Lightsails for star travel sound like the stuff of science fiction. But researchers at Caltech have been studying the properties of potential lightsails in the lab.
The post Lightsails, and the audacious plan to reach the stars first appeared on EarthSky.
Caltech published this article – written by Kimm Fesenmaier – on January 31, 2025. Edits by EarthSky. Lightsails to the stars The idea of traveling through interstellar space using spacecraft propelled by ultrathin sails might sound like the stuff of sci-fi novels. But in fact, a program started in 2016 by Stephen Hawking and Yuri Milner known as the Breakthrough Starshot Initiative has been exploring the idea. The concept is to use lasers to propel miniature space probes attached to "lightsails" to reach ultrafast speeds and eventually our nearest star system, Alpha Centauri. Caltech said on January 31, 2025, that it is leading the worldwide community working toward achieving this audacious goal. Harry Atwater of Caltech explained: The lightsail will travel faster than any previous spacecraft, with potential to eventually open interstellar distances to direct spacecraft exploration that are now only accessible by remote observation. The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Get yours today! Ultrathin membranes Now, Atwater and his colleagues at Caltech have developed a platform for characterizing the ultrathin membranes that could one day be used to make these lightsails. Their test platform includes a way to measure the force that lasers exert on the sails and that will be used to send the spacecraft hurtling through space. The team's experiments mark the first step in moving from theoretical proposals and designs of lightsails to actual observations and measurements of the key concepts and potential materials. Atwater said: There are numerous challenges involved in developing a membrane that could ultimately be used as lightsail. It needs to withstand heat, hold its shape under pressure, and ride stably along the axis of a laser beam. But before we can begin building such a sail, we need to understand how the materials respond to radiation pressure from lasers. We wanted to know if we could…