The 3D printing of Lunar Base Shackelton.

[Aethon]

Very interesting video I hope will inspire a stimulating discussion.

Bonus informative/eyecandy video.

[Mazon Del]

NASA has been working on similar technology for a while (not quite sure how long). I believe their intended printer has 8 long spindly legs with wheels on the end. This lets it drive around however it wants, but it can also 'walk' over obstacles (such as the object it is building) as needed. The center of this spider bot contains the 'printing' system. The top has a hopper for moon regolith and the original plan (may not be what the current plan is) was to actually just straight up melt the regolith and deposit it much like a plastic extrusion printer does today. Now, it may have shifted (or always been, I am admittedly a little sketchy on the details) from such an energy intensive (but quick) process, to one more like current metal printing where you drop down a layer of dust, then zap it with a laser to melt just what you wanted to melt, and only a little bit of it.

[kerbiloid]

1. Get a pit.

2. Put habitat downwards.

3. Bury a pit with a bulldozer.

...

4. PROFIT!

No 3d-printers involved, nothing to melt.

[prophet_01]

This is a lot more leightweight, than an underground base. It's not like the space agencies budget is going to rise... I doubt this is something that will be realised soon though. From my point of view a long duration mission on the moon is not going to happen for a scientiffic reason, the costs are still to high. And tbh I don't see a comercial justification The only more or less reasonable thing to do on the moon might be producing and delivering fuel to LEO, which could be cheaper in theory (but remember, in theory we would still have space shuttles ). I doubt that there is enough profit in this to make anyone risk the investment.

The pricy partd here are the resupply of consumables and the crew rotation. But I still think this is a good way toward a realistic mission profile (from a practical and finacial point).

The mVastly reduced cost per kg payload to orbit would be needed to make that happen.

However it's a nice presentation. And this sounds like something that will be part of a number of future concepts, which as always won't get the funding sry for not being optimistic

[kerbiloid]

This is a lot more leightweight, than an underground base.

Why? The "roof" square is the same, the ground layer thickness is the same.

So, the ground weight just above the habitat is the same.

Of course, you would shovel 2..3 times more ground aside of the habitat - just to fill the whole pit.

But instead you don't need to melt tons of metal oxydes (many megajoules btw) and then to flush them through a pipette.

I.e. bank 20 tons with a primitive bulldozer which is useful anyway  or to dig, melt, filter, push 10 t and need 3d-printers and a reactor.

[Tommygun]

3D printing can have its place in construction, but I don't think this is it. This just adds complexity that's not needed.

You will have to lunch all the printing materials up to the Moon when just burying it works.

If you want to make an actual building with it then this could be useful, but don't waist it on burying a building you bring with you.

I still prefer the simpler idea of using solar furnaces to melt regolith into blocks that you build with and then spray the interior with an airtight seal.

You need to ship less material to the Moon with this technique. The machinery is also simpler.

[Streetwind]

1. Get a pit.

2. Put habitat downwards.

3. Bury a pit with a bulldozer.

...

4. PROFIT!

No 3d-printers involved, nothing to melt.

What if you cannot "get a pit"? Sending an excavator (which needs to be heavy) is no cheaper than sending a machine capable of building walls (which can be lightweight), and excavating in 1/6th gravity is a completely different process than digging a hole on Earth (especially if the weight of your excavator is constrained by what you can send). Meanwhile wall-building is pretty much the same and can be tested down here.

Besides, there are other reasons why you'd want a proper wall. For example, you can pre-plan and control exactly how much load is placed against any given point of the habitat walls. Just heaping regolith on top while sitting in a random hole will not let you do this. The 3D printing process also stabilizes and hardens the wall beyond what a mere layer of loose regolith would offer. Later extensions of the habitat become much easier.

[kerbiloid]

What if you cannot "get a pit"?

Find, blow up or excavate.

Bulldozer/excavator is a primitive, hard and rusty machine, and you anyway need it building a serious moon base, not just a tent camp  at least to level the ground or to make roads.

Melting metal oxydes to make 3d-inks requires a powerful energy source, and 3d-printers are delicate equipment.

