravity well.
|
| Just to be in the solar wind alone you'd have to be
| outside the magnetosheath ~60K Km at its closest point,
| 35K Km is geostationary orbit which costs $10K kg to get
| to with falcon 9. And now you'd have to send up a whole
| falcon 9 in order to bring the non byproduct mass back to
| Earth which would defeat the purpose of venting CO2 to
| begin with. For those who don't know it takes roughly the
| same delta V to bring things back down as it took to send
| them up.
| wongarsu wrote:
| Anything within Earth's sphere of influence [1] (about
| 90000 km) will initially be in orbit around Earth. Unless
| you give it a kick that puts the highest point of the
| orbit further away from earth than that.
|
| Unless you shoot stuff away with railguns, the relevant
| question might be "at which point are solar winds a
| bigger factor than drag". I guess it's highly dependent
| on the exact gas. We lose Helium that way from earth
| (buoyancy brings it up, where solar winds catch it), so
| at some height it should work for CO2.
|
| It only really works for gases though, and then only for
| things that stay reasonably gaseous in orbit (low
| pressure and large temperature swings). For any solid or
| liquid you have to worry about it crashing into you on
| one of the orbits, and at orbital speeds tiny things can
| impact with a lot of energy.
|
| 1: https://en.wikipedia.org/wiki/Sphere_of_influence_(ast
| rodyna...
| DoreenMichele wrote:
| I don't know the answer to that.
|
| Though I'm wondering: If manufacturing were done on the
| moon, would it be safe and feasible to haul some wastes
| to the lunar equator during the cold of night and let it
| burn up when daytime temps naturally exceed the boiling
| point of water from solar power alone?
| [deleted]
| pugworthy wrote:
| I wonder what the impact would be on astronomy, whether
| space based or terrestrial?
| antisthenes wrote:
| Pretty cool website and concept, but unfortunately mostly a
| delusional pipe dream until we develop fusion-based propulsion
| that makes orbital travel dirt cheap.
|
| Here's a good summary of why it's mostly pipe dreams at the
| current tech level:
|
| https://www.nasa.gov/mission_pages/station/expeditions/exped...
| JumpCrisscross wrote:
| > _until we develop fusion-based propulsion that makes orbital
| travel dirt cheap...here 's a good summary_
|
| The tyranny of the rocket equation describes the exponential
| fuel cost of lifting propellant, with propellant, out of a
| gravity well.
|
| One workaround is non-propellant launch [1], _e.g._ an orbital
| rail gun. (Fusion propulsion is still tyrannical because you're
| carrying your propellant.) The other is in-situ resource
| utilisation, _i.e._ not lifting out of a gravity well.
|
| [1] https://en.m.wikipedia.org/wiki/Non-rocket_spacelaunch
| antisthenes wrote:
| Ah, yes.
|
| The response that just hand-waves a bunch of really hard
| problems or invents tech that doesn't exist.
|
| I get it, HN has a lot of tech-optimists, but these responses
| are very tiring. Has there been legitimate significant
| progress on orbital guns or space elevators since 2012?
| jandrese wrote:
| Wasn't the "super cheap fusion launch" predicated on
| discovering a non-Newtonian rocket engine? As long as
| you're suffering under the third law the idea of a super
| cheap launch is a pipe dream. This is also why concepts of
| reaching distant solar systems by maintaining 1G of thrust
| for the entire trip don't work. Plug the numbers for that
| into the rocket equation and even with absurd ISP values it
| requires more mass than is available in our solar system
| for a trip to even just Proxima Centauri.
|
| The only maybe possible exception would be to pump so much
| energy into your reaction mass that it gains a significant
| amount of mass from relativity, but even that is
| engineering in the "it's probably easier to build a space
| elevator" realm.
| JumpCrisscross wrote:
| > _response that just hand-waves a bunch of really hard
| problems or invents tech that doesn 't exist_
|
| The tyranny of the rocket equation is irrelevant to the
| problem of extraterrestrial manufacturing, at least in the
| short term. It's all ISRU.
|
| > _Has there been legitimate significant progress on
| orbital guns or space elevators since 2012_
|
| Actually, yes. I'm sceptical of SpinLaunch. But they are
| making real progress on the technology, even if they aren't
| the ones to complete the package to orbital delivery.
| grepLeigh wrote:
| Check out "3D Printing in Zero G" experiments on the ISS for the
| origin story of space manufacturing:
| https://www.nasa.gov/mission_pages/station/research/experime...
