Caltech Researchers Take First Steps Toward Lightsail-Powered Interstellar Travel
In a groundbreaking step toward interstellar exploration, researchers at Caltech have developed a method to test ultrathin "lightsails"—a revolutionary concept that could one day enable spacecraft to travel to distant star systems like Alpha Centauri.
Inspired by the Breakthrough Starshot Initiative, a program launched in 2016 by Stephen Hawking and Yuri Milner, the lightsails aim to achieve unprecedented speeds by harnessing the power of laser propulsion. Unlike traditional spacecraft, these tiny probes equipped with reflective membranes could be propelled to interstellar distances using high-powered lasers from Earth.
"These lightsails have the potential to travel faster than anything we've ever built, opening the door to direct exploration of star systems currently accessible only through telescopes," said Harry Atwater, Chair of Caltech’s Division of Engineering and Applied Science.
Atwater and his team have now taken the first experimental steps toward this ambitious goal. Using cutting-edge nanotechnology, they created a miniature tethered lightsail just 50 nanometers thick and developed an advanced platform to measure how laser radiation pressure interacts with it.
Turning Theory into Reality
One major challenge in lightsail development is understanding how the sails behave under the intense force of laser beams. To address this, the Caltech researchers crafted a silicon nitride "trampoline" membrane, only 40 microns across, suspended at its corners by delicate springs. By directing a visible laser at the sail, the team measured its motion and stiffness with remarkable precision—down to the picometer scale.
"The dynamics of a tethered sail are complex, but this setup allowed us to measure both the force and power of the laser with extraordinary accuracy," explained Lior Michaeli, a postdoctoral scholar and co-lead author of the study.
To overcome challenges like heating effects from the laser, the researchers developed a custom-built interferometer to isolate and measure even the smallest vibrations caused by radiation pressure. This breakthrough allowed them to mimic real-world conditions, such as a sail being hit by a laser at an angle, and gather critical data on how the sail responds.
What’s Next?
The team’s work is only the beginning. Future research will explore how advanced materials, like nanostructured surfaces, can stabilize a lightsail and keep it aligned with the laser beam. "If a lightsail drifts or rotates out of position, we need it to correct itself automatically," said co-author Ramon Gao, a graduate student at Caltech.
The ultimate vision is to create a freely accelerating lightsail 10 square meters in size and less than 100 nanometers thick. While this first experiment involved a tethered prototype, it marks a crucial milestone in turning science fiction into reality.
The research, published in Nature Photonics on January 30, was supported by the Air Force Office of Scientific Research and the Breakthrough Starshot Initiative.
As humanity continues its quest to explore the stars, Caltech’s work on lightsails is pushing the boundaries of what’s possible, bringing us closer to unlocking the secrets of interstellar travel.
No Comment to " Caltech Researchers Take First Steps Toward Lightsail-Powered Interstellar Travel "