From 3D Printers to Self-Replicating Machines

I've seen the future. It looks like a microwave oven, but inside, a small robot arm is zipping away, making things. As I watched this working three-D printer on display at the main in BHV department store in Paris, I remembered seeing my first fax machine in the 1980s. Pre-Internet, duplicating a written page at a distance was amazing. From 2-d to 3-D is a huge jump, and we've made it. Now you can "print" a wide variety of things - coffee cups, toys, lamps, shoes, even guns! This past summer started their own 3-D printing store. But what's the next jump, the one that will make 3-D printing seem as quaint as a fax machine today? One obvious step - the one scientists and sci-fi writers are already working on - is self-replicating machines. Program in the right computing capabilities, and these could become machines that will evolve.

Why would we humans want to do that? Why create something that could potentially out-evolve us? The easy answer is space travel - according to author Will Mitchell. Mitchell is an aerospace engineer and the author of the science fiction novel Creations, set in 2040. I interviewed Mitchell about this not-so-distant future.

Question: Why do you think space travel will provide the impetus for building self-replicating machines?

Mitchell: Getting stuff into space is expensive. The distance to Low Earth Orbit is just two hundred miles, yet the cost of lifting material vertically upwards with nothing but rockets to propel it runs to thousands of dollars per kilogram. So if we're going to establish a wider, more permanent presence in space, without ferrying every bit of equipment, food and water from Earth, it will need to be self-sustaining, with the ability to exploit local resources with minimal resupply.

Space policy planners are aware of this, and are already thinking ahead. In October this year the White House Office of Science and Technology Policy started looking for ideas, on how "massless" space exploration can be performed. The aim is to find the smallest amount of hardware which can be launched into space (Moon, Mars or asteroids) which can then blossom into a self-sustaining mining and manufacturing infrastructure.

Some intriguing ideas are already being investigated: lunar construction using local materials (so-called lunar "regolith"), 3D printers as a versatile manufacturing tool (one has already been trialled on the International Space Station), and most interesting of all -- and the main subject of Creations -- self-replicating machines.

Question: Where did the idea for Self-replicating machines come from?
Mitchell: The idea has been around for decades. In 1980 though, NASA took a serious interest; in July of that year they spent two months coming up with concepts for self-replicating lunar factories, intended to strip-mine the entire surface of the Moon in a matter of years with an ever-increasing population of automated fabricators, starting from a single robotic "seed". Significantly, they found no fundamental obstacles to doing this. The technology is beyond us -- so far -- but the fact it's possible is beyond doubt.

Question: How did you extrapolate this idea on Creations?

Mitchell: The book is set in the year 2040, with lunar colonization well underway, and companies vying to find ways of exploiting the moon's minerals. One of those companies picks up where NASA's real-world research left off, and sets its sights on self-replicating machines.

The question posed by Creations is this: what if it went wrong? What if this exponentially growing swarm of autonomous machines stopped doing what their human controllers wanted? What if evolution took over, the familiar process of natural selection, ensuring that those machines which are best at surviving and reproducing, not necessarily the ones most useful to us, go on to create the next generation? What would that mean for the human race?

Question: Do you think this would be the outcome if this was attempted for real?

Mitchell: If someone built machines capable of copying themselves from raw materials, then left them alone long enough, eventually something we would recognise as evolution by natural selection would occur. The parallels between biological life and machine life (if you want to call it that) run very deep, and one of the main aims of Creations was to explore that comparison. Of course a real NASA-style replicator programme would not be left untended, and would be designed from the outset to remain under the control of the people who set it running. However the machines' designers in Creations are greedy and woefully negligent. If the programme was run the way they do it, the kind of carnage shown in the book could be a very likely outcome.

Question: Looking to the positives instead, what kind of benefits could this technology bring? And how far could this process go?

Mitchell: The Earth has finite resources, and has suffered multiple mass extinctions in the past. If we're not going to see the human race die out one day, we need to be a multi-planet civilisation. The places we could go however are very hostile to life -- airless Moons and rocks, with no shelter, no liquid water. But imagine being able to "seed" the Moon or the asteroid belt with self-replicating constructors, which as well as multiplying themselves could build things for us like pressurised habitats ready to move into, hundreds of thousands of square miles of habitable space spread throughout the solar system. The scale of it seems unthinkable right now, but exponential growth is the primary feature of replicating machines, and things that grow exponentially can do big things in short time spans.

Question: Do you think this kind of technology will be viable by 2040, the year Creations is set?

Mitchell: If people set their minds to it then I don't see why not. My job is in aerospace engineering, and I've worked on space-based projects in the past, and follow space exploration avidly. So everything in Creations from the lunar base, to the trips to and from space, even the suits they wear on EVA, was as plausible as I could make it using my own knowledge of aerospace technology. That 1980 NASA study paved the way for a lot of subsequent research, which people are building on right now, so in the next two to three decades maybe this will become a reality.

Will Mitchell has been writing Science Fiction and Horror since the late 1990s, with stories appearing in various short fiction magazines on both sides of the Atlantic. He was recently a winner in the Writers of the Future contest. By day he is an aerospace engineer, and lives in East Sussex. His first novel, Creations, is available at,