Why Spacecraft Of The Future Will Be Extruded

It’s been fifty years since man first landed on the Moon, but despite all the incredible advancements in technology since Armstrong made that iconic first small step, we’ve yet to reach any farther into deep space than we did during the Apollo program. The giant leap that many assumed would naturally follow the Moon landing, such as a manned flyby of Venus, never came. We’ve been stuck in low Earth orbit (LEO) ever since, with a return to deep space perpetually promised to be just a few years away.

Falcon Heavy Payload Fairing

But why? The short answer is, of course, that space travel is monstrously expensive. It’s also dangerous and complex, but those issues pale in comparison to the mind-boggling bill that would be incurred by any nation that dares to send humans more than a few hundred kilometers above the surface of the Earth. If we’re going to have any chance of getting off this rock, the cost of putting a kilogram into orbit needs to get dramatically cheaper.

Luckily, we’re finally starting to see some positive development on that front. Commercial launch providers are currently slashing the cost of putting a payload into space. In its heyday, the Space Shuttle could carry 27,500 kg (60,600 lb) to LEO, at a cost of approximately $500 million per launch. Today, SpaceX’s Falcon Heavy can put 63,800 kg (140,700 lb) into the same orbit for less than $100 million. It’s still not pocket change, but you wouldn’t be completely out of line to call it revolutionary, either.

Unfortunately there’s a catch. The rockets being produced by SpaceX and other commercial companies are relatively small. The Falcon Heavy might be able to lift more than twice the mass as the Space Shuttle, but it has considerably less internal volume. That wouldn’t be a problem if we were trying to hurl lead blocks into space, but any spacecraft designed for human occupants will by necessity be fairly large and contain a considerable amount of empty space. As an example, the largest module of the International Space Station would be too long to physically fit inside the Falcon Heavy fairing, and yet it had a mass of only 15,900 kg (35,100 lb) at liftoff.

To maximize the capabilities of volume constrained boosters, there needs to be a paradigm shift in how we approach the design and construction of crewed spacecraft. Especially ones intended for long-duration missions. As it so happens, exciting research is being conducted to do exactly that. Rather than sending an assembled spacecraft into orbit, the hope is that we can eventually just send the raw materials and print it in space.

Some Assembly Required

It took more than 20 years and 36 Space Shuttle launches to assemble the International Space Station in its current form, but added together, all of the modules only have a mass of around 400,000 kg. If we only had to deal with total mass, that is if it was somehow possible to liquify a space station and cart it to orbit in a more dense form, commercial rockets like the Falcon Heavy or Blue Origin’s New Glenn could do the job in a handful of flights.

Obviously, there’s no technology that would allow us to reconstitute a functioning space station or Mars transfer vehicle from a payload fairing full of goo. But even with current fused deposition modeling (FDM) 3D printing technology, researchers believe we should be able to create large orbital structures. Imagine launching a rocket filled to payload capacity with a store of feedstock and a robotic printer that can extrude and assemble structural members from it.

Robotic arms are used to assemble the 3D printed beams

With such an arrangement, a single heavy-lift rocket could potentially hold enough raw material to print a truss structure far larger than anything humanity has ever put into space. Once the printed frame was completed, subsequent launches could deliver and install equipment such as solar arrays and living modules for the crew. While the design would still require substantial assembly on Earth, being able to autonomously construct the spacecraft’s “skeleton” in orbit would offer immense time and cost reductions.

It might sound like science-fiction, but that’s precisely the capability that Made In Space of Mountain View, California was recently awarded a nearly $74 million contract from NASA to demonstrate. The company plans to launch a satellite, named Archinaut One, within the next few years that builds on the 3D printing techniques they pioneered aboard the International Space Station in 2014. Once in orbit, it will construct two beams that extend 10 meters (32 feet) out from both sides of the craft. If successful, Archinaut One would have a “wingspan” to rival that of the Space Shuttle; despite riding into space inside the diminutive 1.2 meter fairing of a Rocket Lab Electron.

Printing a Wet Workshop

Original “Wet Workshop” Sketch

During the development of the Apollo program’s massive Saturn V rocket, Wernher von Braun had a remarkable idea. Rather than discarding the second stage of the rocket once its propellants had been expended, what if it could be used as a stand-alone space station?