|
| The company "Made in Space, Inc" responsible for creating the 3D
| printer, since acquired by Redwire.
| https://en.m.wikipedia.org/wiki/Made_In_Space
| grishka wrote:
| I was just thinking that some manufacturing processes and
| research techniques require deep vacuum that needs very expensive
| equipment on earth, but comes for free and in effectively
| unlimited volume in space.
|
| Also we only need a small manufacturing-capable space station to
| build a larger space station out of materials mined from
| asteroids.
| Ciantic wrote:
| We have to start by assembling in space first. SpaceX's Lunar
| Starship is a little bit like that. They have to launch tankers
| to orbit and refill the lander.
|
| I can imagine someone making rockets from multiple separately
| launched parts that are then assembled in space. It would allow
| to use well tested rockets to launch smaller parts instead of
| trying to build a huge rocket at once.
| JumpCrisscross wrote:
| > _We have to start by assembling in space first_
|
| You need to solve the material-cost problem first. Either a
| space gun / elevator or ISRU. Otherwise, assembling on the
| ground is cheaper for everything but the most massive objects.
| (At which point a constellation or fleet usually makes more
| sense.)
|
| > _would allow to use well tested rockets to launch smaller
| parts instead of trying to build a huge rocket at once_
|
| Bigger rockets have moderate economies of scale. Optimising for
| a particular launch vehicle doesn't make sense in the long run.
| gshubert17 wrote:
| ISRU - In-Situ Resource Utilization
|
| The farther humans go into deep space, the more important it
| will be to generate products with local materials, a practice
| called in-situ resource utilization.
| dotnet00 wrote:
| At this point it isn't just SpaceX's Starship, but in general
| the direction Artemis is heading in, since the secondary lander
| design (from Blue Origin, Lockheed Martin et al) that was
| recently chosen also uses in-space refueling and is designed
| with Lunar ISRU in mind.
|
| Shelby finally retiring has been a great boon for NASA's human
| space exploration programs.
|
| Also, technically the Lunar Gateway would fit your second
| point, considering that it's split into a separate habitation
| module and power+propulsion element.
| Retric wrote:
| We've had space assembly for decades, just look at the ISS
| which both consists of many modules and used regular fuel
| deliveries to maintain orbit etc.
|
| Manufacturing seems possible but is several orders of magnitude
| more difficult because many processes on earth simply aren't
| viable without access to earths vast array of manufacturing
| infrastructure, organic chemicals, or even gravity.
| 9dev wrote:
| I guess all we need now is an Epstein drive ...
| hef19898 wrote:
| Only as a steping stone to Hoersch-Kessel ion engines. For FTL,
| I propose Kearny-Fuchida jump drives.
|
| Honestly, I just wanted to nerd out.
| giantrobot wrote:
| I understood every word of that. We can be friends.
| [deleted]
| hef19898 wrote:
| Accepted!
|
| Funny, how easy it can be to retain those totally
| unimportant facts, isn't it? I credit my English to a huge
| extend to stuff like that, after almost all those books
| came in English.
| giantrobot wrote:
| I might remember more made up history of settings like
| BattleTech and Star Wars than I do actual real world
| history. I think I retain facts better the closer in
| proximity they are to lasers.
| louissan wrote:
| wasn't there a quote in the soft cover Mechwarrior RPG
| saying something along the lines of "whatever happened to
| the Universe while Einstein wasn't looking?"
| giantrobot wrote:
| I don't see that quote on the cover of either 1st or 2nd
| edition of MechWarrior unfortunately. It does sound like
| something that would have been on some BT book however.
| hef19898 wrote:
| I'd have to take a look at my library to verify! I love
| the Kearny-Fuchida backstory so, they were basically
| ridiculed crack heads, until decades after their death
| people jumped to New Earth (?) on the THS Pathfinder (?).
| sc68cal wrote:
| ah, another Battletech aficionado on the site
| hef19898 wrote:
| I just hope there are plenty more!
| shagie wrote:
| Given the funding of the BattleTech: Mercenaries
| kickstarter, I think that's a fairly safe assumption.
| (It's also _really_ impressive consider the age of the
| game... I wonder if my Ral Partha miniatures are still
| around somewhere).
| hef19898 wrote:
| Mine are, they get expensive on eBay so... The last
| Battletech game is propably one of thebgakes I played the
| most, according to Steam statistics!
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