# What would you make in space? [closed]

In a near-future scenario what sort of manufacturing might occur in space? There are several potential advantages to a factory in space. Space provides hard vacuum, micro-gravity, consistent solar power, large amounts of raw materials from asteroid mining, and the ability to vent as much hazardous waste as your heart desires. But what manufacturing processes could actually make use of these features?

In our near-future scenario we still rely on chemical rockets to get into orbit and to putter around the solar system. We have captured a few asteroids and comets and nudged them into orbits around the Earth.

What products could be made more cheaply or efficiently in space? And could the benefits ever outweigh the cost of transporting the necessary people and/or materials into orbit?

• WIkipedia: Space manufacturing, while listed as outdated, might be a good starting point. It handwaves away a few really important aspects though, like launch cost. As far as I know, nobody has yet come up with anything that is economically advantageous or even feasible to produce in space, though it's certainly possible that manufacturing of certain items may benefit in other ways from a microgravity, vacuum environment. – user Jun 11 '15 at 8:29
• The cost of sending anything into space is such that it would have to be something you could do nowhere on the planet and it would have to be very valuable. And by valuable, I mean that the production of diamonds wouldn't be worth the effort because of the eventual decline of the market price of diamonds. Yes, I do mean more valuable than this. A mandatory requirement to such a factory would almost certainly be a space elevator. – Neil Jun 11 '15 at 12:10
• @Neil One thing you are overlooking is that space manufacturing would be really useful if you were getting your raw materials from sources in space. Especially if you are manufacturing things for use in space. Say you need a rock drill for asteroid mining. And the rock drill weighs 100 pounds. If you don't have a space elevator then it's gonna be expensive to send that drill to orbit. So make it in space, from materials mined in space, for use in space. Spaaaace. – AndyD273 Jun 11 '15 at 13:46
• "What products could be made more cheaply or efficiently in space?" Ball bearings. Perfectly round ball bearings. They turn up in all sorts of machines. I think I may have first read of this proposal many years ago in a book by Arthur C. Clarke – Lostinfrance Jun 11 '15 at 15:35
• I despise the misnomer "micro-gravity". It is more accurately known as "free-fall". The objects erroneously described as being under "micro-gravity" are in fact under quite a bit of gravity, or they'd fly off into inter-stellar space rather than orbiting the earth or the sun. But because everything is falling at roughly the same rate, there is weightlessness. – Monty Harder Jun 11 '15 at 17:32

The biggest advantage of manufacturing stuff in space is that it's already there.

If you build a spaceship part on Earth, now you have to ship that part out of Earth's gravity well. That's hideously expensive to do - one of the big goals of space exploration is to get transportation down to under 1,000 dollars per pound. So if you make a 50-pound spaceship part, you automatically add at least $50,000 to the cost for transporting it to space. Make that same part in space, and you don't have that cost. Now think about that price difference in say, a pound of screws from Earth vs a pound of screws from space. As for other techniques: 1. You should use robots and Waldos for most direct manufacturing. Your humans will stay in their safe rotating habitat 99% of the time, remotely controlling bots that do the actual work. This avoids most issues with zero gravity and bulky space suits - the only time they need those is if all the waldos break down and you absolutely need a human on-site. 2. While pollution is less of a concern, you don't want to literally just throw your trash into space. It might literally come back to hit you. It would be better to define a large area on a nearby body - probably the moon - as trash central, and require factories to send their trash on orbits that will impact there. This still keeps pollution disposal very cheap, while not cluttering orbits. Certain pollutants (like radioactives) might need other disposal techniques - maybe send those out to the asteroid belt on very slow, low-energy orbits. 3. I can't speak authoritatively on this, because as far as I'm aware no one's actually tested it. But I suspect that there will be manufacturing techniques that work extremely well in microgravity, especially in materials composition. But we don't have any details on which those would be. • Ideas for part three: Being able to melt stuff with out it having to be in contact with any thing would be a good start. All those things that have stupidly high melting points and are very hard to process on earth suddenly become quite easy. No need for a crucible to hold it. Just put it there and heat it up (Induction, IR, etc) – Wil Selwood Jun 11 '15 at 19:20 • For the trash, why not just send it drifting directly into a star? radioactive or not – user2813274 Jun 12 '15 at 0:19 • I mean, space is empty. We don't make screws on the ground because that's where the screw press is. We make screws on the ground because there's not a lot of iron ore in orbit. If you can capture asteroids, however, all that changes. Anyway, we don't mail trash to stars because it's really hard to throw trash hard enough to get it to hit the sun. – Resonating Jun 12 '15 at 0:23 • @user2813274 Any trash will be moving at the same speed around the Sun as Earth does. If you push it towards the Sun then you're only changing it's orbit to a more elliptical one, still in Earth's path. What you'd need to is completely stop it from rotating; which might be more expensive then sending it to infinity. – csiz Jun 12 '15 at 10:48 • @csiz No, you just need to slow it enough to re-enter the atmosphere, that is very cheap (90 m/s delta v -> space.stackexchange.com/questions/12011/…) – Caridorc Jun 14 '16 at 19:58 Just my 2 cents, but a vacuum isn't an advantage it's a disadvantage. It's hard to work in a vacuum - humans need to wear bulky suits and humans are still often needed for set up and repair. Also pistons that rely on fluid would need to be air tight. Space is also full of the occasional cosmic ray and solar storm, so it's not an easy place to work. I'm not sure micro-gravity is much of an advantage either. It's hard to work if the slightest force propels you away from the object you're trying to work on. Low gravity could well be an advantage, but micro-gravity - I think that's a disadvantage. OK, that out of the way, there's no shortage on what they would mine if asteroid mining was cost effective - Wiki has a page on it. http://en.wikipedia.org/wiki/Asteroid_mining#Financial_feasibility But the issue is 2 fold. 1) cost and 2) guaranteed return. Wiki makes the point that one particular asteroid "16 Psyche is believed to contain$1.7×10^{19}\$ kg of nickel–iron, which could supply the world production requirement for several million years"

