At the moment there are no 3D printers in space, so you'd think there's no market for such things.
We disagree. It's possible that one of the biggest future markets for 3D printers will be beyond mother Earth, in space where the future will be built. By 3D printers.
The single, most important reason we think this is simply that it is fantastically expensive to loft finished items into space, becoming even more expensive the farther you want to go.
Imagine the cost of say, shipping a complete human habitat to Mars versus shipping a specialized 3D printer that could construct the majority of the structure from freely available onsite materials, then shipping only the remaining complex components for installation. This could significantly reduce the cost - and increase the probability of future space travel.
Where ever we require an installation, a 3D printer suitable for the job could reduce costs. Even better, the device could continue to operate, making potentially endless products available at terribly remote locations.
Who would need these specialized 3D printers? For now it may only be governmental institutions, such as NASA or ESA. But in the very near future, multiple commercial ventures are poised to make that giant leap to the beyond.
They will buy space 3D printers. They will build our off-planet infrastructure with them. They will create our new worlds with them - and new markets for 3D printing.