As NASA explores frontiers beyond planet Earth, the space agency is doing a different kind of exploration closer to home.
The agency is delving deeply into the benefits of additive manufacturing, or 3D printing, to produce everything from rocket engine parts to space suits and even for making tools in space. The technology fabricates parts and products by building them layer-by-layer with various materials, such as metal, plastic, ceramic, or composites and now possibly raw materials for food.
According to John Vickers, manager of advanced manufacturing at NASA’s Marshall Space Flight Center, Huntsville, AL, this work helps achieve the goals of NASA’s Space Technology Mission Directorate and its Game Changing Development (GCD) program to explore novel ideas and new technologies that can change the world. “The goal is to produce technology that’s revolutionary, primary, and disruptive in the way we do business,” says Vickers. “That’s different from what we might do for a near-term mission. It’s revolutionary rather than small incremental. It’s inherently high risk but it’s also high payoff. We’re looking at getting to a point where the risk is low enough, not totally eliminated, but mitigated, where we can tip the balance, and hopefully the technology will be picked up either by NASA or by industry.”
Reducing Costs on Earth
The agency is focusing on applications in two areas, earth-based and in flight. The main earth-based application is for rocket engine parts, in order to reduce costs and reduce production time, which can take up to two years using traditional methods.
“It gives our designers almost an endless set of new design options,” Vickers says. “In the past we might have made a rocket engine component, an injector for example, with hundreds of pieces of parts. With additive, we can shrink that down, in some cases, from hundreds to a single part. That takes out all assembly time. It takes out many, many inspections on the joints, many [being] problem areas like the welds.”
In August, NASA tested the largest 3D-printed rocket engine component so far, an injector, one of the most expensive and largest parts, which delivers propellants to power an engine. The test was considered a milestone because of the size of the injector and the record thrust level of 20,000 pounds generated by the rocket firing, 10 times more thrust than any injector previously fabricated using 3D printing. The injector was made using selective laser melting, a process that builds up layers of nickel-chromium alloy powder using a 3D printer. The injector was similar in design to injectors for large engines, such as the RS-25 engine that will power NASA’s Space Launch System (SLS) rocket, a new heavy launch vehicle for deep space human missions scheduled for its first launch in 2017. It had only two parts, compared to 115 parts for a similar injector produced by traditional manufacturing methods.
NASA’s goal is for additive manufacturing to be able to have some impact on the first SLS mission, Vickers said. In an earlier test, engineers built two subscale injectors using 3D printing in three weeks, which typically took six months when manufactured by traditional methods. The 3D printing process cut manufacturing costs in half.
Applications in Space
To benefit from additive manufacturing during a flight, NASA was an early adopter, working with the technology since it was introduced in the late 1980s. However, they only recently felt they had developed it to the point that it could be used in space, Vickers says. NASA now has a 3D printer that they plan to launch on a rocket to the space station next year in a demonstration mission. The objective is to prove that the machine can work in zero gravity and with other limitations of operating on a spacecraft in space and ultimately be able to produce parts and build tools on demand for the crew, especially on long duration missions to Mars or on an asteroid. “The further you get into space, the fewer supplies you can take with you,” he adds.
Another project of NASA is looking at the feasibility of using additive manufacturing to make a variety of food in space using shelf-stable ingredients. Vickers says while that is not his area of expertise, he’s not surprised. “It just shows you the extent of the possibilities,” he says. “The computer makes an input to the machine and out pops the product. If you have the raw materials for food, there is no reason you can’t make pizza.”
Vickers adds that while there is a lot of excitement and buzz about additive manufacturing, some say there is a lot of hype too. “I don’t believe there is hype,” he says. “The progress that we’ve made and other industrial sectors as well – the automotive industry for one – that’s real progress. We’re building real hardware for rocket engines. That’s real proof that it’s not hype.”
NASA, an early adopter of 3D printing, is optimistic that the technology will allow production of everything from rocket engine parts to space suits and even for making tools in space.
Nancy S. Giges is an independent writer.
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