Sen—History was made at approximately 9:28 pm UTC on 24 November 2014 when the first 3D printed piece of hardware was completed on the International Space Station, ushering in what is promised to be a new era of off-world manufacturing.
This is no small feat when you consider that the old era of off-world manufacturing largely comprised of jumper leads being jammed into the end of a toothbrush (to form a rudimentary wire brush), or the literal square-peg-in-round-hole scenario played out during Apollo 13.
The 3D printer, manufactured by US-based company Made In Space arrived at ISS onboard the SpaceX Dragon cargo ship on 23 September 2014.
Fittingly, the first piece of hardware to be made in space was designed as a spare part for the current printer; specifically it is an access panel which fits onto the 3D printer’s extruder plate. Although it is unlikely that the original panel will need to be replaced, this part serves a dual purpose. There is a replica of this part back on Earth, and after a couple of months on ISS the new part will be sent back down to NASA and the Made In Space headquarters, and will be compared with the original part to check that its space-born twin has been printed as predicted.
On 4 December Made In Space posted images on Twitter of an additional 3 items which have been constructed on ISS.
These new 3 pieces (pictured below) are designed as test items, to be returned back to Earth and measured for deformation and stress while under load. The results of these tests will also confirm that the “prints” are performing as expected when subjected to different applied loads (compression, tension and flex).
Image of three additional items constructed on the ISS by Made In Space. Image credit: Made In Space
3D Printing 101
3D printing is a type of additive manufacturing process which allows physical objects to be constructed layer by layer, additively. This is opposed to more traditional manufacturing techniques which are terms as subtractive manufacturing processes (due to the subtraction of material to achieve the final shape of the object). Subtractive processes involve drilling, turning, grinding, polishing, etc. Needless to say, subtractive processes are incredibly wasteful, with a large percentage of the original material disappearing in the form of metal chips.
Additive methods are significantly less wasteful, with almost all of the feedstock being used in the production of the finished part. No chips, no waste.
There are actually many different types of 3D printing process available, and they can be divided roughly into 3 groups depending on the source feedstock selected. These groups consist of liquid systems (stereolithography), powder systems (such as Selective Laser Sintering) and solid systems (such as Fused Deposition Modeling printers). The system currently installed on ISS is the latter type, which is abbreviated to FDM.
Made In Space selected the FDM process as the most viable technique for 3D printing in zero gravity as it seemed to be the process best suited to the environment, with the highest all-round benefits. Liquid systems such as stereolithography are fraught with problems ranging from behavior of fluids in microgravity to the sheer mass and volume of the feedstock required. Powder based systems are similarly tricky. Nobody wants titanium dust floating around the space station, and the power requirements for fusing metal together are far in excess of the power budget allowed for the experimental glove box where the current printer is located.
With these factors in play, Made In Space opted for FDM, which extrudes a thin filament of heated ABS plastic through a nozzle, creating a thin layer of material on the print bed. Additional layers are extruded on top of existing layers and are bonded to the preceding layer via a process known as “cold welding”.
Why 3D print in space?
In short, the 3D printer is going to allow astronauts the ability to manufacture end use items that are fit for purpose and actually resemble the schematics from which they are derived. This means that the space agencies can save on mass launched by sending only the raw feedstock, to be used if and when a new part is required.
A large percentage of parts flown up to the ISS on the various manned and cargo vessels are essentially spare parts, and a lot of the time these parts are not even used. They are sent up purely as a backup in case a part should fail, because when you are freefalling around planet Earth at orbital velocity it is better to have a part and not need it than to need a part and not have it.
NASA has concluded in studies that approximately 30% of these spare parts can actually be manufactured with an onboard 3D printer. This changes the paradigm significantly. No longer will mass budget be wasted on parts that may never even be needed. Instead, the feedstock can be sent up to the station and parts can be printed on demand.
Of course, the possibilities do not just end with spare parts. CubeSats and larger space structures can potentially be constructed in orbit, and because these systems will be manufactured in orbit and deployed directly from the ISS it means that in principle, the structures do not have to be designed to withstand the same forces as ground-launched systems. After all, they are not susceptible to the same g-loads and vibrations experienced during a rocket launch. Ultimately this could give rise to complex new geometries and strange new shapes within the satellite industry—geometries which are not dictated by the size and shape constraints of the launch vehicle’s payload fairing.
