NASA Is 3D-Printing a Better Rocket

5 minute read

Consider the injector. It’s a lowly little engine part about as big as a basketball, small compared to the more photographic components that surround it. Its job, however, is big. On a rocket, it shoots hydrogen gas and liquid oxygen into a combustion chamber to create the thrust needed to send that rocket into space. It also needs to endure the trip.

A conventional rocket engine injector may be comprised of a hundred different pieces, making it costly to assemble. On an object that costs several hundred thousand dollars per launch, and billions in development costs, any savings are welcome. It’s one reason why the cash-strapped National Aeronautics and Space Administration has been toying around with rocket parts made using an additive manufacturing process, better known as 3D printing.

In August, the agency test-fired a 3D-printed injector that withstood a record 20,000 pounds of thrust, which actually isn’t all that impressive. Paired with rocket boosters and the rest, the complete Space Launch System—a new heavy-lift vehicle that will power NASA’s deep-space missions starting in 2017—will create 9.2 million pounds of thrust at liftoff, the equivalent in horsepower of 208,000 Corvette engines revving up at once. What is impressive is the fact that the injector had just two parts and could produce 10 times as much thrust as any previously 3D-printed injector.

For NASA, additive manufacturing represents a way for the agency to stretch its technological capabilities and its $17 billion budget as it looks to build the next class of rocket engines to take its aircraft onto asteroids and to Mars. “The advances in the technology are finally getting to the point where we can see parts additively manufactured for demanding NASA applications,” says Dale Thomas, associate technical director at NASA’s Marshall Space Flight Center in Huntsville, Ala., where NASA has been trying out a variety of 3D-printed propulsion parts for more than a year. What the agency lacks, however, is the knowledge required to judge just how well 3D-printed engine parts will stand up during space flight. “We don’t understand the material properties really well and how they behave under stress,” Thomas says.

Enter the Integrated Product Team, a partnership formed in late May between the Marshall Center, the University of Alabama in Huntsville (as in “Go Chargers,” not “Roll Tide”), and the U.S. Army Aviation and Missile Research Development and Engineering Center, known as AMRDEC. The question at the central of the partnership: Is there a way to 3D-print material strong enough to insert into a working aircraft?

There is good reason to be uncertain about3D-printing parts that can be used in missiles topped with warheads or rockets ferrying astronauts. Which powdered metals will be easiest to print and strongest to deploy? What 3D-printing machines will work the best? The three groups believe that, by pooling their resources and trading notes, they will save time and taxpayer dollars developing additive manufacturing processes useful to the private sector, the military, and space exploration. They also believe they will manufacture higher-quality parts—lighter, stronger—than those created today through conventional machining techniques.

