WHY THIS MATTERS IN BRIEF
- Turning an asteroid into a spacecraft sounds easy, but it isn’t, however, thanks to 3D printing and some brainy experts we could see the first asteroid spacecraft appear in the 2030’s
The concept of mining things in space, whether it’s mining the Moon for platinum or Helium-3 for tomorrow’s nuclear fusion reactors, or asteroids, has been gathering pace recently with announcements from a host of countries, such as Japan, as well as private space exploration companies like Moon Express, that they’re moving ahead with their quests.
But when it comes to mining, given how expensive it is to lift anything into space from the surface of the Earth, the future of efficient and affordable space exploration and travel may be dependent on using the resources that are already up there. Space may seem big and empty but there’s a limitless amount of resources up there floating around in the form of asteroids, comets and planets but the trick is going to be rounding up some of these objects, such as asteroids, and bringing them somewhere they can be mined without having to spend too much time and effort to chase them, or transport resources back from their surface.
Made In Space is a company that develops technology to, well you might have guessed already, make stuff in space. For example, they’ve got 3D printers aboard the International Space Station (ISS) that print tools, and even human hearts, and they’ve experimented with turning simulated regolith, that’s moon dust to you and I, into a material that can be 3D printed into more useful things. now, with funding from NASA’s Innovative Advanced Concept Program, they’ve been exploring a wild idea…
Rather than travelling backwards and forwards to mine asteroids why not turn the asteroids into small spacecraft and have them come to them instead? And as for the question of how do they think they’ll accomplish that particular magic trick? Well, their answer is Project RAMA, short for Reconstituting Asteroids into Mechanical Automata, a small spacecraft that can deposit a small 3D printing kit onto an asteroid where it will self assemble, and print everything it needs – from computers, guidance systems, gyros, engines and rocket fuel – to turn the asteroid into a self-assembled, self-contained, self-propelled, fully autonomous spacecraft. After all, all you really need to do is stick a guidance system and an engine onto an asteroid and there you have it. Then once RAMA has “caught” and transformed one asteroid it would move onto the next.
But of course – it’s not that easy, and the idea of grabbing asteroids and bringing them back to the Earth, or at least the Moon, to harvest their resources isn’t new. NASA announced a few years ago that by 2025 they want to travel to an asteroid, mine part of it and bring the samples back to Earth for analysis.
“One of the big questions is, how do you take today’s most intricate machines and make them replicate themselves? That seems really hard – how do you replicate electronics and processing units and so on. And that’s when we had this concept that there are types of machines that could potentially be easy to self-replicate, and those would be very basic, analog type devices. The problem is if you have a small mechanical machine, it’s not very useful. But what if the machine itself was the size of an asteroid? What could you do with a mechanical machine that large?” said Jason Dunn, co-founder and CTO of Made In Space.
“Right now, we don’t have the technology to 3D print, say, a digital guidance computer here on Earth. We certainly aren’t ready to do it using only the kind of materials that you’d find on an asteroid. What Made in Space has realized, though, is that it’s not necessary to rely on digital electronics if you have an enormous amount of raw material and no constraints on volume or mass. Instead, you can build a purely mechanical analog computer, using things like gears and rods and levers linked by chain belts – perhaps with 3D printed mechanical punchcards for data storage and mission execution instructions. This is all very old technology, but it’s also well understood, reliable, and easy to build from simple parts,” he said.
With computing taken care of, what about everything else you’d need for a spacecraft? Well, you could 3D print giant flywheel gyros for guidance and stabilization. For energy to run things, you could 3D print springs and preload them with the seed craft, or you could 3D print tanks for storing volatiles, then heat them up using 3D printed solar concentrators to generate mechanical power through the release of pressure. The engines are just as simple – catapults, like, the kind that used to throw rocks at castles, medieval style.
Thanks to the laws of acceleration, throwing chunks of itself in one direction with catapult like mass drivers, the asteroid could accelerate itself in the other direction. This is only about 10% as efficient as a chemical rocket engine, but the propellant is free, as long as you don’t mind your spacecraft eating itself. Made in Space has estimated that it might take throwing away something on the order of 60 percent of a candidate near-Earth asteroid’s mass in order to bring it in for mining, and that sounds like a lot. But another way to look at it, though, is that if you’re clever enough to throw away only the mass that you don’t care about – leaving metals and volatiles behind – the asteroid could arrive at the mining station “pre-refined.”
The hardest part of all of this is going to be designing the seed craft. They’ll have to be incredibly capable, with the ability to not just 3D print things using whatever materials it finds, but also to 3D print more analog 3D printers to speed up the process. And fortunately, we know how to do this, too. You can imagine the seed craft setting down on an asteroid, scooping up some regolith, and then printing out an analog 3D printer pre-programmed for self-replication. Eventually, it would switch over to printing gears and punchcards and catapult parts, and when it had everything it needed, the seed craft would become the assembler. Once everything is put together, the seed craft would do the equivalent of flipping the “on” switch, then leave the asteroid to pilot itself back to Earth.
As fantastical as it sounds, most of the fundamental technologies to make Project RAMA happen already exist, which is probably why NASA is funding it. The goal of Phase 1, which will begin this year is to understand how the seed craft would have to work, defining requirements, and building a technological roadmap. If everything goes perfectly, a seed craft could potentially be sent to a near-Earth asteroid in the early 2030s.