Global food production is one of the key societal challenges of the 21st century. A growing world population with the simultaneous upheaval caused by climate change demand new methods of cultivating crops in regions with unfavourable climates. A closed greenhouse is a good way of growing food in deserts and low-temperature regions – as would be the case on missions to the Moon and Mars – as it permits harvesting regardless of the weather, the Sun and specific seasons. In a closed greenhouse, water consumption is immensely reduced and there is no need for pesticides and insecticides. This kind of model greenhouse will set off for the Antarctic at the end of 2017 for a year of long-term testing under extreme conditions as part of the EDEN ISS project. Unparalleled elsewhere in the world, this Antarctic greenhouse was presented to the public for the first time at the Bremen site of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) on 7 July 2017.
"DLR is pursuing application-oriented research within the EDEN ISS project. Its purpose is to bring fresh impetus to food production on Earth and for human space flight," says Hansjörg Dittus, DLR Executive Board Member for Space Research and Technology. "In doing so, we are advancing the cause of a key technology that will provide a fresh diet to inhabitants of climatically harsh regions – in our case the Antarctic – as well as to astronauts on future long-term missions."
A year on the eternal ice
In December 2017, DLR scientist Paul Zabel will relocate to the Antarctic with the EDEN ISS greenhouse. He will remain there for one year, during which he will be a member of the winter crew of the Neumayer III Antarctic station, which is operated by the Alfred Wegener Institute (AWI). "Cucumbers, radishes, peppers, lettuce and herbs are already growing in the test run being conducted in Bremen," says Project Coordinator Daniel Schubert from the DLR Institute of Space Systems. "By providing special artificial light, an ideal temperature and selected nutrients entirely without soil, we are able to grow our plants more quickly and with a higher yield than in their natural environment." From a practical perspective, the healthy produce and innovative technology will enrich the diet of the Neumayer III winter hermits while at the same time simulating the supply scenario of a human mission to Mars. "In addition to testing plant cultivation, we are also excited to find out how the station team responds to the fresh additions to their menu," Schubert continues. "I am sure the strawberries will be a particular delight."
Zabel is already looking forward to his extended field mission, which he believes will feel further from Germany than will actually be the case. "We will not see the Sun during the polar nights, and will be thousands of miles from home with no immediate way of returning," says Zabel. "So it does feel a bit like setting off on a journey to a distant planet."
Scientists live and work at the Neumayer III station all year round, braving the harsh Antarctic conditions. Located on the Eckström Ice Shelf in the Atlantic sector of Antarctica, the station is the base for German Antarctic research. Up to 50 people live in the station during the Antarctic summer – but it gets lonelier in winter, when only nine people remain at the base: one cook, three engineers, one doctor and four scientists. Zabel will be the tenth member of the upcoming winter crew. The Sun does not even rise above the horizon between 21 May and 22 July – during the polar night there is just a brief twilight period around noon. The lowest temperature recorded so far at the Neumayer III station was minus 50.2 degrees Celsius.
"Provisions are delivered by ship once a year around Christmas – six containers filled with approximately 60 tons of food and drink. Fruits and vegetables are stored as frozen to make them last during the long winter isolation phase," says long-standing station director Eberhard Kohlberg. Fresh fruit, vegetables and lettuce from South Africa are sent by air freight every three to four weeks in the summer season from November to February. The last rations of fresh produce arrive at the station in late February. The following months are spent without fresh lettuce, tomatoes and cucumbers. There are only a few types of fruit that keep for longer and will last until May. Potatoes and onions are the only items that can be stored for extended periods. "So the first delivery of fresh lettuce and tomatoes in November is highly anticipated," says Kohlberg.
Made in Antarctica – plant cultivation with artificial light and without soil
Aeroponics is the magic word for cultivating in an Antarctic setting, and which will be used to enrich the crew’s diet. This technique is used to cultivate plants in a sterile environment without soil by spraying them with a water/nutrient blend. The researchers also adjust the atmosphere in the greenhouse to best suit the needs of the plants. "We increase the carbon dioxide content, use special filters to clean the air of any fungal spores and bacteria, and sterilise the air with UV radiation," says Schubert. "This enables entirely organic cultivation without insecticides and pesticides." Like on a space station, the greenhouse has an airtight circulation system, including an airlock that Paul Zabel will use as his daily entrance. Moreover, the closed circuit will make it possible to recapture all of the water that the plants release into the air and reuse it.
The artificial Sun in the Antarctic night is a cocktail of blue, red and white light that bathes the containers and plants in shimmering violet hues. Light is shone on the plants in a determined day/night rhythm for 16 hours, after which they are left to rest light-free for eight hours. A water-cooled LED system, with computerised control of each individual LED and its wavelength, provides the specific conditions needed for each plant to thrive effectively.
International collaboration in EDEN ISS
The EDEN ISS project will be completed in collaboration with the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) as part of a winter mission at the German Antarctic station Neumayer III. Numerous other international partners are jointly working in a research consortium under the auspices of DLR to keep the greenhouse up and running in the Antarctic environment: Wageningen University & Research (Netherlands), Airbus Defence and Space (Germany), LIQUIFER Systems Group (Austria), National Research Council (Italy), University of Guelph (Canada), Enginsoft (Italy), Thales Alenia Space Italia (Italy), AeroCosmo (Italy), Heliospectra (Sweden), Limerick Institute of Technology (Ireland), Telespazio (Italy) and the University of Florida (USA). Project funding comes from the European Framework Programme for Research and Innovation Horizon 2020 under project number 636501.