Published: Feb. 4, 2020 By

Associate Professor Gregory Whiting and his research group are preparing for the thrill of a lifetime: two parabolic flights, each expected to provide around ten total minutes of reduced gravity to test and model how 3D printing of functional materials works in lunar gravity.

Gregory Whiting headshot

Associate Professor Gregory Whiting 

This technology is one of 25 promising space technologies selected by NASA for testing on an aircraft that simulates spaceflight, a high-altitude balloon or a suborbital rocket. The process is meant to be iterative, providing researchers with a quick way to collect data and refine their innovations for possible inclusion into NASA missions to space and the moon. The grant will award $500,000 over the course of 18 months to Whiting and co-principal investigator Robert Street, a printed electronics expert at PARC, A Xerox Company.

So why send a 3D printer to space? One reason is so manufacturing can be completed without needing parts from Earth. If researchers can determine the best methods for printing in space, they may be able to print complex electronic devices like life support systems using multi-functional paste-like inks.

Already, Whiting’s research group, the Boulder Experimental Electronics and Manufacturing Lab has successfully printed a multi-functional composite material able to absorb and expel gasses in the lab. This material may be adapted for removal of CO2 or other gasses in a confined space, such as the International Space Station.

About Parabolic Flights

Parabolic flights simulate reduced gravity environments and are useful when training astronauts or in carrying out experiments. The aircraft fly in a pattern that resembles a parabola, repeatedly climbing and descending. At the top of the parabola, reduced gravity is achieved for roughly 20-30 seconds. At the bottom of the parabola, the forces are equivalent to two times Earth’s gravity. On a typical flight, 20-30 repetitive parabolas are completed, providing time for experimentation or training.

“By far the most exciting part of this project was the first time we ran current through the printed composite,” said Jamie Thompson, a PhD student collaborating with Whiting’s group and a visiting researcher at PARC. “We could instantly feel the heat being given off by the device.”

Before they can manufacture the composite material in space, however, Whiting and his research group must first understand how gravity affects the shapes that can or cannot be printed.

“Think peanut butter,” said Whiting. “If you pull the peak up, it will stay in place for a little while, but with one-sixth the gravity, it will settle more slowly than it does on Earth. The same goes for printing these paste-like functional inks.”

To model these differences, the team will perform a series of printing challenges, including overhangs, bridges, sharp edges, curves and movements that require higher printing speeds in both Earth’s gravity and microgravity.

3D printing in space Charlotte Bellerjeau
Above: Charlotte Bellerjeau, an aerospace undergraduate researcher gives a demonstration of the 3D printer used to print multi-functional composite materials in the BEEM Lab. 
Top: Charlotte Bellerjeau holds two 3D printed components capable of absorbing and expelling gasses.

“We sometimes think doing things in space will be harder than on Earth, which is mostly true,” said Whiting, “but in this case, we think that the reduced gravity found on the moon could actually be quite beneficial, enabling us to print structures with these materials that would otherwise be difficult to make.”

For example, he said when printing layer upon layer on Earth, a large gap in a printed structure cannot be crossed without filling it in. With less gravity, bigger gaps could potentially be bridged.

Whiting said he is grateful for the expertise of collaborators at PARC who will deliver a test printer prepared to acquire both ground and flight data. By measuring most everything about the printing process, the researchers will have a better idea how to print desired shapes in space. Accelerometers, other sensors, image recognition software and lasers will likely be incorporated around the printer to accurately measure printed geometrical features during the flights.

Whiting, who recently joined the Multi-functional Materials Interdisciplinary Research Theme at the College of Engineering and Applied Science, said he can imagine his group working on additive manufacturing and multi-functional materials long into the future. It seems his level of excitement for this particular research is met only by the group’s excitement for the upcoming parabolic flights.

“Taking the project from materials development all the way to micro and lunar gravity testing in the near future has been an amazing process,” said Charlotte Bellerjeau, an undergraduate researcher in the BEEM Lab studying aerospace engineering. “The parabolic flights coming up are exciting, but I'm also looking forward to future applications for this technology that extend beyond spaceflight.”