When we mine iron on earth, we dig through thousands of tons a day. The trucks alone are as big as a small building and the factories that melt and separate the minerals from the earth - enormous. To do asteroid mining, you have to try to minimize the equipment needed cause launching things in space is very expensive. If it takes 100 years or longer to get equal return on investment - that's not attractive to an average business cause they get killed on interest payments alone.

So it's a fun idea, but, for now at least, not practical. I mean, if one company gets an asteroid and a million year supply of Iron - what's to stop a 2nd company from, 20 years later, doing the same thing but with better technology - that leaves the first company holding a big loss.

The real trick with space mining is to get the technology to send something in space that can build machines in space - and while that might sound terminatorish, that's really not what I mean. What I mean is, you can't send drilling equipment up to an asteroid the size of Wyoming, what you need to do is send equipment up to Wyoming sized asteroid that can build drilling equipment from the asteroid material, so you can increase production quickly. Right now, we don't have that technology. It's similar to the Mars problem. What we really need is the ability to build things fairly quickly on Mars if we're going to settle there and right now, we don't have the means to do that. Setting up a colony on Mars with today's tech would be very slow, and probobly would lead to the death of the colonists.

on Today's tech, it's very hard to see how the benefits would outweigh the costs for asteroid mining especially since the process can be copied by someone else the instant it becomes profitable and the tech is improved.

But long term, the benefits of mining something as simple as Iron in space is obvious - because ultimately, it's more energy efficient and cost effective to build things in space than to keep sending stuff from earth into space. . . .but we're not there yet technology wise. How long it will take for that to happen, that's hard to say, but at some point, with improving technology, I think it's sure to happen, and when it does, mining for basic stuff (Iron, water, nitrogen, carbon, oxygen) and for more exotic stuff (Platinum, Iridium, etc) and possibly helium, which we don't think of as valuable, but it could become valuable if Fusion ever gets figured out. I'm sure it will make sense eventually, but perhaps, mostly not to send back to earth, but for building stuff in space.

at least, that's my thinking on the subject.

• Most of modern manufacturing advantages come from conforming as much as possible to standard processes, since the cost for machines to do so would be greatly reduced. Doing anything in zero gravity would be have to be rethought because you can't just stick something on a conveyer belt. It could be advantageous, but it simply isn't because of how we've evolved industrially. – Neil Jun 11 '15 at 12:03
• Nitpick: it's not called "Wiki". – Kevin Jun 11 '15 at 14:59
• I call it Wiki. Anyway, I also wasn't so much going for a definitive statement on the subject but just my 2 cents - thoughts from my wandering mind so to speak. I think we all agree it's not cost feasible now. It could be at, some point, but really not now.. 10 years seems a bear minimum, I think it will be longer before any real space mining goes on. Maybe we'll see some exploratory crafts just to test available materials. – userLTK Jun 11 '15 at 15:28
• Much of the first part of this answer ignores the fact that much of manufacturing these days isn't done by humans banging on things with hammers; instead, robots are heavily used in mass production. For them (barring hydraulics, as you did point out) vacuum largely doesn't matter. The downsides of micro-gravity are easily negated by simply designing your robots to hold on to what they're working on. Micro-gravity may have significant advantages for many processes (e.g. anything to do with crystalline structures), however, although the prohibitive costs means those aren't fully explored yet. – Kromey Jun 11 '15 at 16:54

