The Melissa team is working to recycle water and oxygen on the International Space Station to decrease the number of restock missions by experimenting with hardy organisms like spirulina algae.
Recycling is incredibly important in space. It can take up to eight vessels of oxygen, water, and food per year to provide for the six astronauts on theåÊInternational Space StationåÊ(ISS). For the past 25 years, theåÊMelissa teamåÊhas been working to transform carbon dioxide and waste into oxygen and water to decrease the restocks needed.
The Melissa team consists of nine independent organizations across the world researching, testing, and evaluating different phases for this goal. Using the model of Earth’s aquatic systems for this conversion, the Melissa team has focused on bacteria, algae, plants, chemicals, and physical processes (such as mechanical grinding, bioreactors, membrane filtration, and wet oxidation). The Melissa project can now recycle around 70 percent of the waste produced on ISS, and aims to increase that number.
In the next 12 months, parts of potential ecosystems will be tested on the ISS. For example, one experiment features a bio-reactor utilizing light. The organisms will take in light and carbon dioxide and hopefully produce water and oxygen. The team faces a challenge in getting organisms to thrive in space, while still being able to extract the beneficial products continuously. In other words, the closed ecosystem must be hardy enough to survive interruptions in the process.
One such hardy organism is spirulina algae. Harvested in South America and Africa for centuries, it is used in dietary supplements for its high levels of protein, iron, and minerals. This simple food also boasts high multiplication rates and can turn carbon dioxide into oxygen. This year, astronauts will test its resilience in the weightless atmosphere of the ISS. If successful, a follow-up experiment will determine if spirulina can grow on carbon dioxide in space by mimicking breathing.