So, sending a bulldozer/excavator is much easier than sending a bulldozer/excavator and several self-propelled 3d-printers. Also you don't need to melt ground just to make a layer of inert material. You need only shovel it onto the roof and cover with a nice plastic sponsors' billboard.

1/6 gravity btw makes all the process much easier than on Earth because potential energy is 6 times less.

Besides, there are other reasons why you'd want a proper wall.

Wall itself is even more proper! You have the same solid metal capsule wall and miles of ground in any direction except the roof.

For example, you can pre-plan and control exactly how much load is placed against any given point of the habitat walls.

No need to do exactly. You would put just about a meter of ground as an anti-radiation and anti-meteorites protection.

And there's nothing to pre-plan when you make an outpost. Any plans will change many times and anyway you will need heavy machinery. Why not just to send one of bulldozers a bit earlier.

[Streetwind]

1/6 gravity btw makes all the process much easier than on Earth because potential energy is 6 times less.

That is the case with lifting things, but for excavating it gets in the way. An excavator must press its digging shovel into the ground, and it does so by means of leveraging its own mass as a counterweight. If its weight is greatly reduced due to lower gravity, the ability to penetrate the ground is also greatly reduced. Now combine that with the fact that an excavator launched into space would have to be small and leightweight by default, and you could possibly get to the point where the excavator would push itself off the ground before it can overcome the hardness of said ground. It would wobble about as it scrapes at the rock in futility instead of digging a hole. Fun to watch for the astronauts, perhaps, but ineffective at building them a shelter

I'm sure this problem can be overcome, for example by some form of anchoring the excavator to the ground while it digs, but it's by far not as simple as you think it is.

[kerbiloid]

Just some dynamite and then something like this:

Use excavated ground as a ballast if needed.

Then roll down modules and bury them.

BTW: all buried habitats would look absolutely similar  like a low ground hill, and KSP modders could use one model and texture for all of them.

[Guest]

Digging holes on Moon is easy: just deorbit said bulldozer without any landing engines, and you will have nice crater, may be even metal-lined inside.

[kerbiloid]

Digging holes on Moon is easy: just deorbit said bulldozer without any landing engines, and you will have nice crater, may be even metal-lined inside.

With Kerbals you don't need even this. Just use pits left by the previous Kerbals.

[dansmithers]

On topic, I think many people believe that 3d printing is somehow "better" or "more efficient" than existing methods of building things. For the most part, its not,and I'm really starting to get sick of all the hype.

There is a reason we do not assemble everything from Lego blocks- it's inefficent, slower, and the materials are specialized. The same arguments stand against using 3d printing in any industrial setting.

[sgt_flyer]

3d printing is useful in some cases, but not all.

- rapid prototyping (no need to build expensive specialized moulds to create a part - if you need a simple part copied a huge amount of time, an injection mould is waay better)

- create complex shapes which would otherwise require various simpler parts to be assembled together.

- when you need to create something different each time you use the machine. (Like the 3d printer they sent to ISS - useful if they need to make a special shape to fix a problem - no need to have a stockpile of parts, just build what you need when you need it from the 3d printing material)

- in case of space exploration, reuse avaible resources (here, Regolith) to not have to bring the building materials with you to make variable shapes. (A specialised machine could build only 1 type of house for example, while an human can adapt and make different models of houses)

Now, of course, we can hope we'll see faster and more effective 3d printing techniques in the future which could challenge specialized techniques - but we are not there yet.

Edited November 19, 2014 by sgt_flyer

[Mazon Del]

On topic, I think many people believe that 3d printing is somehow "better" or "more efficient" than existing methods of building things. For the most part, its not,and I'm really starting to get sick of all the hype.

There is a reason we do not assemble everything from Lego blocks- it's inefficent, slower, and the materials are specialized. The same arguments stand against using 3d printing in any industrial setting.

Actually this is far incorrect. There have been experiments done in 3D printing houses using a combination of concrete for walls/floors and metal supports for overhangs. The projections from the half scale prototypes state that you could have a two story house meant for a family of four printed out in roughly 20 hours and a full neighborhood inside of a week if you have a good alignment between your gantry rails and the road in question. The best thing about the system is that generally speaking houses of wildly different designs, but of the same volume, take almost about the same time to print. No specialized materials are needed for any given home printed by the system. The concrete used is one of the super fast curing (sp?) types which contrary to popular opinion really isn't all that much more expensive then standard foundation concrete. You go to the same plant, you just request a different mix. They WILL have the necessary ingredients because it is mostly a question of ratios rather than adding or subtracting something special.

