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Photophoretically levitating a communicating payload

Prof. Joost Vlassak
Abbott and James Lawrence Professor of Materials Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences

Ben Schafer
PhD Student, Harvard John A. Paulson School of Engineering and Applied Sciences

The mesosphere is an inaccessible region of the atmosphere (50-100 km altitudes) that is too high for conventional aircraft to generate lift, yet too low for satellites to maintain orbit. Flight in this near-space region would unlock a trove of climate data, communications pathways, and defense capabilities that no current hardware can achieve. We are developing an entirely new propulsion mechanism to enable mesospheric flight. The technology uses sunlight-induced thermal gradients to generate photophoretic forces, which propels lightweight devices upward without onboard power or fuel. Through the NSF I-Corps program, we validated the rapidly expanding customer segments of climate modeling, telecommunications, and defense. 


In previous work, we modeled that one type of photophoretic force, thermal transpiration, could loft 100 mg-scale payloads onboard a 10 cm-wide device at an altitude of 70 km. We verified these models by levitating a 1 cm-wide prototype under sunlight at near-space pressures. We now aim to develop these devices for commercialization. We aim to demonstrate that the devices can hold a variety of payloads and communicate while flying. This will help us redesign and fabricate our microscale structure at Harvard’s Center for Nanoscale Systems (CNS). Working with our collaborators, we will levitate a simple communications payload in mesospheric conditions and communicate with it remotely using our existing experimental setup.

Project Overview

Interested in this technology?  We are currently seeking partners in academia and industry to collaborate on further developments. 

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