So: supply and demand has made something economical to make in space. But there's a catch: space is very expensive to go to. It has a lot of special properties but it is fundamentally an expensive place to visit, so whatever you make in space has to be incredibly valuable(and not just decoratively. It has to be used for something and there can't be good alternatives).

(It occurs to me that human nature is kind of awful and therefore there will be people who sell space tomatoes for exorbitant prices specifically because they're exorbitantly expensive and rich people will buy them to impress one another, but that's boring.)

There's one thing space (well, orbit) has that Earth doesn't have. Well, the other way around. It's gravity. Space has microgravity environments for minutes or hours at a time, and there's no way to do that for more than a few seconds on the ground. Hard vacuums, radiation, energy, isolation are all doable(if expensive) on the ground.

And what can you do without gravity? Grow crystals, incredibly perfect ones. Isolating your crystal pods from vibrations and convective forces as the crystal forms lets crystals form with much fewer deviations or defects. The crystal growing chamber has a seed crystal and some solution, and all it needs is to cool down very slowly. That's really easy to build with zero moving parts and no maintenance required, so living spaces for human beings(expensive and breakable) is minimized and productive crystal aging vats are maximized. Superconductors are strange metal crystals that benefit from extreme regularity, perhaps space is the only place they can grow stable enough to work at room temperature.

Maybe they're just growing giant germanium-doped silicon crystals for really sensitive radio receivers. Or giant perfectly regular crystals to build gravity interferometers for detecting cloaked spaceships by their gravity signature. Giant protein crystals for X-ray diffraction. Or giant rock candy, or all of the above.

Starship fabrication

I would only build things in space that I could build using resources already available in space and that aren't required or designed to ever enter a gravity well or atmosphere. Once a certain tech level is reached, large space-going vessels that aren't intended to ever make planetfall would likely fit that requirement.

Due to the hostile environment in outer space—hard vacuum, significant radiation, and lack of gravity or atmosphere—life support costs alone will naturally make any construction there more expensive. However, the energy cost to lift something out of a gravity well is also significant and will remain so. Space elevators will be volume-constrained, even though they will greatly reduce the cost per mass unit of getting stuff into orbit.

Therefore, the only case in which the savings from space-based construction will outweigh the costs is for huge, heavily automated endeavors that require massive amounts of raw materials, and then only when the vast majority of those materials can already be harvested without entering a gravity well.

Aside from that, the only things you'd want to make in space are things that require microgravity to make. Currently, that list consists solely of large, symmetric, and perfect crystals, although technological development could obviously change that.

Solar energy collectors is an area of active research. See http://en.wikipedia.org/wiki/Space-based_solar_power

Although if we are putting asteroids into LEO this might become less attractive, one of the major issues with space based power stations is degredation due to space junk.

I have a somewhat low-tech sounding, but totally practical, suggestion: ball bearings.

Currently, in order to make high-quality ball bearings, the metal is stamped into a form, made slightly too large (to account for the mass that will be lost in the next step), ground and polished for hours on end to make it round and smooth, and it still doesn't come out as perfect as if one simply extruded a precisely-measured quantity of molten metal into a micro-gravity environment and let it find its own shape. The process, because it's so simple, could be handled almost completely autonomously.

Now, as others have noted, the cost of launching materials into orbit in order to manufacture stuff is usually too prohibitive to bother with. But if these asteroids you mention can be mined for iron and other necessary elements (which I guess is the point) then the materials are already on hand, and the process becomes reasonably cheap. You then only need to find a way of getting the finished product down to Earth where it can be used (parachutes, heat shields, the usual).

If I could make one other suggestion: if you allow nuclear (as opposed to chemical) rockets in this scenario, everything starts to make a lot more sense. Nuclear rockets aren't some far-out imaginary technology we'll never live to see, either, but are theoretically very possible, and an active area of research within the space-tech field. They're probably closer on the horizon than asteroid mining, frankly. With a basic design, you could assume a 2-3x improvement in rocket thrust-to-weight ratios, which makes things like mining (and relocating) asteroids that much more practical.