He reasoned that its cavernous liquid hydrogen tank would offer the astronauts more than enough room to live and work in, all they needed to do was vent the remaining gas into space. A crew launched on a second rocket would then open a hatch in the top of the tank and insert a large “equipment module” that had fixtures, equipment, and a docking port.

This hypothetical station, called a “Wet Workshop” since it would travel to space filled with liquid hydrogen, unfortunately never left the drawing board. In the end, NASA opted to outfit the third stage of Saturn V as a self-contained space station while it was still on the ground, and launch it directly into space. This so-called “Dry Workshop” eventually became Skylab, America’s first space station.

While it might not be as “Wet” as Wernher von Braun envisioned all those years ago, 3D printing could eventually allow us to construct space stations using a similar principle. Companies like Lockheed Martin and Relativity Space are already 3D printing propellant tanks for rockets here on Earth. If Made In Space is successful in their attempts to print truss structures in orbit, a space-optimized version of this tank manufacturing technology may be a logical next step.

If hollow cylinders of sufficient strength and diameter can be printed in space, they could have hatches installed on both ends and be pressurized. After checking them for leaks, human crews could install the internal equipment and fixtures necessary to turn them into functional modules for a station or deep space vehicle. These printed modules could be made in arbitrary lengths to suit the intended mission, including lengths far greater than could be contained within the payload fairing of any operating or proposed rocket.

The Moon, and Beyond

Structures 3D printed in orbit might well play a part in returning humanity to the Moon, and eventually, moving on to Mars. The potential cost savings of being able to launch rockets filled to the brim with raw building materials is simply too great to ignore. There are certainly technical challenges ahead, but nothing that seems insurmountable given the research already conducted on FDM printing aboard the ISS.

But no matter how humans get to our nearest celestial neighbor or the Red Planet, they will almost certainly find 3D printing to be an invaluable tool. While we’re still learning the ropes of printing in space, we already have decades of experience when it comes to additive manufacturing on solid ground. The reduced gravity of the Moon or Mars won’t fundamentally change the physics of FDM, and the local materials might even be a suitable “filament” for fusing into large structures.

So whether it was used to build the space station where they trained, the vehicle they left Earth in, or the structure where they conducted their surface research, one thing seems absolutely certain: 3D printing is going to be an invaluable tool for humanity’s future offworld.

59 thoughts on “Why Spacecraft Of The Future Will Be Extruded

  1. Why is Blue Origin even mentioned in the same breath as SpaceX? They have spent billions on a toy rocket, a mocked up lander, a rocket engine – but they are still earth bound. SpaceX has done the impossible with a lot less money and tinkering.

    1. ‘SpaceX has done the impossible’
      That’s a bit………generous given the number of patents they licensed or bought in addition to proofs-of-concept that have gone before spaceX’s recent achievements.

        1. That’s still a bit generous, given that they haven’t actually done it.

          The main claim to fame for SpaceX is hiring Tom Mueller who was already developing and building the cheaper rocket technology under NASA/JPL funding. The rest is unsubstantiated hype – like the tail landing rockets, which technically work as proven by others before SpaceX, but don’t actually show any cost savings until they manage to fly each booster at least a dozen times – if they survive/work that long – which they haven’t actually done.

          In fact the ones currently in use aren’t even designed to be re-used enough times to break even, and whenever they need to launch a bigger load to a higher orbit, the booster is lost (no fuel left over for return) so the odds are against them ever actually being able to recycle enough of them for actual savings.

          The actual bread and butter of the entire company is still Tom’s affordable rockets, and the other stuff is just Elon Musk playing rocketman to attract investors and keep the share value from collapsing.

          1. Hmm, I’d like to see your proof of “if doesn’t break even until it has flown a dozen times”. The engines are the most expensive part of the rocket. The Merlin engines of a Falcon 9 are estimated to cost $2.1 million a pop, or about $19 million for the first stage. The total first stage cost is estimated at $30 million. Fuel for that stage is cheap (certainly less than $1M), so unless the referb costs of the stage are more than about $25 million (and given they don’t even bother re-paining it then this is highly doubtful) then your assertion is bunk.

          2. Your clearly wrong in most every aspect. You’re bureaucracy red tape driven liberal like democrat incompedance is why NASA and Boing failed at building an inexpensive reusable launch vehicle. Tesla brilliant think outside the box engineering gets the credit for being the first to succsessfully build and fly an allready proven far less expensive per launch rocket. Tesla hired some of the best non beuracrat engineers in the world to realize Elins Musks dream, but a dream that is now a reality slapping your ego driven jelouse face. Get over you’re self imposed negative clearly wrong incompedant innovation stifling statements about SpaceX’s allready proven low cost launch system that is allready succsessfull and the envy of engineers and the world.