The professor developing the system has been going about it slowly (he has a day job as a professor after all) over the last 5 or so years. The main impediment he sees to the adoption of the system is simply the fact that we don't build enough homes in the US to really justify needing this system. Honestly though, I think he is mainly just working on the version that can build skyscrapers.

Edited November 19, 2014 by Mazon Del

[magico13]

Why don't we just build a base in one of the Moon's caves? Then you've got overhead support already and since they're in giant pits you've also got coverage on the sides. I suppose there is concern for cave-ins, but I figured I'd at least mention it.

http://www.space.com/26592-manned-moon-exploration-lunar-pits.html

[Streetwind]

Depends on whether the spot where you want to build your base has caves. Also, getting power and sunlight (for quality of life) into these caves is more difficult than it is when using aboveground habitation shielded by a layer of regolith.

The caves also limit the volume, shape, extensibility, capabilities, accessibility etc. of your base.

It's one possible option, and one that will most likely be used, but it won't be the only option.

[Rakaydos]

Besides, the problem with both caves and pits, is navigating the stairs in a spacesuit whenever you go in or out.

[Mazon Del]

The airlock probably would be arranged for a minimum of stair climbing in a suit. Those pits would certainly be nice to use.

Of course, lets all take a moment to remember that we shouldn't use non-radioactive nuclear weapons to create spaces under the moons surface to build a habitat on. Unless you want Morlocks. Because that's how you get Morlocks.

[Idobox]

Unless you want Morlocks. Because that's how you get Morlocks.

For some reason, I'm picturing Sterling Archer saying this sentence.

[kerbiloid]

Why don't we just build a base in one of the Moon's caves

Why don'wet continue living in natural caves, building instead city caves?

Because they are rare, have a random non-useful structure and are geologically unpredictable.

Also, getting power and sunlight (for quality of life) into these caves

There is no atmosphere btw.

Do you want you room frozen/heated -100..+100 C every day  as lunar surface?

So, anyway they will live with artificial illumination and watch the nature through webcams  whether over the surface or under.

(Btw: what to look for? No birds, no trees, no clouds. You can just use a picture instead of webcam  no movement around except rovers.)

Power is anyway provided by a cable from an energy plant placed anywhere.

Besides, the problem with both caves and pits, is navigating the stairs in a spacesuit whenever you go in or out.

Airlock/door on the surface, downstairs, Vault 101, as usually.

Because that's how you get Morlocks.

Urban office, artificial light, water from cooler, air from conditioner, sunblinded windows...

Most of people wouldn't even notice any difference  except low gravity. So, no problem.

[prophet_01]

Urban office, artificial light, water from cooler, air from conditioner, sunblinded windows...

Most of people wouldn't even notice any difference  except low gravity. So, no problem.

as a guy working indeed in an office, I gotta admit you aren't that wrong. Since we have winter right now I go to work when the sun isn't up yet and go home when it's dark already but I miss the sun nevertheless... It's kinda like a placebo with screens. People are like that. If you know it's a screen it's not that nice anymore. although it may help to make the little room you live in look bigger

[dansmithers]

Actually this is far incorrect. There have been experiments done in 3D printing houses using a combination of concrete for walls/floors and metal supports for overhangs. The projections from the half scale prototypes state that you could have a two story house meant for a family of four printed out in roughly 20 hours and a full neighborhood inside of a week if you have a good alignment between your gantry rails and the road in question. The best thing about the system is that generally speaking houses of wildly different designs, but of the same volume, take almost about the same time to print. No specialized materials are needed for any given home printed by the system. The concrete used is one of the super fast curing (sp?) types which contrary to popular opinion really isn't all that much more expensive then standard foundation concrete. You go to the same plant, you just request a different mix. They WILL have the necessary ingredients because it is mostly a question of ratios rather than adding or subtracting something special.

