Sustainable futures
Transforming deep-space missions
Future spacecraft may no longer need to rely on large fuel reserves to travel through space. Researchers are developing a new generation of solar sails that harness sunlight for propulsion, potentially enabling longer, more sustainable missions while opening up new possibilities for space exploration.
The Challenge: Space exploration depends on heavy, fuel-intensive propulsion systems
Traditional spacecraft rely on onboard fuel for propulsion, which adds weight, increases mission costs and ultimately limits how far and how long a spacecraft can travel. As ambitions grow for deep-space exploration and more sustainable space technologies, researchers are looking for alternatives that can operate without carrying vast amounts of fuel.
Solar sails have long been considered a promising solution because they use sunlight for propulsion. However, conventional reflective solar sails can face challenges with manoeuvrability, stability and performance, particularly in demanding environments such as Low Earth Orbit where atmospheric drag remains a significant obstacle.
Our Approach: Using sunlight in a completely new way
Researchers from the Faculty of Engineering and the NottSpace research team have developed a new class of ultra-light propulsion technology known as transmissive solar sails. Unlike conventional sails that generate thrust by reflecting sunlight, these innovative sails bend light through microscopic refractive patterns embedded within the sail surface.
To design these next-generation sails, PhD researcher Samuel Thompson developed a sophisticated ray-tracing simulation capable of modelling how sunlight moves through the sail. He also created a reinforcement-learning optimisation system that continuously refines the sail's microscopic patterns to improve acceleration, stability and control. This approach allows sail designs to be tailored for specific missions and rapidly adapted as requirements change.
The research forms part of a wider international collaboration involving the Technical University of Munich and KTH Royal Institute of Technology. Together, the teams are exploring how these technologies could contribute to future space missions and even large-scale concepts such as planetary sunshade systems.
The Impact: Opening new possibilities for sustainable spaceflight
The study shows that transmissive solar sails can provide significant improvements in propulsion efficiency and spacecraft control. By reducing dependence on onboard fuel, the technology could enable spacecraft to operate for longer periods, travel further and undertake missions that would otherwise be impractical or prohibitively expensive.
Beyond deep-space exploration, the technology could support a wide range of future applications. The ability to optimise sails for different operating environments could improve mission flexibility, while their high performance in Low Earth Orbit could make them valuable tools for sustainable satellite operations and space debris removal. Researchers also believe the technology could contribute to ambitious future concepts such as space-based climate intervention systems that aim to manage the amount of solar radiation reaching Earth.
By demonstrating a new way to harness sunlight for propulsion, the research is helping to lay the foundations for cleaner, longer-lasting and more capable spacecraft that can explore deeper into space without relying on conventional fuel-based systems.
To read the full paper, click
"For this paper, I developed a ray tracing simulation to characterise and optimise patterned, refractive solar sails to maximise their acceleration and stability. The appeal of this approach was that the algorithm could be told to optimise according to any criteria, allowing sails to be fine-tuned for specific missions and rapidly redesigned in response to evolving requirements."
Samuel Thompson is a researcher in spacecraft propulsion and solar sail technologies, with expertise in orbital dynamics, computational modelling and optimisation. His work focuses on developing next-generation fuel-free propulsion systems that use sunlight to improve spacecraft performance, support sustainable space exploration and enable future space missions.
Dr Nishanth Pushparaj leads research in aerospace engineering and sustainable space technologies, with expertise in spacecraft dynamics, mission design, solar sail propulsion and orbital mechanics. His work focuses on developing fuel-free propulsion systems and innovative spacecraft technologies that support long-duration space missions, debris removal and future deep-space exploration
Dr Chantal Cappelletti is an Associate Professor in Space Systems and an expert in small-satellite technologies, CubeSats and spacecraft systems engineering. Her work spans spacecraft design and development, payload and platform integration, with extensive experience in international small-satellite missions and technology demonstrations.