          3. Your operating on very outdated information. As of 2017, SpaceX COO Glen Shotwell said cost of refurbishment was less than half of building a new Falcon 9. It’s only gone down since then, as turn around from landing to relaunch has steadily been reduced.

            Needing dozens of flights to pay for themselves was an old estimate, Block 5’s reusability has exceeded expectations.

            But as you seem to have a person vendetta against Musk and his companies, you’ll probably claim that’s it’s all a lie to defraud the investors.

          1. If the critical component is the will to do it, then SpaceX has been spectacularly successful already, and you have to give Elon Musk at least a bit of credit for that! I get tired of hearing how everything SpaceX has done has been thanks to the work of others. Welcome to science and technology – EVERYONE depends on the work of those who came before them. “Shoulders of giants” and all that.

            As the article points out, the REAL critical component is getting funding, and Musk has been quite successful with that as well.

          2. >you have to give Elon Musk at least a bit of credit for that!

            Anyone can make hype. The question is will people believe it? Musk’s main credit is having enough money that people take him seriously even if they don’t believe a word of what he’s saying, because they know at least he’ll be paying (with other people’s money).

            Every generation has its P.T. Barnum.

  2. “…we’ve yet to reach any farther into deep space than we did during the Apollo program”

    Well, “we”, have reached quite far since the Apollo program, just not in the first person perspective. I’m all for exploring space, but the reality is that sending living, breathing humans much beyond LEO adds a level of complexity that simply can’t be justified by the increased capabilities. The idea of sending people to float in airships in the clouds of Venus is probably the most absurd example of this – they still couldn’t go to the surface, so their purpose would simply be to remotely monitor robotic lander vehicles, something we can do just fine from Earth as evidenced by the Mars rovers. Yea, you’d get a reduced delay between the surface and the people above… but again, is that worth the added complexity?

    Now I’m not down on people eventually reaching other planets and beyond, but I think we have to be realistic about where we stand at the moment. I suspect a program of sufficient complexity is beyond the focus, dedication and resources of a species facing the issues we currently face, culturally, temperamentally, economically, politically and otherwise.

    1. When your robot melts in a matter of hours, a reduced delay in communicating with it could be very valuable.

      I think human colonies on the moon or mars are both feasible right now, at least from a technological standpoint.
      Self sustaining colonies are probably not feasible right now, and ironically it’ not power generation, or warp drives or any of that other high tech stuff that’s the problem… it’s food and it’s water.

      building structures in space is a solved problem… see the space station. Creating a self supporting ecosystem in a bottle that can support human life…. that’s a massive challenge that we’ve only started to scrape the edge of.

      1. You can send an awful lot of robots for the cost and mass associated with a human mission to Venus. Not only are there no 200 lb monkeys along for the voyage and return trip, there is no return trip.

          1. Hey, I did, pretty much exactly two years ago I was thinking of raising an urgent “SAVE CASSINI !!!” kickstarter to take control and have it land on, say, one of the moons of Saturn where the artifact could be collected by a future civilisation. But, what did they do instead? Crashed it, purposely CRASHED it into the planet itself. Well I just hope those JPL folks were happy about that.

        1. Humans though, are inherently based on personal experience. Sure, robots can go and do these things cheaper and safer, but you loose that “Human” context which is so incredibly important.

          When it comes down to it “Cost” is a human made artificial limitation that is holding back pretty much everything. But there are things that said cost shouldn’t be a factor, but then again, Americans are so vehemently opposed to anything that could be remotely considered “Socialist” or “Communist” it makes your mind boggle.

          It makes me wonder what the rich are going to do when they have all the money, No one is buying anything because there is no one left alive because they couldn’t afford to eat or get medical care, and the planet is cooking itself to death. At least they got their money huh!

      2. keep in mind that because of the advances in non-silicon semiconductors, we might actually be able to build a rover that could function in the stupidly high temperatures until it depletes its energy source…

      3. “When your robot melts in a matter of hours, a reduced delay in communicating with it could be very valuable.”

        So you’re saying ice robots aren’t a good idea?

