Photophoretic Flyers: Novel Propulsion for Near-Space Sensing

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.

Speaker: Ben Schafer, Rarefied Technologies