Plastic that is out of this world

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.”

Other projects

A bigger, badder printer to go where no printer has gone before isn't all Made In Space has been working on for NASA. In early 2014, the government awarded two Phase I SBIR contracts of $125,000 each, one to Made In Space and the other to Tethers Unlimited Inc. in Bothell, Wash., to develop a recycler that will take 3-D printed plastic parts or other plastics and recycle them back into useable feedstock. Werkheiser said the plan is to fly a working recycling technology demonstrator in 2016.

“Phase I SBIR is usually a study, and don't usually get hardware. But both companies have already built the recyclers and recycled into filament with different materials on the ground,” she said. “The technologies are very different, so we may end up flying both of them.”

The plan would be the ultimate in sustainability: taking launch packing material like foam, film bags and Bubble Wrap and turning it into usable feedstock or using 3-D printed feedstock, minimizing resupply needs.

Lowery and Made In Space are tight-lipped on specifics for their ABS recycling system, R3-DO, there is no shortage of enthusiasm.

“It's definitely a move towards optimization and better use of resources,” he said. “If 3-D printers become the standard in space instead of redundancy, combined with recycling, it could take sustainability in space and deeper exploration so much closer to reality.”

Tethers Unlimited has already dubbed its recycling-in-space effort Positrusion, and is envisioning terrestrial applications as well.

“The proposed effort will develop a filament extruding machine that uses a process called Positrusion that is designed from the ground up for optimally producing small batches of positively controlled round filament directly out of arbitrarily shaped scraps of ABS plastic, while meeting requirements for operation on the ISS. The machine will accept miscellaneous ABS parts, it will dry and de-gas the input material before melting and extruding it through a die, and the cross-sectional dimensions and feed-rate of the cooling extrudate will be tightly controlled in a continuous analog of closed-die molding,” the company wrote in its proposal last year.

“The Positrusion process would not be suited for high through-put industrial purposes, but it will be marketable to a large portion of the growing population of household and workplace 3-D printer users to enable individuals to efficiently practice a self-sustaining 3-D printer material cycle.”

While some plastics problems here on Earth, like closed-loop manufacturing, might have their answers among the stars, the biggest questions for 3-D printing is space in future phases of the NASA/Made In Space project will be exactly the opposite of what is faced by designers down here.

On the International Space Station, there is no up or down, all four walls are used.

“What if you print in all four directions, to four print trays? Could microgravity eliminate the overhand and sag we get printing in gravity?” Werkheiser said. “It's fun to start thinking about the type of things we could design in microgravity that we can't do on the ground.”

But it is a mentality shift for designers, she said, moving out of what has to be added and into what you don't have to design for.

“We are very interested in, as much as the technology, developing that community of designers and developers,” she said.

NASA is making available to the public CAD files for its designed-for-space items so anyone on the ground can 3-D print them as well.

“I don't think we will revolutionize the whole concept of 3-D printing but in terms of making it even more applicable for high-optimization, repeatable technological advancement, I think we are helping with that, without a doubt,” Werkheiser said.

Made In Space is taking the future of space-ready plastics design very seriously, Lowery said, and is essentially issuing a challenge to the current and future plastics industry, and beyond.

“We're delivering a platform that's never existed before, taking CAD software to a place it's never been, and opening access to that capability,” he said. “Now that we have this machine shop in space, I want to see people start to grow the industry with us. We're handing out the keys, let's run with them. Figure out what's possible.”