WASHINGTON — Even though 3-D printing is only just ramping up for mainstream applications down here on Earth, it's already out of this world.
Astronauts are printing up a storm on the International Space Station (ISS) and if the next phases of NASA's additive manufacturing project go according to plan, they will soon be doing a lot more than banging out wrenches and spare parts in space.
The first object to be 3-D printed in space was a spare part for the printer itself: an extruder casing, emblazoned with the name of the printer's manufacturer, Made In Space, and the NASA logo. It was quickly followed by a side plate for the extruder casing.
For the first print, “it needed to be something meaningful, something we're getting test data from,” said Niki Werkheiser, NASA's 3-D print project manager. “A lot of these things probably look kind of boring to the layman. But that's the first time we've heated and extruded plastic in space. Even if didn't work at all and it had printed a blob, which we know it didn't, there would have been no other way that we could have possibly learned that without flying it on the space station. The space station is the only laboratory platform in microgravity that's available.”
Since that first successful print on Nov. 24, ISS astronauts have moved on to bigger and better — and more recognizable — items, including a ratchet wrench. The wrench's files were designed, approved and sent to space in less than a week and printed in about four hours, truly testing NASA's on-demand 3-D printing capabilities. And putting a tool in the hands of the astronauts that was originally shipped to space as humble ABS 7006 filament.
The first phase of the 3-D print project, a $1.4 million Small Business Innovation Research (SBIR) contract with California-based Made In Space, is testing the feasibility of astronauts manufacturing their own parts and tools in microgravity.
Taking additive manufacturing to space will eventually minimize taking parts and tools from Earth to space — which comes with a $10,000 per kilogram of launch weight price tag, among other issues — and increase ISS's self sufficiency. The test coupons, parts and tools from this phase will eventually head back to Earth to be compared with the same objects printed by an identical printer on the ground.
“We're going to bring all of the engineering samples back for comparison to the ground controls. We are using video for initial analysis, as well. We are seeing that with the parts with the larger surface areas, removal has been challenging. What we've got to figure out is if that's really an aspect of microgravity. We do see that on the ground, it just seems to be happening with more frequency on orbit,” Werkheiser said, noting that while the printers were built to be identical, only one has been through a launch and a microgravity calibration. “Adhesion is definitely one of our questions.”
In addition to comparing printing process notes, the parts actually made in space will be tested for tensile strength, torque and flexibility. The results will help Made In Space to perfect the next generation of their microgravity 3-D printer, which expected to ship to ISS early this year.
But there is much more to the next phase of the project than sending another printer to space. Already going by the acronym AMF for “additive manufacturing facility,” the next generation of 3-D printer for ISS will be commercial printer by Made In Space with the lessons learned baked in and a whole planet of users.
“This will be their printer and NASA will be one of their customers,” Werkheiser said, describing something of a national lab in space. “The other entities, universities, industry, anyone on the ground, will be able to 3-D print on the space station.”
Made In Space's Grant Lowery describes the AMF as “a permanent machine shop in space.
“Obviously it's there for the astronauts, and for experimentation. But it will also be commercially available, owned by Made in Space,” he said. “Anyone conducting experiments on ISS can get in the queue.”
In addition to being larger than the initial microwave-sized 3-D printer, the AMF will have multi-material capabilities, Werkheiser said, most likely starting with PEEK and Ultem because of the plastics' strength, good safety ratings and excellent thermal properties.
“Ultem is used for making a lot of the EVA [extravehicular activity, or spacewalk] tools already,” she said. “So it might not be a known quality for printing in space, yet, but it works well for us up there already.”