Humankind is increasingly looking beyond its own planet as it contemplates the future. NASA’s Artemis program plans to establish a sustained human presence on the Moon from 2028, while the Russian, Chinese, and European space agencies have all expressed similar ambitions. But this represents a very small step towards the ultimate goal: colonizing Mars. This is being actively pursued by several national space agencies, as well as private organizations such as SpaceX.
One of the major challenges for any prolonged venture into outer space is providing food for astronauts. This has been the subject of considerable research by the EDEN ISS project, which was first launched by the European Union and a number of technology partners in 2015. The project’s aim is to develop procedures and technologies for safe food production on the International Space Station and beyond.
As part of its research, EDEN ISS has created a shipping-container-sized greenhouse facility to trial its technologies. After being tested in Bremen, northwest Germany, in 2017, it was shipped to the German Neumayer III research station in Antarctica, a location that mirrors the isolated and inhospitable terrain of an alien planet.
“IN THE FUTURE, A CLOSED-LOOP GREENHOUSE SUCH AS THIS COULD PROVIDE FOOD FOR ASTRONAUTS WHILE ALSO ASSISTING WITH AIR REVITALIZATION AND WATER RECYCLING, THEREBY REDUCING THE AMOUNT OF RESUPPLY NEEDED FROM EARTH.”
EDEN RESEARCH GROUP, GERMAN AEROSPACE CENTER (DLR)
The greenhouse is currently being used by NASA and the DLR for a series of joint experiments on vegetable cultivation techniques on the Moon and Mars. NASA scientist Jess Bunchek is trialing how future astronauts could grow lettuce, cucumbers, tomatoes, peppers, and herbs using as little time and energy as possible; she tends to her crop on a daily basis, putting greenhouse technologies and plant varieties to the test.
“We’re gaining a significant amount of hands-on knowledge about operational aspects such as crew demands and workload,” says Vrakking. “The procedures involved with every activity within the greenhouse need to be investigated and optimized before a greenhouse eventually begins operation on the Moon or Mars, to free up astronauts to focus on exploration and science.”
Although it may seem counterintuitive in an environment that can reach -58°F, cooling is essential for the greenhouse to function, as lighting and other electrical equipment creates heat that needs to be removed. “The cooling system is very important,” says Vrakking. “And we need to have accurate control over the amount of heat that is removed from the facility to maintain the optimum air temperature and humidity levels.”
Jan Levin, former Branch Manager of wholesalers Frigotechnik in Bremen, remembers he found it hard to believe that a customer wanted a cooling system that would work in such demanding conditions. “When they first contacted me, they said they wanted to meet in person and explain the project,” he remembers. “We went for a coffee and when they started talking about simulating weather conditions on the Moon, at first I thought they were joking.”
Levin contacted Güntner and then worked closely with the company’s technical team to find a cooling solution that would do the job. The answer was an adapted version of a Güntner Flat COMPACT Dry Cooler. It was a considerable technical challenge.
“You have to have special lubrication for the bearings on the fans and motors,” says Udo Brünjes, at that time Sales Manager at Güntner. “And that means oil or grease with high viscosity at very low temperatures, otherwise there’s a risk that the fan bearings will break. At the same time, you have to make sure the oil doesn’t become too liquid at higher temperatures, meaning it doesn’t adhere to the bearings, jamming the fans. We also needed low temperature protection for the cables and a heating system for the box containing the electronics, to avoid freezing.”
“THE EQUIPMENT ALSO HAD TO BE EXTREMELY RELIABLE… IT COSTS A LOT TO TRAVEL ALL THE WAY TO THE ANTARCTIC, SO IT WOULD HAVE BEEN VERY EXPENSIVE IF NEW PARTS OR AN UPDATE WERE REQUIRED.”
FORMER BRANCH MANAGER, FRIGOTECHNIK
The Güntner dry cooler has been operating constantly in the Antarctic without any problems for more than four years. In the future, it may not only be astronauts who benefit from the EDEN ISS research. Vrakking says that the knowledge gained could be also be used for greenhouses on Earth, especially in polar or desert areas or in places that have been devastated by natural disasters.