Pukyong National University Presents Self-Levitating Aircraft Using Ultralight Nanostructure... Published in Leading Science Journal 'Nature'

Proof of Concept by Professor Kim Jonghyung and Joint Harvard-Chicago Team
Development of a Sunlight-Driven Near-Spacecraft Based on Nanostructures

Professor Kim Jonghyung from the Department of Materials Science and Engineering at Pukyong National University, together with a joint research team from Harvard University and the University of Chicago, has designed and fabricated an ultralight nanolattice structure capable of levitating using only sunlight. The team has experimentally demonstrated, for the first time in the world, the feasibility of flight in the Earth's mesosphere (altitude 50-100 km) using this technology.

Research team (from left: Professor Kim Jonghyung, Dr. Ben Schafer, Professor Joost Vlassak). Courtesy of Pukyong National University

The results of this research were published in the international journal 'Nature' on August 14.

The mesosphere, located 50-100 km above the Earth's surface, is too high for aircraft and weather balloons to reach and too low for satellites to observe, making it an atmospheric region that is difficult to access with existing technology.

This region can provide essential data for improving climate change predictions and the accuracy of weather models. However, due to the lack of observation tools, it has remained a 'blind spot in climate observation.'

The newly developed self-levitating aircraft can float semi-permanently using only sunlight, without any fuel consumption, and is expected to play an important role in future mesosphere exploration.

▲ Nanolattice-Based Design and Fabrication Technology, Expanded to Centimeter Scale

The research team developed a nanolattice-based design method that achieves both mechanical strength and lightness. Professor Kim Jonghyung led the design and fabrication of the structure, applying a new process that enables rapid production of centimeter-scale nanolattice structures, surpassing the previous limitation of only a few millimeters. This allowed the team to realize large-area structures that are ultralight yet mechanically stable, clearly demonstrating the practical applicability of nanolattice structures.

▲ Application of the 'Photophoresis' Principle for Light-Driven Flight

The team utilized the phenomenon of 'photophoresis,' a physical effect in which, under extremely low pressure, gas molecules reflected more strongly from a heated side of an object generate thrust. The researchers increased light absorption by depositing a layer of chromium on the underside of the aluminum oxide-based nanolattice structure, designing it so that the photophoretic force generated by the surface temperature difference could exceed the weight of the structure.

▲ Successful Simulation of Actual Mesosphere Environment

The structure fabricated by Professor Kim Jonghyung in Professor Joost Vlassak's laboratory at Harvard University measures 1 cm in diameter and 100 micrometers in thickness, with its interior composed of a precise nanolattice formed from 100-nanometer-thick thin films.

The team confirmed that the structure could levitate in a custom-built low-pressure chamber under conditions of 55% solar intensity and an atmospheric pressure of 26.7 Pa (equivalent to an altitude of about 60 km). This is the first experimental demonstration of sustained flight in the mesosphere.

▲ Expansion to Climate Observation, Communications, and Planetary Exploration

This technology can be equipped with ultralight sensors to collect real-time environmental data such as wind speed, atmospheric pressure, and temperature in the mesosphere, thereby improving the accuracy of climate models. Multiple self-levitating aircraft can also be used as a floating communication platform in the upper atmosphere to establish a low-latency communication network. Furthermore, the technology is highly promising for application on planets with thin atmospheres, such as Mars, and is being recognized as a next-generation planetary exploration technology, attracting interest from organizations such as NASA.

▲ Professor Kim Jonghyung: "A New Possibility for Nanolattice Structures"

Professor Kim stated, "This research represents the development of nanolattice structures from simple laboratory materials into structures applicable in real atmospheric and space environments," adding, "In the future, we will integrate communication functions and various sensors to expand into real-time observation and planetary exploration technologies."

Professor Kim Jonghyung is conducting follow-up research to improve the performance and reliability of the structure and is also committed to fostering creative talent capable of conducting interdisciplinary research that transcends the boundaries of materials science within the Department of Materials Science and Engineering.

Ultralight self-levitating aircraft using nanostructures.

This research was supported by the Harvard Star-Friedman Challenge and the U.S. National Science Foundation (NSF). The developed technology has been transferred to the startup Rarefied Technologies through the Harvard Office of Technology Development and is currently being commercialized.

This content was produced with the assistance of AI translation services.