A decade ago the first 3D printer to go to space was sent to the International Space Station. It proved to be so useful, more, bigger printers soon followed. Within a few years there was a veritable factory in space, churning out all manner of spare parts and items necessary for the maintenance of the ISS.

Then came the realization that it was much more efficient to send up printing materials by SpaceX courier rockets, than to build giant spacecraft and space hotels here on earth, and expend enormous amounts of fuel to launch them out of the atmosphere. The maximum diameter of the rocket payload was always a constraining factor, when designing structures destined for space.

But when the space modules are manufactured in weightless conditions by 3D-printing composite panels, huge boxy habitable structures can be easily assembled by astronauts and robots, making a roomy space hotel a feasible project.

Now they’re building the gigantic mothership that will be needed to take 200 colonists to Mars. Only with 3D printing in space can this even be considered. The final product will resemble a city apartment block rather than a spaceship, and will have the aerodynamics of a brick. But that’s OK, because it will never have to travel through the atmosphere, only the vast emptiness of space.

The greenies are unhappy with this development, as the base material is 80% thermoplastic: “We’ve filled the oceans with plastic pollution, and now you want to pollute space with plastic too!”