I have seen this project as well. How much do you think one of those printers costs? Not to mention the fact that any house printed this way still needs to be insulated, roofed, floored, have windows and doors installed, plumbed, and wired.

I could build a wood-frame shack in 20 hours for pennies on the dollar.

EDIT: I understand the point of using 3D printing as we use it today, I just cannot see any firm using it when humans and and tools are cheaper.

Edited November 20, 2014 by dansmithers

[Mazon Del]

The printer itself? Frankly not a whole lot. Most of its existence is just the metal truss structure, very cheap. Sure you have the gantry motors, industry grade with precision position systems, expensive but not obsurdly so. The horizontal traverse, again industrial grade with precision positioning systems. The Z-height can be done through many ways, none terribly expensive. The extruder will be a little different if only because its a somewhat non-standard system. But in general there isn't anything super expensive in there either. I build 3D printers as a hobby and have been looking into the possibility of building one of these mega printers for a while. They are costly for a single person, but for a business they really are nothing special. Think of a mobile truck mounted crane, that is roughly how expensive one of these costs.

Insulation? Not at all. Your walls are a foot thick cement box filled with sand. Perfect insulation, super cheap, AND it helps protect your home from things like tornadoes and the like.

For the flooring, sure you need to add some tilework, woodwork, etc. This is a trivial aspect of home construction, literally a part that the owner can do themselves if they want. Excepting for very fancy or specialized work, this has VERY little bearing on the final cost of a home in terms of the construction cost.

Roofing? I somewhat presume you are speaking of the outdoor roof as any indoor ceiling is basically covered by the same description of flooring. This part gets into quite an interesting debate honestly. Considering that your standard slant-roof is somewhat unnecessary given these construction methods, the effort is minimized. Still want a slant roof? More costly because more material, but at the end of the day you can save money because the roofing will not need to be replaced as often. Effectively ever really.

Plumbing and electrical in some ways is easier, in most other respects is unchanged. The walls would be designed for ease of adding in the pipes and wires. About the only real drawback to this system is that it ends up being inflexible. IE: You cannot easily add a new power box to a wall unless you designed all the walls to have the requisite pipe/wire channels. Which there is no additional cost to do.

The vast majority of the cost in building a home is NOT materials, it is the fact that you need to pay dozens of laborers for 6 months to construct it. There is a company that every year constructs a house in under like 3 hours as a promo-gimic. The cost comes out roughly the same because they hire 20 times as many workers, but they only hire them for half a day. Their models state that it really only ends up being the same because they don't do it all the time. If they did, then the workers would adjust their costs upwards.

Kerbiloid: My comment about the morlocks is not people growing 'cave adapted' as Dwarf Fortress would call it. I was referencing the movie "Time Machine". SPOILERS: He jumps to like 2050 and they have this grand plan of using non-radioactive nukes to blow a large chamber beneath the surface of the moon, which will then become the space they build a colony in. Jump forward a year or two....oops...shattered the moon. Now everybody has to live in underground shelters, etc.

Edited November 20, 2014 by Mazon Del

[Idobox]

I have seen this project as well. How much do you think one of those printers costs? Not to mention the fact that any house printed this way still needs to be insulated, roofed, floored, have windows and doors installed, plumbed, and wired.

I could build a wood-frame shack in 20 hours for pennies on the dollar.

EDIT: I understand the point of using 3D printing as we use it today, I just cannot see any firm using it when humans and and tools are cheaper.

You're talking of building houses out of wood, which is pretty done only in North America nowadays, the rest of the world preferring concrete or bricks.

Typical cheap houses are made of cement blocks or prefabricated cement walls. The quality is not very good, insulation requires additional materials, and you end with square boxes. A concrete printer would make solid concrete walls (long lasting) with no restriction in shape, with very little human work. It can make walls with lots of empty cells for insulation, prepare ways for cables and pipes, do stairs, domes, pizza ovens and all sorts of wacky shapes with no additional costs.

The thing will probably not be very cost effective for single houses for a long time, but will be a great tool if you want to build 50 or 60 houses in the same place. I can also imagine applications beyond houses, like industrial or military structures.

And remember, once you have the machine, it costs next to nothing compared to human workers.