Made In Space engineer John Conley took time out from what has been a very exciting couple of weeks for the company, to chat with Sen about the technology and the company behind the new ISS printer.
Sen: What differences (if any) are you expecting to see between the new part and the replica, when your new part returns to Earth?
John Conley: It's been great to work with NASA to build and fly the 3D Printing in Zero Gravity Experiment so that we can find out what (if any) differences there are. It's called an experiment for a reason, so we'll have to wait for the results to know the extent and specificity of any differences. Prior to launching the printer, we did conduct parabolic flight campaigns to verify that our printing process results in prints that perform comparatively with those on the ground. We're excited either way—either we find out it's the same, which means we can bring all of humanity's experience from ground 3D printing to space, or it's different and we receive valuable data on those differences, which means clever people will find something unique in space to use to their advantage.
Sen: On Earth, FDM processes require support structures to prevent the overhangs on print jobs from sagging or collapsing due to gravity. How does the weightless environment affect the need for support structures?
JC: In some of our test prints with NASA, we'll be exploring that exact idea. We have some obvious advantages over ground-based printers here, of course, since gravity is the primary (though not the only) environmental factor that can affect overhang length. We're planning on looking into a variety of possible space effects to learn how to really work in the space environment. It's a little hard to wrap your head around at first, but there isn't really such a thing as an "overhang" in space since there's no directionality. If we can print in one direction, we expect to be able to print in all.
Sen: How much interaction does the current printer require from astronaut crews?
JC: We've had to work very hard to make this process as hands-off as possible. Astronaut time is a precious commodity in space, so we have to be able to use it most efficiently when we do have it and still leave time for our fellow payloads on board ISS. We designed the printer to be remotely operated from our ground station at our offices in Moffett Field, CA, so all we need for astronauts to do is to turn on the power and take the part out when it's complete. Our next printer, the Additive Manufacturing Facility, will be even more automated for greater commercial accessibility. We've actually had requests from the crew, though, to give them more access to the controls—they love operating the printer and want to run their own prints!
Sen: What is next for Made In Space? And how far ahead into the future are you looking in terms of projects? (e.g is there a 5 or 10 year plan for MIS?)
JC: We plan at several different time scales for the company. We're already working with NASA on a new project to build a plastic recycling facility so that we can chop up and reuse previously printed parts that aren't needed anymore. By making our own filament on orbit, we can reduce upmass that has to be launched from Earth. We think that's a big step in pushing forward our ability to "live off the land" in space, which reduces costs and increases safety and capability. That mentality informs our long-term plans, which focus on building the suite of technologies necessary for making humanity a species with more than one home. In the near term, we have some really exciting projects we're working on in our R&D lab, but we'll have to save those for a future interview. Stay tuned!
Sen: Great! Thanks for taking time to talk to Sen. Good luck with the future projects. I for one will be watching very closely indeed!
Made In Space are the first entity to accomplish this feat of manufacturing in orbit, but you can be sure that they won’t be the last. In fact, Made In Space are currently developing a second 3D printer (to be launched in 2015), which will be capable of printing a wider range of materials and will be commercially available to interested researchers.
Additionally, ESA are planning to send a European 3D printer to the ISS in 2015. Known as the POP3D (Portable Onboard printer), this version will be capable of printing with the PLA plastic filament, and will allow European researchers to conduct further experiments which further push the boundaries of off-world manufacturing knowledge.
And off-world manufacturing seemingly does not end with 3D printing. If the future resembles that predicted by certain asteroid mining companies then there will be a need to manufacture cast metal parts as well, and ESA are covering their bases in this field.
Also next year, ESA will fit four metal casting furnaces onto a Maxis sounding rocket to test the effects of weightlessness on the metal casting process. Indeed, 2015 is looking to be a very exciting time for those working in the field of off-world manufacture (myself included).
You can be sure that we will keep you updated with all of these awesome new developments as they happen.