PHOTOS: A Look at America's Next Space Machines

The 16.5 foot diameter, titanium structure-supported heat shield fabricated by Lockheed Martin in Denver for Orion. Textron Defense Systems, outside Boston, covered the shield’s outer surface with Avcoat™, an ablative material system used on the Apollo spacecraft. The shield will have to withstand temperatures of 4,000 degrees F (2,200 C).
The 16.5 foot diameter, titanium structure-supported heat shield fabricated by Lockheed Martin in Denver for Orion. Textron Defense Systems, outside Boston, covered the shield’s outer surface with Avcoat™, an ablative material system used on the Apollo spacecraft. The shield will have to withstand temperatures of 4,000 degrees F (2,200 C).Patrick H. Corkery—Lockheed Martin
A test model of the Orion spacecraft with its parachutes was dropped high above the the Arizona desert on Feb. 29, 2012. This particular drop test—the latest of a series—studied the stability of the wake left by the Orion as it descended.
A test model of the Orion spacecraft with its parachutes was dropped high above the the Arizona desert on Feb. 29, 2012. This particular drop test—the latest of a series—studied the stability of the wake left by the Orion as it descended.NASA
The NASA team at the Michoud Assembly Facility in New Orleans has completed the final weld on the first space-bound Orion capsule, on June 22, 2012. The crew compartment is within this structure, which is then enclosed in the conical exterior.
The NASA team at the Michoud Assembly Facility in New Orleans has completed the final weld on the first space-bound Orion capsule, on June 22, 2012. The crew compartment is within this structure, which is then enclosed in the conical exterior. NASA
A test version of Orion arrived at the Kennedy Space Center on April 21, 2012. This model will be used for ground operations practice in advance of the first test flight.
A test version of Orion arrived at the Kennedy Space Center on April 21, 2012. This model will be used for ground operations practice in advance of the first test flight.NASA
At NASA’s Michoud Assembly Facility in Louisiana, the first space-bound Orion capsule is packed up for shipment to the Kennedy Space Center for final processing and outfitting.
At NASA’s Michoud Assembly Facility in Louisiana, the first space-bound Orion capsule is packed up for shipment to the Kennedy Space Center for final processing and outfitting. NASA
The vast expanse of High Bay 3 in the Vehicle Assembly Building dwarfs the Orion capsule and clean room, on May 24, 2012. The clean room is designed to keep particles inside the VAB from collecting on the outside of the spacecraft during processing.
The vast expanse of High Bay 3 in the Vehicle Assembly Building dwarfs the Orion capsule and clean room, on May 24, 2012. The clean room is designed to keep particles inside the VAB from collecting on the outside of the spacecraft during processing.Dmitri Gerondidakis—NASA
A model of Orion floats above an underwater mockup of the International Space Station in the 40-foot (12 m) deep Neutral Buoyancy Laboratory in Houston on April 25, 2013. The model is used to practice splashdown operations for Orion's first flight test in 2014. The yellow balls on the top of the capsule are flotation balloons which would flip the vehicle into the proper orientation if it were to turn upside down after landing.
A model of Orion floats above an underwater mockup of the International Space Station in the 40-foot (12 m) deep Neutral Buoyancy Laboratory in Houston on April 25, 2013. The model is used to practice splashdown operations for Orion's first flight test in 2014. The yellow balls on the top of the capsule are flotation balloons which would flip the vehicle into the proper orientation if it were to turn upside down after landing.Bill Stafford—JSC/NASA
This Orion boilerplate—essentially a dead weight mock-up—is loaded on a flatbed trailer for shipment to San Diego, where it is used to rehearse water recovery in the run-up to the 2014 test launch.
This Orion boilerplate—essentially a dead weight mock-up—is loaded on a flatbed trailer for shipment to San Diego, where it is used to rehearse water recovery in the run-up to the 2014 test launch. David C. Bowman—NASA
A RS-25D engine built for the shuttle program will instead be used to power the SLS booster.
A RS-25D engine built for the shuttle program will instead be used to power the SLS booster.NASA—KSC
Four RS-25 engines—here undergoing undergoing a hot-fire test—will power the core stage of the SLS.
Four RS-25 engines—here undergoing undergoing a hot-fire test—will power the core stage of the SLS.Aerojet Rocketdyne
A version of the J-2X engine burns brightly during a 278-sec. hot fire test Nov. 27, 2012 at NASA's Stennis Space Center in Mississippi. The J-2X will power the upper stage of of the SLS.
A version of the J-2X engine burns brightly during a 278-sec. hot fire test Nov. 27, 2012 at NASA's Stennis Space Center in Mississippi. The J-2X will power the upper stage of of the SLS.NASA—SSC
NASA engineers and contractors testing of a 67.5-in. (171 cm) model of the SLS in a subsonic wind tunnel at NASA’s Langley Research Center in Hampton, Va.
NASA engineers and contractors testing of a 67.5-in. (171 cm) model of the SLS in a subsonic wind tunnel at NASA’s Langley Research Center in Hampton, Va. NASA—LaRC
The launch-abort rockets and an Orion mock-up are prepared on the pad for their test flight at the U.S. Army's White Sands Missile Range in New Mexico, on April 8, 2010.
The launch-abort rockets and an Orion mock-up are prepared on the pad for their test flight at the U.S. Army's White Sands Missile Range in New Mexico, on April 8, 2010. U.S. Army White Sands Missile Range—NASA
Ground teams in White Sands, New Mexico, practice stacking test versions of Orion and its launch abort rockets, on Sept. 24, 2009.
Ground teams in White Sands, New Mexico, practice stacking test versions of Orion and its launch abort rockets, on Sept. 24, 2009. NASA
An artist's conception of the 38-story SLS with the orion on top, inside the Vehicle Assembly Building at Cape Canaveral.
An artist's conception of the 38-story SLS with the orion on top, inside the Vehicle Assembly Building at Cape Canaveral. NASA—MSFC

For the military, that means lighter missile components that can still handle vibrations during flight.

“You always want to save weight for an aviation platform. How do you save weight? Machine the part in a way to minimize frequency vibrations,” says James Lackey, acting director of AMRDEC in Huntsville. “Only through additive layering can you take advantage of what a mathematical formula tells you this design solution needs.”

Conventional machining can be thought of as subtractive manufacturing. You begin with a block of some material and gradually chop some off, a process that constrains the types of parts that can be designed. Additive manufacturing is different. Imagine instead a laser-centering machine that heats up and fuses together successive layers of powdered metals—inconel alloys, grades of steel, titanium, aluminum—to construct simpler rocket engine components. This is how NASA created the injector it test-fired a year ago.

“Those little boogers are incredibly complex,” Thomas says. “When you’re trying to manufacture them you throw away more than you use. With additive [we] can make an injector that in the past took about 15 to 20 pieces.”

Lackey and Thomas agree that the space agency’s foray into 3D printing is still in its earliest days. There is no working budget within AMRDEC or the Marshall Center for additive manufacturing experiments because both centers are still determining which 3D-printing technologies they need to invest in. Phillip Farrington, a professor of industrial and systems engineering and engineering management at the University of Alabama, says that whatever knowledge is gained through the Integrated Product Team could also be applied to streamlining manufacturing processes for automobiles, trains, and ships (a research project in which he’s currently engaged).

Right now, the work being done with additive manufacturing at the Marshall Space Flight Center shows the most promise, a reflection of the progress Thomas and his team are making in using the technology to not only manufacture injectors, but also valves, nozzles, and other parts necessary for propulsion in rocket engines.

“We’re seeing parts that can only be made using additive methods,” Thomas says. “We’re never going to get away from the traditional manufacturing process. But additive is going to have some real game-changing benefits.”

This article originally appeared on Fortune.com

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