Van Donkelaar at AIAA

A&A graduste student Finn van Donkelaar is working to change the current course of how large, acceleration-insensitive payloads will be launched into space. He caught the attention of AIAA, winning first place in the graduate division at the Regional AIAA Region VI Student Conference in Merced, California, in April. His winning paper, "Velocity Measurements of Projectiles Propelled by Underexpanded Supersonic Jets" has advanced to be presented at the upcoming 2019 AIAA SciTech Forum in January.

On his award, van Donkelaar says, "It was a heartwarming experience to present my ideas to industry professionals and have them express interest. I didn't expect to win or even get my paper accepted to the competition, so I was just in a daze after accepting my award."

The paper outlines a novel approach to launching large supplies payloads into space, as well as experimental validation of the concept. With human exploration of space poised to increase dramatically in the near future, vast amounts of supplies will be needed in space. Van Donkelaar's proposed system uses a powerful electrical arc to heat inert propellant before exhausting it through a rocket nozzle. The resulting jet of high-speed gas pushes the payload to orbital velocity, which would eliminate the need to carry huge amounts of fuel to reach space.

"I was able to test the idea on a small scale by using blank cartridges to push aluminum cans up to Mach 1.2," he reports. A&A Professor Carl Knowlen has taken note and will be helping to facilitate upcoming testing, "This propulsive concept of Finn's has been well thought out and analyzed. Finn has constructed a prototype for key demonstration tests that will be executed in the ram accelerator lab, which has the unique infrastructure and instrumentation to support this experiment." 

Van Donkelaar reports that the idea for the concept came from a mental challenge of thinking about how to launch something into space with a launcher no bigger than a backpack. While he hasn't quite developed a backpack-sized system, his launcher is quite compact and eliminates the need for a long barrel. Inspired by Professor Bob Breidenthal's Compressible Flow course, he is prototyping the system which has the advantage of potentially reducing atmospheric drag by redirecting the jet around the payload.

Teaming up with A&A Ph.D. student James Penna, van Donkelaar is advancing his prototypes. Penna, with a background in plasma physics, supplies a theoretical and physics foundation and complements van Donkelaar's grounding in structures and hands-on engineering. Penna says, "This project is fairly forward looking in that it aims to fill a gap in the upcoming space economy that current space launch schemes cannot, so in that respect it's similar to my Ph.D. research in nuclear fusion. But unlike fusion, the knowledge we need is already available, so all that remains is to build and test the prototypes. I'm fortunate to have started working with Finn, who had already built the first small prototype. With a little more luck, it won't be long until our first orbital launch tests!"

Finn van Donkelaar and James Penna displaying some of the components of their small-scale prototype of their space launch system.

Van Donkelaar comments on their partnership, "I'm really lucky to have a friend who's also highly competent in a related engineering field. There's no pressure or pretense to our technical discussions, so we're able to push through any difficulties with incredible speed." The two are collaborating on an upcoming paper, which will also be presented at SciTech. We look forward to seeing the duo's advances in space launches.