Australia's Made a House-Printing Robot—And of Course It's a Spider

If you haven’t been following international news too closely, you might not be aware that our friends down-under have a massive housing crisis. Then again, who doesn’t? However, what makes the Australian story a little different from the rest of the world is how one company aims to solve the issue—spiders.

That is, a huge robot spider, which instead of spinning a web, extrudes building material to build houses. It’s a little ironic, because the one thing you’d think the Aussies don’t need more of are spiders, but they do need houses. So maybe it will all work out in the end.

Meet Charlotte: The Spider That Prints Houses

Yes, “Charlotte” as in Charlotte’s Web. Very original, Bruce. Full marks, mate. Cheesy name aside, this bot is an evolution of the 3D printing robots we saw about a decade ago. Most of which got around on treads, rather than legs. In fact, while doing zero research, I’m going to go out on a limb and say basically none of them walked!

Charlotte the robot being worked on by a team of technicians.

I do take some issue with Charlotte being referred to as a “spider” sporting only six legs, but as an avowed Ghost in the Shell fan, I’ll let the loose and fast leg count slide. Before we go any further, you should know that Charlotte is effectively a research prototype unveiled by Crest Robotics at the 76th International Astronautical Congress (IAC) in Sydney. That’s Sydney the city, and not Sydney your author, just to be clear.

You might notice from the name that this congress is all about space stuff, and not building affordable housing for people on Earth, but we’ll get to that.

How the Spider-Bot Works

Charlotte is a semi-autonomous hexapod robot. It uses “additive” 3D printing technology (pretty much like most home 3D printers) where you build up structures by laying down layers of material. What makes Charlotte special is that unlike most 3D printing solutions for making houses, the robot can move around freely and position itself as needed. Whereas systems that are already making houses that people live in work like a giant version of your home 3D printer, with a frame and rails set up over the build site.

There’s a lot more to it than that though. Charlotte uses Earthbuilt construction materials, making it an eco-friendly solution. The robot will build the walls from local materials on the site like clay, gravel, and sand or certain types of prepared waste. According to Earthbuilt:

A builder uploads plans to Charlotte™, who gets to work immediately, skipping around the site, building as it goes with earth from the site or certified waste from nearby. It does this accurately, according to the digital plans, stopping only for plumbers, electricians and carpenters to come in and do their bit.

Because Charlotte integrates mixing, compaction, extrusion, and movement into one process, it eliminates many of the intermediate steps and carbon overhead seen in conventional construction. The claims about Charlotte are pretty wild, with a single Charlotte eventually meant to do the work of 100 bricklayers. Completing the basic structure of a roughly 2000 square foot home in just 24 hours.

Remember that Charlotte is designed to do all of this without cement, firing, or brick manufacturing. So you can bypass huge parts of the industrial process involved in building, and use local materials without having to transport anything.

Why a Spider? The Design Logic

Now that you know what Charlotte is meant to do, it should be fairly obvious why the designers went with this spider-like design, but it’s still worth unpacking.

First, Charlotte has to move across uneven terrain, the sorts of places where there’s not enough room for a wheeled system. Second, Charlotte needs the ability to step over things and straddle walls to lay down more layers of material. Third, a robot of this design is foldable and compact. Finally, it integrates mobility and printing into one system. That’s a big cost, time, and energy advantage.

From Earth to the Moon

A CG representation of Charlotte the robot building a structure on the Moon's surface.

So, remember when I mentioned Charlotte was unveiled at a space congress? Well, if you think about it, the way Charlotte has been designed means it would be perfect for, as an example, building structures on the Moon. You could send a bunch of Charlottes out, and they’ll use the existing lunar regolith to make Moon base structures. The only thing you have to bring with you to the Moon, or Mars, is Charlotte. All the other materials you need are on-site, waiting for you.

Promise and Reality

Charlotte sounds like just the sort of sci-fi construction robot I’ve been dreaming of, but before we all get too excited, we have to remember this is a prototype. There’s a long road ahead before the Australian landscape—or the Moon—is littered with the hustle and bustle of mechanical spiders building stuff.

Apart from getting the technology itself to work reliably, there are plenty of regulatory hurdles to get through. Not to mention questions about the long-term viability of the building materials in use here. It’s also not clear if or when this construction method will be cheaper or more scalable than existing building solutions, including rapid 3D printed homes using other methods. Personally, I wish Charlotte all the best, and maybe one day I’ll live in a house spun by it, filled with other robots to wait on me hand and foot. Hey, a guy can dream!