Using roaches to minimise waste in space

On the International Space Station, astronauts typically bag their waste and store it on vehicles that either return it to Earth or burn it up in the atmosphere. While this method works for short-term missions, it could be expensive and logistically problematic on missions beyond low-Earth orbit.

Recycling waste on board is one way of mitigating these issues. Currently, astronauts on the ISS rely on high-temperature reactors to process small amounts of rubbish and break it down into oxygen and water, for example. However, the remaining waste is still sent back to our planet, contributing to space debris. To address this, Polish company Astronika has developed an insect bioreactor with funding from the Discovery element of ESA’s Basic Activities.

“The main focus of this project was the bioconversion of waste generated during space missions. We explored how insects, specifically cockroaches, could convert organic material into useful resources such as biomass in a space station. This contributes to creating a more circular and sustainable ecosystem in space.” says Nicolas Thiry, ESA engineer leading the activity.

Explaining the solution

“The insect bioreactor is an autonomous system that can handle large amounts of waste, up to 3.6 kilograms per week,” explains Mateusz Grzyb, lead engineer of the project at Astronika. “It brings several benefits simultaneously, including waste reduction, water recovery and the potential to produce protein for astronauts. No other existing device combines all these features, making it highly sustainable for space missions.”

The device offers a closed-loop system, using the natural abilities of cockroaches to process rubbish. It is also equipped with a waste grinder to fragment large pieces, if necessary. “The more insects we have, the more waste we can break down. By optimising the environment inside the bioreactor – controlling temperature, humidity, and waste conditions – we can speed up the cockroaches’ metabolism and reproduction, allowing us to effectively reduce the waste,” says Mateusz.

Why cockroaches?

Madagascar cockroaches were selected for this project due to their unique biological traits. They are hardy insects, able to survive harsh conditions and reproduce quickly. During the study, it was observed that they could complete their life cycle and maintain normal development, even on a restricted diet. These insects are also known for their adaptability to diverse environments, making them ideal candidates for controlled bioreactor environments in space.

Moreover, cockroaches are very efficient waste converters. If they digest up to 3.6 kilograms of waste per week, the roaches will produce more than 100 grams of crude protein – equivalent to over 20 eggs. As a result, they can become a reliable source of protein-rich biomass for future space missions.

To the future

“We’re still in the early stages, working at a low technology readiness level, but this project shows the concept works incredibly well,” says Nicolas.

The next step is to send a smaller bioreactor to space to test how cockroaches behave and reproduce in microgravity. Understanding how the insects react in space will provide critical feedback for further development.

In addition, researchers have also analysed how the cockroaches’ waste, or frass, can be used as a fertiliser. Eventually, the bioreactor could be used on long-duration missions to the Moon or Mars, where it could also support astronauts with plant cultivation and food production.