    2. AI could be used for task that is affected by delays e.g. navigation That technology is being developed for vehicles.
      As for long term self sustained food outside of Earth, it won’t be potatoes.

      >Liu Hong, chief designer of Yuegong-1, said the test marked the longest stay in a bioregenerative life support system (BLSS), in which humans, animals, plants and microorganisms co-exist in a closed environment, simulating a lunar base. Oxygen, water and food are recycled within the BLSS, creating an Earth-like environment.

      >The volunteers grow wheat, strawberries and other plants. There is small amount of pre-stored pork and chicken. The main vitamin source for the volunteers are yellow meal worms raised in the cabin. They are roasted, ground and mixed with flour to make buns and pancakes.

    3. I think that beyond “not being down on people eventually reaching other planets and beyond”, you should realize that the overriding goal will always be to GO there. It will never be enough to have remote eyes and ears in far-away places. We have learned a lot from robotic explorations, but ultimately, these have been exercises in learning some of the lessons at lower cost than by direct human exploration. But what all of this learning goes to is a human presence.

        1. I agree. I think a LEO space station is more realistic at least in the near term as a shipyard. As others have mentioned we can use some sort of cannons with additional boosters to launch supplies to it and use more conventional rockets to ferry the needed personnel. IIRC, Gerald Bull had the same ideas of using big guns to launch payloads to space for cheap(er).

          Anyhow, I hope there’s a plan to build an off-earth shipyard to launch satellites and space vehicles from.

          P.S.: And, if it comes with a concave section to fire a super powerful laser beam from, then so be it. (c:

      1. Current thinking is that the moon has large deposits of water that can be made into fuel, plus minerals that can be used to make the structure of a vehicle. This will make it much cheaper in terms of resources to assemble a deep space vehicle than LEO

        1. Sounds like current thinking doesn’t know what it’s talking about. Neither about making water into fuel (yeah, yeah, I know about electrolysis) nor mining.

      2. The Moon and its (albeit low) gravity give some notable advantages to building stuff as oposed to microgravity. More importantly, there’s a bunch of material that could be used to build the craft, in LEO you only get what you bring.

        1. You will need an army of humans to gather materials and build a rocket. You will need to have living accommodations and feed them. No savings there. The only way to pull this off is to have an army of robots doing the work. We’re not there yet.

  3. ” If we’re going to have any chance of getting off this rock, the cost of putting a kilogram into orbit needs to get dramatically cheaper.”

    Railgun. :-)

    “But even with current fused deposition modeling (FDM) 3D printing technology, researchers believe we should be able to create large orbital structures.”

    Origami structures.

    “The reduced gravity of the Moon or Mars won’t fundamentally change the physics of FDM, and the local materials might even be a suitable “filament” for fusing into large structures.”

    Might change design though. When things like gravity and aerodynamics aren’t as big an influence one can be more flexible.

    1. There are proposed rocketless launch systems that will not turn humans Into jelly.

      If you have an evacuated tube with a cable in it, and you get that cable up past orbital velocity, the structure will levitate. Then, you can use a magnetic clutch to have the cable apply traction force to a payload,a right through the walls of the the evacuated chamber of lofchamberandthe chamber and accelerate the payload to launch speed.

      There are plenty of issues to be worked out, of course. For example, if the cable stops, the structure comes down, and anything launching humans will need to be a good 100 or so km from base to apex, so over 200 km in total (figures from memory, and may be wrong). So the structure is pretty large.

      But, the energy costs to put an object into orbit are absurdly low, if it’s not taking the fuel with it. A 1 kg object moving at low earth orbital velocity has a kinetic energy of about 30.4 MJ. A gallon of gas has about 120 MJ. I’m not saying we will ever get to space on a liter of gasoline, but I suspect that space tech will really “take off” only when we have a practical rocketless launch technology. W

      you are hauling the fuel with you as part of the package, there is a cascading complexity .. you need a lot more fuel, because it needs to lift itself, and the payload. You need fancier engines, because, to get that lift, you need to burn a lot of fuel in a very short time. So you need tanks that are rigid and light. And you need a stiff structure that can stand the dynamic pressures .. and you need a fancy control system etc. etc. It’s amazing that it can be done at all, and even more amazing that so much of the cost has been eliminated in recent years. But rockets will never be cheap. Rocketless systems, on the other hand, might be incredibly cost effective.

