3D Printed Rocket Thrusters Could Change Small Spacecraft Industry

3D printing has made a place for itself firmly in the center of the aerospace industry, with the technology being used to fabricate rocket engines and components, satellites and more. Even fuel itself can be 3D printed, and that’s what graduate students at Utah State University did recently with an experiment that was sent into space this week by NASA.

The experiment was designed and built by aerospace engineering graduate students Marc Bulcher, Zac Lewis and Rob Stoddard, and aerospace engineering professor Stephen Whitmore. It involved a new type of thruster, developed and patented by Whitmore, 3D printed from ABS. Thrusters do not boost rockets into space but instead orient them in zero gravity. The thrusters developed by the USU team do not burn conventional liquid rocket fuel, but are instead fueled by the plastic itself.

“The vast majority of liquid rocket fuels used for space propulsion are extremely dangerous and toxic,” said Bulcher. “Hydrazine, for example, powers thrusters that control satellites and small spacecraft. Hydrazine is carcinogenic, expensive to make and presents many safety and environmental challenges.”

According to Whitmore, 3D printing allowed the team to “blend and compose certain printable plastics into material that contained advantageous properties of rocket fuels.”

“We were able to engineer some fairly interesting plastics that, it turns out, made really, really good rocket fuel,” he said. “Basically, we’re printing our fuel materials out of the same stuff you would use to make Legos.”

Bulcher started working with Whitmore in 2016 and didn’t quite grasp the concept of the liquid fuel-less thrusters at first.

“That didn’t make much sense to me,” Bulcher said. “So I did some more research into the chemistry of it and was like, ‘OK, these are plastics very similar to hydrocarbon, and under the presence of heat pressure, they’ll combust.'”

To test the thrusters, the team mounted two of them to a small test frame inside the large sounding rocket. When the rocket reached the right altitude, its mid-section fell away and exposed the thrusters to the vacuum of space. The test was successful, Whitmore said, and each thruster fired five times.

Earlier this week, NASA launched a rocket from Wallops Flight Facility carrying the thrusters as well as experiments from three other universities, as part of its Undergraduate Student Instrument Project (USIP). The rocket flew in space for approximately seven minutes and reached an altitude of 107 miles before parachuting back to Earth and landing in the Atlantic Ocean.

The next step for the USU team is to determine if exhaust from the thrusters contaminated a nearby optical sensor. If they turn out to burn clean, they could change the way small spacecraft thrusters are made, according to Whitmore. Propellants like the one they developed won’t completely replace hydrazine, he said, nor will they replace the more powerful fuels used to launch rockets, but they could represent a new cheaper, greener and more flexible way to power thrusters.

“This is the first time a USA-developed green propellant has been flight tested in space,” said Whitmore. “It’s an exciting time for us because this gives our students unparalleled industry experience, and at the same time we’re developing something that could completely change the small spacecraft industry.”

Discuss this and other 3D printing topics at 3DPrintBoard.com or share your thoughts below.

[Sources: USU, HJNews / Images: USU unless otherwise indicated]