Nasa astronauts grow chili peppers on International Space Station that will help ‘successfully send people to Mars’

Astronauts on the International Space Station are growing red and green chili peppers, the first time that the fruit have been grown on the spacecraft.

Nasa said the project, which uses Hatch chile pepper seeds, was iniatied by Shane Kimbrough – a flight engineer who grew and ate the ‘Outredgeous’ romaine lettuce.

A team with Kennedy Space Center’s Exploration Research and Technology programs planted the chili seed in a ‘science carrier’, a device that slots into Advanced Plant Habitat (APH). The APH uses LED lights and a porous clay substrate (where an organism lives in the soil) that releases fertiliser at controlled times to deliver water, nutrients and oxygen.

“The APH is the largest plant growth facility on the space station and has 180 sensors and controls for monitoring plant growth and the environment,” said Nicole Dufour, a project manager for the experiment. “It is a diverse growth chamber, and it allows us to help control the experiment from Kennedy, reducing the time astronauts spend tending to the crops.”

The APH is one of three plant growth chambers in the orbiting laboratory, which has previously been used to grow cabbage and mustard. If the mission is successful, another crop will be added in order to supplement astronauts’ diets for future missions.

Before then, the peppers will have to grow for four months on the station before they are harvested. Some of the peppers will be eaten by the crew, while the rest will be sent back to Earth for analysis – assuming that they are indeed safe to consume. The combination of microgravity, light quality, temperature, and rootzone moisture could all affect the flavour, and it is as yet unclear how the fruit will develop.

“It is one of the most complex plant experiments on the station to date because of the long germination and growing times,” said Matt Romeyn, principal investigator for the experiment.

“We have previously tested flowering to increase the chance for a successful harvest because astronauts will have to pollinate the peppers to grow fruit.”

Choosing the peppers was not an easy task; researchers spent two years evaluating over 24 varieties from around the world.

“The challenge is the ability to feed crews in low-Earth orbit, and then to sustain explorers during future missions beyond low-Earth orbit to destinations including the Moon, as part of the Artemis program, and eventually to Mars,” Romeyn said. “We are limited to crops that don’t need storage, or extensive processing.”

In space crew members can lose their sense of taste and smell as a side effect of constant microgravity, and so may prefer spicy or flavourful foods. “Growing colourful vegetables in space can have long-term benefits for physical and psychological health,” Romeyn continued. “We are discovering that growing plants and vegetables with colours and smells helps to improve astronauts’ well-being.”

Space-grown peppers are not the strangest food that astronauts may have to eat, if humanity is going to leave the planet for longer journeys such as the trip to settle on Mars; scientists also developed a method of converting human waste into a ‘Marmite-like’ protein and fat-rich substance that spacefarers could subside on.

“We envisioned and tested the concept of simultaneously treating astronauts’ waste with microbes while producing a biomass that is edible either directly or indirectly, depending on safety concerns,” said Professor Christopher House at the time.

In March 2021, scientists identified a new bacterial strain that could potentially support plant growth in space by developing a “fuel” that could keep the flora sustained under the stressful environments – something that could be necessary due to the degrading quality of pre-packaged food over long amounts of time.

“The food astronauts eat needs to be as good as the rest of their equipment”, said LaShelle Spencer, the chili pepper experiment’s project science team lead. “To successfully send people to Mars and bring them back to Earth, we will not only require the most nutritious foods, but the best tasting ones as well.”