The Space for 3D Printing

It’s hard to go a week right now without catching a major news story about the space industry. And while I wasn’t around for the original space race, I can’t imagine there has been a time as exciting for space nerds like me since those early days. Need a recap?

• SpaceX put the first fully civilian crew into orbit, is delivering astronauts to the space station and rapidly pushing down the path to Mars.
• Virgin Galactic and Blue Origin have taken their first paying passengers to space.
• Lockheed Martin’s Orion capsule will soon return astronauts to the Moon
• Companies like Amazon, OneWeb, and SpaceX (again) are building massive constellations of small satellites.
• There is now a whole new industry of small launch vehicles from the likes of Astra, Launcher, RocketLabs, and Relativity.

From my vantage point though, a common and exciting thread running through these stories is the industrialized use of 3D printing for space vehicles.?Sometimes 3D printing’s role is prominent, such as Relativity Space creating custom metal 3D printers for their mission to produce 3D printed rockets.?Other times, it’s more subtle, like seeing a Stratasys F900 3D printer in the factory floor background of Blue Origin’s video on producing face shields for the pandemic response.?

I’ll let you in on a secret: Regardless of the extent to which they discuss it, nearly every new launch vehicle and satellite now flies with 3D printed parts on board, in addition to using additive technology in the development stage and manufacturing process.

Why??Think about the 2 Vs: Volume and Value of Weight.

Volume

Even with the massive proliferation of rockets and satellites we’re seeing right now, the space industry is low-volume compared to nearly any other manufacturing segment.?Low volume is expensive because costs come down in mass production as a result of amortizing tooling, automation, and set up costs across hundreds of thousands or millions of parts.?But if you are building one rocket a month, or even a hundred small satellites a month, the volumes don’t lend themselves to economies of scale. That makes manufacturing methods like injection molding largely uneconomical. ?In contrast, additive manufacturing of flight parts is essentially tool-less production, so that first printed part or first several hundred parts have a drastically lower price than possible through traditional means.?

Value of Weight

I was once told that if a part cost you $1/lb. on an automobile, it will cost you $10/lb. on an aircraft, and $10,000/lb. for a spacecraft.?While the exact numbers may be debatable, the value of weight is unquestionably orders of magnitude higher for spaceflight than for other means of transportation.?One of the key trends that has enabled the growth of companies like SpaceX is their ?success in reducing those orders of magnitude. It takes an incredible amount of energy to lift mass through the atmosphere against the pull of gravity. The more mass, the more energy, and energy is expensive. Reducing mass lowers energy costs and reduces a spaceflight’s carbon footprint.?

Additive manufacturing contributes to reducing weight and cost directly in two ways. First, designing for additive results optimizes parts for lower mass and reduces assemblies into single parts.?Second, because parts are being grown layer-by-layer with only the material needed instead of being machined from standard shapes down to complex light weight shapes, there is less material waste, otherwise known as a lower buy-to-fly ratio.?Low waste production of complex parts helps lower weight as well as the cost of the weight that remains. Loss is gain.

My first additive manufacturing project for space involved qualifying Stratasys FDM? components on the Atlas V rocket ?for United Launch Alliance in 2014. A number of these parts now fly on each Atlas V launch, but one type stands out in terms of the value of weight: ducting. The Atlas V used to fly with a ring of aluminum ducting that comprised 140 pieces, assembled by hand. With 3D printing, those 140 pieces of aluminum could be replaced by just 16 polymer components – saving weight, procurement risk, assembly labor, and ultimately, 57% cost. While this replaced components on a legacy vehicle, ?ULA’s CEO Troy Bruno stated at the time, “We are developing a new rocket, the Vulcan rocket, which will have an even higher content of additively manufactured parts.”

The ULTEM? material used by ULA for this duct was, at the time, being evaluated by a number of other space customers because it meets both flammability and out-gassing requirements appropriate for the space environment.?However, it is electrically insulative, and we started having users ask how they could post-process the material to be electrostatically dissipative (ESD) in order to be safe to use near electronics in the vacuum of space. For example, while building the ICESAT-2 vehicle, which is now in orbit, NASA Goddard Space Flight Center sought to 3D-print a bracket needed to hold fiber optic cables.?ESD was a required property.?Rather than help post-process the ULTEM material to meet this requirement, we developed a new material, based on Polyetherketoneketone (PEKK), tailored to meet this property.?Today this material is called ANTERO? 840CN03 and its use has spread throughout the space industry. Goddard’s initial need for just two of those brackets speaks perfectly to the volume fit for additive technology.

Not long after these parts were produced for NASA Goddard, NASA Johnson contacted us with the same challenge. That led to the qualification of ANTERO for NASA’s Orion vehicle in production by Lockheed Martin, where adoption moved from a couple of parts to a couple hundred parts.

Maxar, a company that produces satellites, has captured just how quickly adoption of additive has scaled within this market. During a webinar in 2020, Gina Ghiglieri from Maxar shared how after first flying 3D-printed FDM parts in 2016, by 2020 they were putting about 1000 printed parts on each satellite.

At Stratasys, we deeply engage with our customers to qualify the technologies we develop, but we also work with our customers across a wide range of other printing technologies and deliver parts to them from our Stratasys Direct Manufacturing facilities.?This extends our knowledge from polymers into metals as well.?And while metal 3D printing is considerably behind polymer 3D printing in production adoption, one of the truly well-matched applications for metal printing today is in rocket motors and the related turbomachinery.?I see an overwhelming proportion of flight-qualified 3D printed metal directly related to rocket propulsion today.?As with 3D printing more broadly, this is an area that gets mixed visibility, with publicly known relationships and advancements, such as SpaceX and their utilization of Velo3D and Rocket Labs, but a lot more that is still hidden from the public. That will change in the months ahead.

Additive manufacturing is even being put to work to help produce components that don’t lend themselves well to 3D printing. For example, investment casting of metallic engine components is a well- established traditional process. We are now seeing strong growth in 3D printing for investment casting, saving a time-consuming and expensive step by removing the need to create a mold for the sacrificial pattern.?This also significantly reduces development time, shrinking the design cycle from months to days.?Other applications include 3D-printed tools made from carbon fiber composites, and 3D-printed assembly fixtures and jigs, which accelerate and simplify lower volume manufacturing. ?

Where Do We Go From Here?

In the coming years, we will return to the Moon and we will go to Mars.?As these new frontiers are established, they will require a supply chain radically different than anything that’s been seen in the past. In any wave of frontier expansion, the first opportunity is in transportation – whether we are talking about trans-Atlantic sailing ships in the 1500s or the railroads in the US West in the 1800s. ?Rockets and spacecraft are no different.?The supporting supply chain for ships and trains was forests.?That’s not an option this time, but 3D printing is.?We will start by bring raw materials with us, whether that’s spools of filament or renewed raw material from recycling polymer packaging we bring with us.?Eventually we will utilize the resources available to us wherever we are. There is already a 3D printer on the International Space Station, and while we’re all watching Virgin Galactic, Blue Origin, and SpaceX launches, behind the scenes we are also seeing aerospace companies push 3D printing even further – for building vehicles on the ground today, and building whatever we might need in space tomorrow.

?