Authored by John F. Hornick
The Ultimate Space Exploration Machine
If Apollo 13 had a 3D printer (invented not too long after the event), the phrase "Houston, we have a problem" may not have entered the lexicon. Forty-four years later, NASA moved to prevent the use of that phrase by outfitting the International Space Station with a 3D printer in 2014. In a test with far-reaching implications for the future of space exploration, NASA, with the help of Made In Space Inc., essentially emailed the digital blueprint for a ratchet wrench from NASA’s Huntsville Operations Support Center to the space station, where it was 3D printed in plastic. The whole process, from conception, to design, to safety approval, to transmission, took less than a week, and the wrench was printed in about four hours, in zero gravity. According to Made In Space, the machine is capable of printing more than a third of the spare parts needed on the ISS.
NASA’s test highlights one of the great strengths of 3D printing: making things where and when they are needed. Another 3D printing strength is making complex parts that cannot be made in any other way. Another strength is making parts customized to the user’s needs. Another is making one-of-a-kind parts, instead of the one-of-a-million parts of mass production. Another is manufacturing simplification: a part, such as a fuel nozzle, that is assembled from 20 traditionally manufactured pieces, can be 3D printed as one part. For space exploration, 3D printers also help solve the problem and reduce the great expense of launching equipment and supplies into space and assuring that spare parts are there when needed. These strengths make 3D printers the ultimate space exploration machine.
Making Parts, Layer by Layer
Most people have heard of 3D printers but view them as simple machines that print out Yoda heads, layer by layer. Although Yoda is an apt symbol for 3D printing in space, 3D printing is so much more. One type of 3D printing is called Material Extrusion, which is how both the space station’s ratchet wrench and Yoda heads are made. This process is relatively simple: extruding thermoplastics through a nozzle, for layered manufacturing. Other processes 3D print parts jetting layers of plastic or metal droplets, or by using lasers or electron beams to fuse layered parts from plastic or metal powders. NASA is testing another type of 3D printing process called Directed Energy Deposition, which uses an electron beam and metal wire to build parts in zero gravity. Lockheed Martin is using the same process to 3D print rocket fuel tanks from titanium wire. 3D printing the tanks is much faster than making them by the traditional method—casting—and costs half as much.
3D Printing Is Rocket Science
Eventually the 3D printers in space will be able to print much more than plastic wrenches, just as they do now on Terra Firma. In 2013, NASA test fired a 3D printed fuel injector—the heart of the engine—for its Space Launch System, which will power the Orion spacecraft. The part was 3D printed by Aerojet Rocketdyne using a process called Powder Bed Fusion, where a laser melts metal powders layer by layer to build up a finished part. By 3D printing the part, rather than using traditional manufacturing methods, NASA reduced the production time from more than a year to only four months, with a 70% cost reduction. 3D printing also enabled the fuel injector’s design to be reduced from 160 pieces to just two.
In 2015, NASA used Powder Bed Fusion to 3D print a copper rocket combustion chamber liner designed to withstand high heat and pressure. By 3D printing the part, NASA integrated 200 complex cooling channels between the inner and outer walls. Even if this part could be made by traditional methods, which is doubtful, 3D printing made it faster and cheaper. NASA has also tested a rocket engine turbopump made with Powder Bed Fusion. The 3D printed design is more complex than its traditionally made counterpart, with almost half as many parts, and could not even be made by traditional methods.
Because of the difficulty and expense of launching equipment into space, 3D printers may eventually be used to manufacture spacecraft in space. NASA’s SpiderFab project will employ robots to assemble spacecraft components 3D printed in space.
NASA is not alone in using 3D printing for space travel. Elon Musk’s SpaceX used Powder Bed Fusion to 3D print its SuperDraco thruster, which powers its Dragon spacecraft. According to Musk, "through 3D printing, robust and high-performing engine parts can be created at a fraction of the cost and time of traditional manufacturing methods. SpaceX is pushing the boundaries of what additive manufacturing can do in the 21st century."
Mars and Moons
With its eye on a Mars mission, NASA issued a design challenge that resulted in a new 3D printing process called "selective separation sintering," which is intended to combine gravel found on Mars with magnesium oxide (also found on Mars) and 3D print things like bricks and tiles capable of withstanding the heat and pressure of a spacecraft’s engines. Deep Space Industries has a similar plan: using robots to mine asteroids and feed the mined raw materials to 3D printers, which will make more robots, mining equipment, and spacecraft to push humans deeper into the cosmos. One cannot help wondering why The Martian’s screenwriters didn’t give Matt Damon such a 3D printer.
Knowing that people will need cool wheels on other planets just as they do on Earth, Audi, the German car maker, and a team called Part Time Scientist 3D printed the unmanned Lunar Quattro rover from titanium and aluminum. Its first assignment may be to visit the Lunar Roving Vehicle, which NASA left on the moon over 40 years ago. To explore parts of moons and planets that rovers can’t reach, NASA is also designing 3D printed drones called Extreme Access Flyers that hover over rough terrain and collect samples.
Some Space Is Closer to Home
Not every 3D printed part will help humans to explore space. A piston 3D printed by Aerojet Rocketdyne in 2014 will help launch small spacecraft, such as satellites, into earth orbit. To meet U.S. requirements for a reliable on-demand satellite launch system, the Lawrence Livermore National Lab is 3D printing complete rocket engines, no assembly required. The lab printed the prototype in 8 days for $10,000, which was much faster and much less expensive than traditional methods.
Other Countries Are Helping Humans to Boldly Go
Advances in 3D printing for space exploration are coming from around the world. In 2015, England’s University of Birmingham 3D printed a complex, high-performance ceramic rocket engine thruster, at a fraction of the cost of making such a part with traditional methods. New Zealand’s Rocket Lab 3D printed its Rutherford rocket engine, named after native son Ernest Rutherford, a Nobel Prize–winning physicist. Using Powder Bed Fusion, Rocket Lab printed the engine’s thrust chamber, injector, turbopumps, and main propellant valves, using titanium alloys. Some of these parts could not be made by traditional methods and were 3D printed in days rather than months. The European Space Agency 3D printed a platinum rocket engine combustion chamber and spacecraft thruster nozzle. The parts performed at least as well as their traditionally made counterparts, at greatly reduced cost.
Kids Are the Key to Reaching for the Stars
As humans push beyond Earth, innovators will be just as important as 3D printers, if not more so. Tomorrow’s innovators are kids today. Kids are just starting to use simple, inexpensive, consumer-grade 3D printers. Kids will not only grow up with 3D printing technology, the technology will grow up with the kids because they will contribute to its advancement. They will learn by using their own machines, teaching themselves, and improving the machines as they go. But they will also need access to advanced machines, processes, and materials. Schools and governments are beginning to pave the roads that kids will follow, from printing toys at home today to making high-tech parts and products in the factories of tomorrow. Today’s young innovators will 3D print our future and push us to the stars.
Originally printed in NaSPA Technical Support Magazine in July/August 2016. This article is for informational purposes, is not intended to constitute legal advice, and may be considered advertising under applicable state laws. This article is only the opinion of the authors and is not attributable to Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, or the firm's clients.