Tuesday, 03 November 2025 at Noon | 521 Cory Hall (Hogan)
Registration not required.
Benjamin Schafer, Ph.D.
CEO & Co-Founder | Rarefied Tech
Host: Kris Pister, BSAC Co-Director
ABSTRACT
While photophoresis, or “light-driven motion,” has long explained how aerosol layers remain aloft in the middle atmosphere, practical applications have only recently been gaining attention. Advances in nanofabrication now allow us to build lightweight structures that can propel themselves upward using photophoretic forces alone. These “photophoretic flyers” can sustain flight in near-space (30–100 km altitudes), a region that is too high for aircraft and balloons and too low for satellites. I will review the physics of photophoresis, recent experimental tests and models that demonstrate its viability for propulsion, and pathways for scaling the technology. I will also outline applications directly relevant to BSAC’s mission, including wireless/RF communications from microscale payloads, distributed platforms for remote sensing, and data collection in the extreme environments of near-space and Mars. By bridging the observational gap between balloons and satellites, photophoretic flyers could soon be a new platform for scientific discovery and collaborative instrument development.
BIO
Ben Schafer is the CEO and Co-Founder of Rarefied Technologies and an Associate Researcher at the Harvard University John A. Paulson School of Engineering and Applied Sciences. Rarefied Technologies is a startup based in Albuquerque, NM developing photophoretic levitation for near-space flight. Ben's research focuses on innovative designs for photophoretically flying structures, the experimental fabrication and testing of flying devices, and the application of this technology to address challenges in atmospheric and space science, remote sensing, and telecommunications. He received his Ph.D. in Applied Physics from Harvard University in 2024. He is a former researcher at Los Alamos National Laboratory and NIST, and is currently a Breakthrough Energy Fellow and a New Mexico LEEP Fellow.
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