      1. “If you have an evacuated tube with a cable in it, and you get that cable up past orbital velocity, the structure will levitate.”

        Sorry, but you tripped the nonsense alarm three times in one sentence.

  4. The BFR that SpaceX is developing should do the trick, should it not? I would think that if you plan on putting 100+ humans inside and have room for entertainment space, then the BFR it is. We are definately getting closer! FutureFantastic.net

  5. There’s already a design for making long truss beams in space from compactly stored materials. The prototype used four rolls of flat metal. Three were creased lengthwise to 60 degrees while the fourth was wrapped around in a spiral to make a triangular truss. Being triangular it would resist twisting. A fifth roll to wrap the other way would make a fully triangulated triangular truss that would be very stiff in every direction.

    If the metal strips had round holes pre punched at regular intervals it would reduce weight without sacrificing stiffness, and would allow very easy attaching of other stuff. Pop a Rivnut into a hole wherever something needs attached. For EVA installation of Rivnuts, it wouldn’t be difficult to make a spacesuit friendly tool that has swappable nosepieces, each with a Rivnut threaded onto it. Stick those onto a magnetic bandoleer. Easier than attempting to wrangle small Rivnuts with spacesuit gloves and a standard install tool. The nuts would be screwed onto each tool nose inside the station or spacecraft before each EVA.

    That brings up another item future space stations and ships need. A small airlock for tools, equipment, and materials. Instead of having to carry *everything* needed during an EVA out the big airlock with the astronauts (especially stuff sent just in case it’s needed) put some or all the tools in the small airlock so if the crew needs something additional it can be quickly sent out without having to stop the EVA and bring everyone back in. Or if they use something once early on and don’t need it again, they can put it back inside through the small lock.

    Another way to do something like that is to have lockers located around a station, each with a set of common tools. The EVA crew goes out with the materials they’re expected to use, but don’t have to take along tools because on the way to the job site they’ll stop at the closest tool locker. If additional materials are needed or a different tool is required to improvise a fix (remember the toothbrush used for cleaning a hole with damaged threads?) one of the crew can go to the small airlock and quickly get it.

    Such things would make EVAs more efficient, either by taking less time or by being able to do more in the same time – if the planners don’t have to try and plan in advance for as many possibilities as they can think of.

  6. Though 3D printing would be most efficient, especially if the printer stays in LEO, I think that this technology is (currently) too complicated and prone to error. I guess that something inflatable or IKEA style would make more sense, though it sounds less fancy and innovative and therefore would get less attention and funding.

    But hey… I’m not specialized on mechanical stuff, nor space. However, there is a guy who apparently is and he gives a very interesting talk about how to design a spaceship. Unfortunately it’s German…

  7. SpaceX’s Falcon Heavy fearing is decidedly undersized for the LEO launch capacity of the rocket. They can very likely run a much larger fairing (It would require extensive rejiggering of the aerodynamics control program though) IF there was a market for it. For ease of manufacture and because there isn’t much demand for launching something that large they’ve decided to keep running the same fairing as F9, but if there was a large-ish demand for “oversize” capacity, I have no doubt they could fill that. with their existing launchers. Putting a more traditional second stage and fairing on the Super Heavy launcher is another alternative. Again there has to be enough demand to give them the incentive to build something like that.

    However, I see more future in modules like the Bigelow Aerospace BEAM or B330 that require less launch volume for the internal volume they offer, without requiring absolutely glitch free production/assembly in orbit.

  8. Has anyone ever considered using lasers to ‘drill’ down through the two miles of ice sitting atop Antarctica? One could employ the resulting tunnel to construct a hybrid space cannon using railgun and scramjet technology.

    Or what about a space pipeline? Essentially a long balloon filled with lighter than air fuel (H2 or CH4), 3D printed from one end until it reached LEO, at which point the other end would be opened and connected to a condenser to gather and compress the gas flowing from earth.

    1. I don’t know about lighter than air fuel. If you are filling a column up to, let’s say, 200 km altitude, the pressure at the bottom is going to be pretty high, and the density far higher than that of sea level air. Sorry, but I’m not going to do the math right now.

  9. Slightly off topic but why not use any spare cargo weight to sent lead or other shielding material so long flight vehicles can pick it up after launch. If the tesla that is speeding through space was a lead lump instead that could have been used to add to shielding on future craft the test would have worked and there would be another step to long flights?

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