The future of space exploration and human survival beyond Earth depends on our ability to harness local resources efficiently. Can we create catalysts in microgravity that revolutionize our approach to life support and fuel production in space?
The quest for sustainable space exploration has led to an intriguing project co-funded by ESA Discovery. Researchers at the University of Bremen are exploring whether fabricating water-splitting catalysts in microgravity can provide a more efficient and reliable solution for space missions.
The project, titled ‘Synthesis of nanocatalysts for solar energy conversion in reduced gravitational environments,’ focuses on photoelectrochemical systems. These systems combine solar energy capture with electrolysis, allowing direct water splitting using sunlight. It’s an ambitious attempt to tackle the fundamental challenge of learning to live sustainably beyond our planet.
But here’s where it gets controversial: electrolysis, a well-known process on Earth, faces a unique challenge in space. As gases form during the reaction, they create bubbles on the catalyst surface, acting as insulators and hindering the process. This is where the Bremen team’s innovative approach comes into play.
The team’s solution involves nanostructured surface designs, engineered at the molecular level with features incredibly small, thousands of times thinner than a human hair. Instead of preventing bubble formation, their system cleverly engineers specific geometries that allow gas bubbles to form and detach continuously from precise points on the catalyst surface. This prevents the insulating bubble layer from accumulating, ensuring the electrolysis process can run indefinitely.
Microgravity offers a unique advantage in catalyst manufacturing. When nanoparticles form in the absence of gravity, they achieve higher surface-to-bulk ratios and superior crystallinity compared to those made on Earth. The Bremen team utilized photoelectrodeposition, a process that uses sunlight to grow nanoparticles directly onto semiconductor surfaces, to create these catalysts in microgravity conditions, such as the Bremen Drop Tower.
Prof. Katharina Brinkert explains, “In microgravity, the only process that can make things stick together is the chemical bond.” Microgravity tests provide valuable insights and help the team understand the process, but the ultimate goal is to make it work under space conditions, ready for launch on spacecraft.
The results from microgravity tests are promising. The catalyst materials developed are at least as active as those synthesized on Earth. This technology has the potential to revolutionize not only space exploration but also energy production and storage on Earth, contributing to renewable energy efforts.
For future lunar and Mars missions, the vision is ambitious. Solar panel-like devices could directly convert sunlight and local water sources into the oxygen and fuel necessary for human survival. This represents a crucial step towards sustainable space exploration, where resources for sustaining human life can be produced locally, reducing the need for costly shipments from Earth.
This project, originating from ESA’s Open Space Innovation Platform, is a significant step towards the autonomous operations capability required for future lunar and planetary exploration. It showcases the potential for space-based solutions to some of our most pressing challenges, both on Earth and beyond.