Enabling & Support
17/12/2025
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Solar panels work best when they face directly towards the Sun, but as the Sun moves across the sky, fixed panels lose efficiency. On Earth, motorised solar trackers adjust panel angles throughout the day, but these systems require power, maintenance, and have moving parts that can fail – significant drawbacks for space applications where repair isn’t an option.
A recent ESA Discovery project led by the Université de Bretagne Sud has developed an autonomous solar tracker that requires no motors, no electricity, and no human intervention. Instead, it uses 4D-printed materials that change shape in response to temperature and solar radiation, passively adjusting solar panel orientation as environmental conditions change.
Turning harsh conditions into opportunities
“Our activity with ESA Discovery has pioneered the idea of innovative material that are able to change shape without any human energy, with only environmental variation,” says Principal Investigator Prof. Antoine Le Duigou from the Université de Bretagne Sud. “Engineers are used to dealing with the harsh space environment. In this project, based on biomimicry and 4D printing, we turn this challenge into an opportunity!”
The ‘Biologically inspired autonomous solar tracker made with 4D printed shape-changing architectured composite materials for lunar environment’ project drew inspiration from how sunflowers track the Sun’s movement throughout the day. The team designed composite materials made with continuous basalt fibres – chosen because basalt is abundant in lunar regolith and could potentially be sourced locally on the Moon – that morph their shape when exposed to changes in temperature and radiation.
By embedding this shape-changing function directly into the material’s architecture through 4D printing, the structure autonomously controls the inclination of a platform carrying solar panels. As solar radiation and temperature vary throughout the lunar day, the material responds, improving solar panel yield without an external power source and maintenance requirements.
From nature to space: biologically inspired solar tracking
Beyond expectations: pioneering technology and patent protection
The project’s outcomes exceeded initial expectations, leading to significant technological breakthroughs and intellectual property protection.
“The outcome of this activity has been beyond expectation,” says Ugo Lafont, ESA lead on the project. “The concept that has been studied from both an academic perspective and a space relevant applicable technology led to an ESA Patent.”
To achieve the project’s ambitious aims, the team developed several pioneering technologies in composite additive manufacturing, most notably “rotoprinting” – a novel 4D printing technique that builds tubular and helicoidal structures with embedded shape-changing capabilities. This rotative technology resembles filament winding but creates structures whose morphing behaviour is programmed directly into their architecture during fabrication.
Passive solar tracking with 4D printed metamaterials
The autonomous solar tracker changes shape in response to environmental conditions, without any motors or external power.
Credit: A le Duigou/ Adrien Simon within Bionics Group
The research resulted in a high-impact publication in Advanced Materials Technologies and demonstrated working prototypes at laboratory scale, advancing the concept’s technology readiness level significantly.
Sustainability through simplification
“The field of 4D printing is quite young but very promising in many aspects,” says Lafont. “Indeed, this technology and derived concepts can be seen as contributing to sustainability due to their positive impact on space system simplification and autonomy – fully in line with ESA’s sustainable ambition.”
The passive solar tracker concept aligns with circular economy principles for space exploration. Basalt fibres can potentially be extracted from lunar regolith, structures can be manufactured on-site using 4D printing with robotic arms, the materials respond intelligently to their environment, and reduced assembly means fewer maintenance issues. At end of life, the structures could be recycled for other applications.
From Moon to Earth – and back again
The activity has catalysed new research directions and commercial opportunities. The Université de Bretagne Sud has established a joint laboratory with Coriolis Composites, a leading robotic arm manufacturer, to explore scaling the technology from one-metre laboratory prototypes to structures several metres high.
“We were the first researchers to conduct such ‘out of the box’ multidisciplinary research,” says Le Duigou. “Our activity has led to developing novel research insights that were disseminated through A-ranked publications. For the first time, we also published a patent on autonomous tubular adaptive composite structures.”
The team has developed terrestrial versions using local natural fibres instead of basalt, creating Earth-based applications from space-inspired technology. Further ESA funding proposals are in development to advance the concept toward practical implementation.
The project idea was submitted through ESA’s Open Space Innovation Platform, seeking out promising new ideas for space research, and was funded by the Discovery element of ESA’s Basic Activities.
Reference:
A. Le Duigou, M. Grabow, F. Scarpa, J. Deschamps, C. Combescure, K. Labstie, J. Dirrenberger, M. Castro, U. Lafont, Bioinspired 4D Printed Tubular/Helicoidal Shape Changing Metacomposites for Programmable Structural Morphing. Adv. Mater. Technol. 2024, 2400237. https://doi.org/10.1002/admt.202400237
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