AS NASA builds its most powerful rocket, the Space Launch System (SLS), the US space agency is testing engines with 3D printed parts to cut costs of powering the heavy-lift rocket.

A major milestone towards that end was achieved this month when engineers successfully hot-fire tested an RS-25 rocket engine with a large 3D printed part, the US space agency said on Friday.

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The 3D printed part, called the pogo accumulator, is a beachball-sized piece of hardware that acts as a shock absorber by regulating liquid oxygen movement in the engine to prevent the vibrations that can destabilise a rocket’s flight, NASA said.

By 3D printing the hardware, more than 100 welds were eliminated, reducing costs by nearly 35 per cent and production time by more than 80 per cent.

Initial reports show the 3D printed hardware performed as expected, opening the door for more components scheduled for future tests, the US space agency said.

The test was part of the SLS Programme’s RS-25 affordability initiative — a collaborative effort between NASA and industry partner Aerojet Rocketdyne of Canoga Park, California, to reduce the engine’s overall production costs while maintaining performance, reliability and safety.

“As we build future RS-25s, NASA and our partners are taking advantage of innovative manufacturing techniques, including additive manufacturing, or 3D printing, to make the engines more affordable,” said Andy Hardin of NASA’s Marshall Space Flight Center in Huntsville, Alabama.

“3D printing is revolutionising manufacturing, and the pogo accumulator is the first of many components that can be built more quickly and less expensively,” Hardin said.

To minimise the costs of developing SLS, NASA selected the RS-25 engine.

“With modern fabrication processes, including additive manufacturing, the ‘next generation’ of the RS-25 will have fewer parts and welds, reducing production time as well as costs,” said Carol Jacobs, RS-25 engine lead at Marshall.

“Reducing the number of welds is very important,” she said.

“With each weld comes inspections and possible rework. By eliminating welds, we make the hardware more reliable and the process much more lean and efficient, which makes it more cost-effective,” Jacobs said.

The SLS Program has ordered six new engines to be built by Aerojet Rocketdyne for future flights.

The test conducted on December 13 was the first in a series of four tests designed to evaluate the operation of the 3D printed pogo accumulator, and the first in the series to certify the next generation of RS-25 engines.

The new, pogo accumulator will be included on all tests moving forward, NASA said.

“Future tests will incorporate more and more 3D printed components, with each test series building on the previous tests,” said Hardin.

The first SLS flight is scheduled to take place no earlier than 2019, but NASA recently stated that this launch could be pushed back to 2020 depending on the manufacturing and production schedule, Space.com reported.

This flight will use SLS to send an uncrewed Orion spacecraft around the moon and back to Earth. A crewed mission will follow later, in the 2020s.