Breakthrough in Light-Driven Propulsion: Graphene Aerogels in Microgravity

Recent experiments conducted by researchers from the Université Libre de Bruxelles in Belgium and Khalifa University in the United Arab Emirates during the European Space Agency's (ESA) 86th parabolic flight campaign have revealed that graphene aerogels exhibit significantly enhanced propulsion capabilities in microgravity. These ultralight materials, which can weigh as little as one-hundredth of a gram per cubic centimeter, produce thrust when illuminated by a laser. The study, published in *Advanced Science*, indicates that graphene aerogels can generate thrust approximately fifty times greater in microgravity compared to ground conditions.

European Space AgencyESA propels graphene aerogel with lightGraphene aerogels produce fifty times more thrust in microgravity than on the ground

The propulsion mechanism of graphene aerogels is primarily thermal. When exposed to laser light, a thin surface layer of the aerogel heats up, creating a temperature gradient that drives gas molecules through the material's pores. This phenomenon, known as Knudsen pumping, combined with photophoretic forces, results in a net thrust in the direction of the laser beam. In microgravity, the aerogels achieved a peak thrust of 0.6 millinewtons (mN) and accelerated to velocities of 1.7 meters per second (m/s) within 0.03 seconds of laser exposure. In contrast, under normal gravity, the same samples produced a maximum thrust of only 11 micronewtons (µN) and reached a peak velocity of just 0.06 m/s.

Graphene aerogels produce fifty times more thrust in microgravity than on the groundEuropean Space AgencyESA propels graphene aerogel with light

The findings from these experiments suggest a paradigm shift in the engineering of light-driven propulsion systems for small satellites and other space applications. The significant increase in thrust and responsiveness of graphene aerogels in microgravity opens new avenues for their use in micro-propulsion and attitude-control systems. The ability to optimize pore architecture independently of density allows for tailored designs that can meet specific propulsion requirements.

Graphene aerogels produce fifty times more thrust in microgravity than on the groundESA propels graphene aerogel with lightEuropean Space Agency

Marco Braibanti, ESA's project scientist for the experiment, noted, "The reaction was fast and furious... it was all over in 30 milliseconds," highlighting the rapid acceleration of the aerogels in microgravity. Ugo Lafont, an ESA materials physics and chemistry engineer, emphasized the potential of graphene aerogels to "save us large amounts of fuel and hardware in space," indicating a move towards propellant-free propulsion technologies.

ESA propels graphene aerogel with lightEuropean Space AgencyGraphene aerogels produce fifty times more thrust in microgravity than on the ground

While the results are promising, some experts caution that further research is needed to fully understand the implications of these findings and to develop practical applications. The transition from fundamental science to operational technology may present challenges that require additional investigation.

ESA propels graphene aerogel with light

The research team plans to continue exploring the capabilities of graphene aerogels, particularly in optimizing their designs for future space missions. ESA is also assessing the broader potential of two-dimensional materials for various space technologies, including solar sails and other propulsion systems.

ESA propels graphene aerogel with lightGraphene aerogels produce fifty times more thrust in microgravity than on the groundEuropean Space Agency

• “The stronger the laser, the greater the acceleration.” — Marco Braibanti, ESA Project Scientist

European Space Agency

• “We are opening the path to a propellant-free propulsion future.” — Ugo Lafont, ESA Materials Physics and Chemistry Engineer

ESA propels graphene aerogel with light

The advancements in graphene aerogel propulsion represent a significant step forward in the quest for efficient, lightweight propulsion systems in space exploration.

ESA propels graphene aerogel with light