In a groundbreaking development that could accelerate humanity’s journey to the stars, scientists have created an ultra-thin, ultra-reflective lightsail membrane designed to ride laser beams at unprecedented speeds. This advancement may one day enable small spacecraft to travel to neighboring star systems like Alpha Centauri in just a few decades—rather than thousands of years.

Developed through a collaboration between researchers at Brown University and the Delft University of Technology (TU Delft) in the Netherlands, the lightsail measures 60 millimeters on each side but is just 200 nanometers thick—thinner than a human hair. What sets this new design apart is its surface, which is patterned with billions of nanoscale holes. These features dramatically reduce the sail’s weight while enhancing its reflectivity, allowing it to better harness the pressure of light for acceleration.

“This work was a joint effort between theorists at Brown and experimentalists at TU Delft,” said Miguel Bessa, associate professor at Brown’s School of Engineering. “It’s exciting to see how our machine learning-guided design was brought to life in the lab. The process is cost-effective and scalable—exactly what’s needed to make interstellar travel feasible.”

Lightsails work by using light in the same way a sailboat uses wind: photons bounce off the reflective surface and push the craft forward. Unlike traditional rockets, which require massive amounts of fuel, lightsails need only light—offering a revolutionary propulsion method for deep space exploration. Such technology is central to efforts like the Breakthrough Starshot Initiative, founded by Yuri Milner and supported by the late Stephen Hawking, which aims to send microchip-sized spacecraft to the stars using ground-based lasers and meter-scale lightsails.

The team’s design uses single-layer silicon nitride, a lightweight and high-strength material ideal for lightsails. To boost performance, Bessa’s team applied an AI-driven optimization method that calculated the ideal shape and distribution of the nanoscale holes to maximize reflectivity and minimize mass. The thinner and more reflective the sail, the faster it can accelerate under a laser beam.

Once the design was finalized, Richard Norte’s team at TU Delft fabricated the lightsail using a new gas-based etching technique. “We’ve developed a method that lets us gently remove the material beneath the sail, leaving just the ultra-thin structure suspended,” said Norte. “If the sail survives fabrication, it’s surprisingly robust.”

Thanks to their innovative process, what would traditionally take up to 15 years and significant costs was completed in a single day at a fraction of the expense. The result is a lightsail with the highest known aspect ratio—large in area but minuscule in thickness—ever made.

Beyond interstellar travel, this technology represents a major step forward in nanofabrication and engineering. With further development, it could revolutionize our understanding of propulsion and our ability to explore the universe.

In the words of Bessa, “We’re not just designing a faster way to travel. We’re building the tools that could one day take us to the stars.”

By Impact Lab