Solar sails edge closer to reality, but interstellar travel is another story

June 3, 2026 report Solar sails edge closer to reality, but interstellar travel is another story Paul Arnold Author Lisa Lock Scientific Editor Robert Egan Associate Editor From planetary rovers and asteroid sample return missions to the recent Artemis II flight above the far side of the moon, we are seemingly good at doing space. But our achievements still do not match many of our space dreams, science fiction or otherwise. One of the long-mentioned ways of achieving some of our ambitions for exploring the cosmos is space sails. These are large, lightweight structures that use the radiation pressure of sunlight to move. But apart from a handful of demonstration missions, including Japan's IKAROS spacecraft, the technology has still not really gotten off the ground. Sailing through the cosmos: Reality check A new study published in the journal Acta Astronautica reviews where we are with the technology, assesses the technological gaps, and points to the bottlenecks. Imperial College London engineer Debdut Sengupta and his colleagues compared three missions at different stages of development, covering different destinations. These were Solar Cruiser (which aims to use a massive solar sail to monitor space weather near Earth), Project Svarog (plans to leave the solar system by traveling close to the sun), and Breakthrough Starshot (travel to a neighboring star system). They analyzed a raft of metrics that dictate how a sail moves, including its physical area and thickness. The research team also calculated how much better our current technology needs to be to make these missions work. The study found that the challenges increase dramatically depending on the mission's destination. The closest to being achievable is Solar Cruiser, which only needs to improve by a factor of roughly two to three compared to what we can build today. The most extreme leap required is with Breakthrough Starshot. According to the paper, our engineering capabilities must improve by hundreds of times in some key areas. Overcoming hurdles So what is holding us back? The authors identified several bottlenecks, including controlling the sail's orientation in space, managing the extreme heat that builds up on the sails, and manufacturing ultra-thin yet structurally stable materials. To overcome these holdups, they make a number of suggestions, including: "Testing of high-risk components in the actual mission environment is essential for lowering the AD2 levels [a scale measuring the technical difficulty and risk of developing new technology]." The researchers also suggest collaborations across different fields. "Cross-sectoral collaboration and cross-pollination between different types of space sails as well as other technologies emerges as a key for reducing risk." Written for you by our author Paul Arnold, edited by Lisa Lock, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you. Publication details Debdut Sengupta et al, From interplanetary to interstellar: Current status of exploration using space sails and required developments, Acta Astronautica (2026). DOI: 10.1016/j.actaastro.2026.02.036 Journal information: Acta Astronautica © 2026 Science X Network