Student explores combined effects of gravity and cosmic radiation

Preparing for outer space

By Malorie Sougéy

Matthew Culbertson is researching the effects of space from a lab on Earth.

Culbertson, Kansas State University senior in physics and mechanical engineering, puts his studies in the College of Arts and Sciences and the Carl R. Ice College of Engineering to use conducting research. He is working with Amir Bahadori, associate professor, Steve Hsu Keystone research scholar and Hal and Mary Siegele professor in the Alan Levin Department of Mechanical and Nuclear Engineering. Their research sets the stage to characterize how human cells would react to being irradiated in partial gravity, which will give scientists a better understanding of what happens inside the human body in space.

Their research began with a project exploring active shielding — creating a charged electric field to repel highly ionized cosmic radiation particles.

“If we build a base on the moon or Mars, we’ll want shielding there since there is no atmosphere to absorb radiation or magnetic fields to deflect the particles like we have on Earth,” Culbertson said. “Active shielding around the base or spacecraft could repel the particles and reduce astronauts’ absorbed radiation dose.”

Culbertson has tested shielding setups using specialized software, including the Active Shielding Particle Pusher and COMSOL Multiphysics programs, to simulate individual radiation particles millions upon millions of times and see how the particles would react to active shielding. The simulated active shielding system moved radiation particles around the shield, indicating active shielding could be effective in space.

To test how cell samples react to space radiation, Culbertson customized and programmed a random positioning machine — a device consisting of two rotating frames, one inside the other, that operates on two axes. A pathing program directs the movement of the frames, which reproduces the conditions for zero or partial gravity for a cell sample.

“We wanted an on-the-ground analog for how a cell sample would react in space without spending millions of dollars on actually sending a sample into space,” Culbertson said.

Working with a prototype created by a previous team, he revolutionized the pathing system to produce varied gravities — such as Martian and lunar partial gravities — and optimized the machine’s efficiency.

The random positioning machine can be placed at the beam ports of K-State’s TRIGA Mark II nuclear reactor facility, where high-energy neutrons are expelled directly toward the cell sample.

“The machine’s frame is designed to limit how much radiation is blocked or deflected from the beams,” Culbertson said. “You put the cell sample at the center of the machine and the beam port so the cell sample can be irradiated while it’s on the machine, effectively replicating the desired gravity and radiation of space for the sample.”

Culbertson received a prestigious Barry Goldwater Scholarship for his work with the random positioning machine and presented his research at the 2023 American Nuclear Society’s annual conference.