When humans dream of venturing farther into the cosmos, one massive logistical question looms: how do we keep everyone breathing and moving without constant supply runs from Earth?

Aboard China’s Tiangong space station (the name translates to Heavenly Palace), scientists just offered a glimpse of the answer. In a recent demonstration, Chinese astronauts successfully operated a system that produces oxygen and rocket fuel in orbit, mimicking the natural process of photosynthesis.

Turning Carbon Into Oxygen and Fuel

The Shenzhou-19 crew ran the experiments using artificial photosynthesis—technology that engineers the way plants convert carbon dioxide and water into oxygen and glucose. It’s a remarkably robust technology.

Astronauts used a specialized, drawer-shaped device equipped with semiconductor catalysts. Inside this compact lab, they converted carbon dioxide and water into oxygen and ethylene. That second byproduct is a big deal; ethylene can be processed into rocket propellant. While Chinese researchers began exploring extraterrestrial artificial photosynthesis back in 2015, seeing it work in orbit is a major milestone.

Digital illustration of Tiangong. Credit: China Manned Space Engineering Office.

The system operated under room temperature and normal atmospheric pressure. This is a crucial improvement because it slashes the massive energy demands usually associated with high-temperature or high-pressure chemical synthesis. According to the China Manned Space program, the process also demonstrated precise control over gas and liquid flows in microgravity, a notoriously difficult feat required for future space-based manufacturing.

“This technology mimics the natural photosynthesis process of green plants through engineered physical and chemical methods, utilizing carbon dioxide resources in confined spaces or extraterrestrial atmospheres to produce oxygen and carbon-based fuels,” explained a report from Chinese state broadcaster CCTV.

By tweaking the catalyst, researchers can produce other valuable compounds, such as methane or formic acid, which could serve as precursors for fuels or even sugars.

This capability aligns with China’s broader strategy for orbital longevity; in January 2025, the launch of the Shijian-25 satellite tested new technologies for in-orbit refueling, creating a potential future ecosystem where Tiangong produces the fuel that satellites like Shijian-25 distribute.

Why It Matters

Space agencies worldwide have long sought ways to sustain astronauts on deep-space missions. Currently, the International Space Station (ISS) relies on electrolysis, which uses electricity from solar panels to split water into hydrogen and oxygen. While effective, the method consumes significant amounts of energy. The ISS uses a third of its energy reserved for environmental control and life support systems to generate oxygen. By comparison, the artificial photosynthesis system tested on Tiangong requires far less energy, making it better suited for long-haul missions.

This aligns with a global shift toward “in-situ manufacturing.” We are moving away from the era where we have to launch every single spare part and breath of air from Earth. For instance, the European Space Agency successfully 3D-printed metal parts on the ISS for the first time earlier this year.

China is integrating this philosophy into a broader strategy for orbital longevity. In January 2025, the Shijian-25 satellite tested technologies for in-orbit refueling. When you combine that with Tiangong’s new ability to produce fuel components, you start to see a future ecosystem where the space station acts as a gas station for satellites.

With a crewed Moon landing planned before 2030, China is staking its claim as a leader in sustainable space technologies. By addressing the two biggest challenges of space travel (breathable air and propulsion) the stars are suddenly a little closer, and it’s all thanks to a humble device aboard a space station orbiting Earth.

This article was first published in January 25, 2025, and has been reedited to include additional, subsequent information.