New Method of 3D Printing Electronics Tested in Weightlessness by Iowa State ‘NINJAS’ Researchers

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Researchers at Iowa State University have successfully tested a new approach to 3D printing electronics in weightless conditions.

Instead of gravity, the team’s technology effectively uses electrical force to print conductive inks onto a glass base layer by layer, in a way that allows the creation of complex circuitry. Working with NASA, engineers aim to develop the process into a way to produce sensors in space that reduces astronauts’ reliance on carrying spare parts and makes long-haul spaceflight more feasible.

“For future NASA missions, space exploration missions, they not only want to send people back and forth, but also long-term facilities,” says Hantang Qin, principal investigator of the research team. “That’s what we’re trying to do. We build the printer, so that it can stay on the International Space Station (ISS) or on Mars for a long time.

NINJAS researchers at Iowa State University during their parabolic test flight. Photo via Steve Boxall/Zero-G.

Repair electronics on the fly

On board spacecraft, it is not uncommon for electronic equipment such as sensors to break, causing problems that could compromise their missions. In the case of the humidity sensors on board the ISS, for example, these are essential to the safety of its crew, and if the devices malfunction, they must be urgently replaced or repaired.

While sending replacements to base might seem like the obvious solution to this problem, it does add weight to the deployed craft during resupply missions, which, in turn, makes the operation considerably more expensive to perform.

To circumvent this problem, a group of researchers known as the Zero Gravity Inkjet Printing Team for Aeronautics and Space or “NINJAS” came up with an alternative. Developed at Qin’s Flexible Electronics and Additive Printing Laboratory, the engineers’ approach is to use an electrohydrodynamic inkjet printing mechanism to create parts from new silver titanate inks and patent pending barium.

According to the team, these materials are well suited for electronics production because they enable ultra-stable high-resolution printing, and with further R&D, they could enable the creation of a new class of flexible sensors, soft robotics, of printed circuits, semiconductors and other micro-devices, both in space and here on solid ground.

As a first step in putting their approach to the test, Qin and his team built a prototype 3D printer in late 2021, while fellow Iowa State member Shan Jiang worked from his lab to perfect its set of conductive inks before the parabolic flight tests.

“The main goal of our experiment was to print a conductive circuit pattern in microgravity,” Qin added. “We tested several types of ink with different material properties, such as density, surface tension and permittivity, while identifying the optimal operating conditions, including voltage, pulse frequency and nozzle orientation. .”

Hantang Qin and Shan Jiang, who led the project from Iowa State University.
Hantang Qin and Shan Jiang, who lead the project from Iowa State University. Photo via Iowa State University.

The NINJAS weightless experience

Once their prototype was ready for testing, the NINJAS crew flew it to Fort Lauderdale, Florida, where it was flown by a refitted aircraft in conditions simulating those of outer space. The plane was able to achieve this by continuously flying up and down at 45º angles, allowing the team and their experiments to experience short periods of weightlessness in microgravity at the very top of this curve.

However, while the engineers acknowledge that parabolic flight testing was the only way to gauge their 3D printer’s performance without going into space, they point out that getting the system to work in zero gravity was no small feat. business in itself, and describe it as akin to “jumping off a 30,000 foot high building for 20 to 30 seconds.”

“The zero-gravity environment wasn’t even that hard to adjust to feel,” said Matthew Marander, one of the Iowa State students who flew on the project. “What I felt was more difficult to deal with was the feeling of quickly transitioning between hyper-gravity, normal gravity and weightlessness. Switching between them so quickly can feel a little disorienting.

In terms of printer performance, Jiang concluded that the first day of the three-day test was a learning experience for everyone involved, but during the second and third the team was able to 3D print.” pretty patterns. After their initial success, the researchers have now doubled down on their research, developing upgrades for their system and materials ahead of a second test in May 2022.

Through their $420,000 project, Jiang added that the team “ultimately wants to help NASA develop a platform that can dramatically expand the materials and devices they can make in space,” and they have therefore set themselves the longer-term goal of offering a new nozzle head for the ISS printer before 2024.

Crew working inside the International Space Station.  Photo via NatGeo/ISS: 24/7 ON A SPACE STATION
Crew working inside the International Space Station. Photo via NatGeo/ISS: 24/7 ON A SPACE STATION.

3D printing in orbit in action

NASA continues to spend a lot of time, effort and money on performing 3D printing experiments in Low Earth Orbit (LEO), with the most promising technologies being tested aboard the ISS. Last year, a European Space Agency consortium developed an early-stage FFF 3D printer said to be able to create “unlimited length” parts, which has been earmarked for the ISS.

In the past, companies like Made in Space (now Redwire) have also helped build systems for the ISS, and the company has played a key role in the development of the plastic recycling facility of the station for 3D-printed parts in 2019. Known as the ‘Braskem Recycler’, the machine converts plastic waste from the ISS into raw materials, allowing it to reduce its reliance on space missions. supply and establish a near-closed-loop production configuration.

Away from the ISS, researchers from the University of Applied Sciences in Munich have also developed an orbiting satellite 3D printer, which may be able to create solar panels or antennas in the vacuum of space. Like Iowa State’s NINJAS program, the project was started with the goal of reducing unnecessary weight aboard spacecraft and allowing them to carry more vital cargo such as fuel.

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Featured image shows Iowa State University NINJAS researchers during their parabolic test flight. Photo via Steve Boxall/Zero-G.

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