For decades humans have dreamed of settling other planets. After making sufficient strides on the moon, Mars is next in line in the not all too distant future. NASA is aiming for 2035; with its “Mars One” mission, a Dutch company plans on founding the first Mars colony as early as 2025. Whoever’s first, these missions shall serve as a starting point for a permanent human presence on Mars. Since Perry Rhodan, numerous sci-fi enthusiasts have been yearning for this moment. Now that it’s approaching ever more palpably, the focus has turned to the basics, such as how Mars inhabitants are to eat. Science has been working on a solution to this for years: cultivating plant life in outer space.
Problematic from the get-go are the immense research costs associated with providing astronauts and researchers with food on other celestial bodies. A kilogram transported from Earth to the ISS costs about $20,000. Bringing the same amount to Mars – upwards of a million. Giving a space colony the means to provide for itself autonomously seems all but inevitable for such an undertaking. Along with food production, a greenhouse on the moon or Mars could also serve to treat water and produce oxygen. Not to mention improving inhabitants’ mental state; they certainly won’t be against a bit of greenery in their station
The issues facing space vegetables are manifold. Reduced or non-existent gravity can affect the growth of plants in various ways. Take irrigation for starters. In microgravity, liquids turn into floating droplets, as is prevalent aboard the ISS. They attach themselves to objects while remaining liquid. For a plant this would mean death, should its roots be continuously surrounded by liquid water. Sunlight, too, which reaches Mars at half the strength as it does the Earth, is a huge issue.
To prepare for the first wave of migration to Mars scientists tinkered with growth technologies all over the Earth in order to test them later in orbit on the ISS. One of these is the Advanced Biological Research System (ABRS). The device is a kind of high-tech greenhouse for transporting shoots and seeds to the ISS and further cultivating and examining them there. Both chambers of the ABRS can independently regulate their respective temperatures, light intensity and color as well as atmospheric composition. Plants really only need blue and red light to grow. But to make them look like those on Earth – that is, not gray or blue – green LED lights are used. Depending on programming and needs, volatile organic compounds such as CO2 and methane, can be filtered out of the air in varying degrees. Because the weight of fertile soil is too great to take on a mission of several years, plants are cultivated hydroponically. This means they grow in a highly regulated nutrient solution that prevents all contamination and deformity. What’s more, the plants grow faster and substantially larger.
One of the most remarkable experiments was conducted at ABRS in 2009. The TAGES (Transgenic Arabidopsis Gene Expression System) aided in examining root growth without gravity. Thale cress was used as the guinea pig. Before it was sent to the ISS a gene was added to its genome that fluoresces in stressful situations. When the thale cress was unhappy with its surroundings it glowed green when observed under a certain kind of blue light. In this way the astronauts were able to examine the plant’s well-being in real time without having to kill it as was usually the case. In the experiment it turned out that root growth in microgravity behaves exactly as that on Earth – a huge surprise.
In May, a new growth station reached the ISS. The very appropriately named module, VEGGIE, first tested on Earth at the Kennedy Space Center in Florida, contains a kind of fertile carpet with six individual growing pads. Embedded in the pads are seeds that will grow into heads of lettuce. They thrive in clay soil, the kind used on baseball diamonds. Under the influence of regularly dispensed manure and a fleet of LED lights, supernaturally large lettuce heads grow within a month. The machine, which looks a bit like a massive incubator, is deployed to relay to Earth at a later time whether there are microorganisms on the lettuce and whether it is fit for human consumption. If it is, a there will be a celebratory flower bed full of zinnias!
Experimentation in this vein is not only happening overseas and in outer space. This is also a task for the German scientific community. Researchers the University of Erlangen-Nuremburg are working together with the German Center for Air and Space on a greenhouse suited for growing more complex vegetables, such as tomatoes and bell peppers. Currently, experiments are underway with Micro-Tina, the strain of tomato once cultivated for this purpose. Contrary to conventional hydroponics these tomatoes grow in a nutrient solution containing single-celled algae. Artificial urine serves as manure, which the algae importantly turn into nitrate. Such a greenhouse could provide food supplies on long missions as well as eliminating astronauts’ “leftovers.” The condensed water released from the plants can be collected and used as drinking water. In 2016, the greenhouse is set to be sent into orbit on board the satellite, Eu:CROPIS (Euglena and Combined Regenerative Organic Food-Production in Space) and will be under constant observation for a year.
These gardening ambitions reveal just how important probing further into outer space is for humans. Unbridled curiosity fuels our increasingly extended trips to places farther and farther away, regardless of the obstacles. The idea of colonies on other plants probably sounds absurd and impossible for most people. Maybe it is. It wouldn’t be the first time NASA fails at its own undertakings. In five million years at the latest, the sun will obliterate the Earth. By then humanity will have to have found a new place to live. Should that not pan out by 2035, there’s still time. The groundbreaking ceremony, however, has already been scheduled.