A new project supported by the European Space Agency has yielded a groundbreaking solar tracker that functions without electricity, motors, or any human control. Drawing inspiration from sunflowers, researchers at the Université de Bretagne Sud have engineered a system using advanced 4D-printed materials. These smart composites autonomously change shape when exposed to varying light and heat, allowing them to passively orient solar panels for maximum efficiency. Designed with the challenging lunar environment in mind, this innovation could revolutionize power generation for space missions by removing the need for mechanical systems prone to failure.
To maximize energy generation, solar panels must directly face the sun, a task typically handled by motorized trackers. However, these systems are a liability for space missions, as they consume power, require maintenance, and contain moving parts that can break down where repairs are impossible. A recent ESA Discovery project has pioneered a passive alternative. By harnessing biomimicry and 4D printing, researchers have created a structure that turns the harsh space environment from a challenge into an asset, using its temperature and radiation fluctuations to power the device’s movement.
The core of the technology lies in composite materials made with continuous basalt fibres. This material was specifically chosen because basalt is abundant in lunar regolith, opening the door for future on-site manufacturing on the Moon. Through a novel 4D printing process, the shape-changing function is embedded directly into the material’s architecture. As the lunar day progresses and environmental conditions shift, the structure morphs on its own, tilting an attached solar panel platform to follow the sun without any external energy source.
The project’s success has surpassed initial goals, resulting in significant technological advances, including an ESA patent. To achieve this, the team developed a pioneering additive manufacturing technique called “rotoprinting,” which fabricates tubular and helical structures with pre-programmed morphing behaviors. Ugo Lafont, the ESA lead on the project, noted that the outcome was “beyond expectation” and praised the concept’s contribution to sustainability through system simplification and autonomy. Working prototypes have been successfully demonstrated at a laboratory scale, significantly advancing the technology’s readiness for practical application.
This passive solar tracker concept also aligns with circular economy principles for space exploration. Structures could potentially be manufactured on the Moon using local resources, and at the end of their life, the materials could be recycled for other uses. The research has already spurred new commercial opportunities, including a joint laboratory to scale the technology from one-meter prototypes to structures several meters high. Furthermore, the team is developing terrestrial versions using local natural fibres, demonstrating how space-inspired innovation can lead to sustainable applications on Earth.