Little time? At the end of the text there is a summary.

A little sour they are - and quite small. In addition, the shell of the "Micro Tina" is slightly thicker than other varieties. "Otherwise, they already taste like tomato," says Jens Hauslage. And the biologist must know, because he knows his way around with the "Micro Tina". Hauslage works at the German Aerospace Center (DLR) in Cologne - and, together with colleagues, he has sent Germany's highest raised bed on its way, so to speak.

Together with around 70 other larger and smaller missiles, the German research satellite "Eu: Cropis" was launched on board a "Falcon 9" rocket from Vandenberg, California on Saturday - with exactly twelve seeds of the "Mikro Tina" tomato variety on board. In the coming year, they will first germinate under LED light at an altitude of around 600 kilometers, then grow and finally bear fruit.

For this purpose, the satellite built by DLR in Bremen has a self-contained ecosystem. In addition to the tomato plants, this also includes a filter of lava rock populated by microorganisms as well as a liquid-filled container of algae.

Cost-effective and delicious supply - arguments for the greenhouse in space

The experiment is intended to help solve the following problem, at least in part: If humans fly back to the moon in a few years' time, as planned by US President Donald Trump for NASA, then perhaps later on to Mars, they will have to think very carefully, what they take there. Because every kilo that has to be brought into space from the Earth costs about ten thousand dollars in transportation costs. Since it would be quite convenient if the spacers could produce at least a part of their supplies themselves.

Potato, for example, wheat and soy. Or just tomatoes.

So the idea of ​​a greenhouse in space comes into play, in which such vegetables would have to be grown. For astronauts, that would not only be practical because they would have to take less food with them. The fresh produce should simply taste better than the ready meals, the spacers otherwise have to resort.

Test in the Antarctic runs

In the movie "The Martian" depends on the nursery in space even from a life. As a result, space explorer Mark Watney, left behind on the Red Planet, grows potatoes in a substrate of Marsand and fecal matter to extend his extremely scarce food supply.

Foscher Hauslage says he never saw the movie. I just never surrendered. And besides, urine is much more useful for plant breeding than solid feces anyway. But only by the way.

One could say anyway: The "Martian", that's just fiction.

On the one hand.

On the other hand, DLR is already trying out vegetable cultivation under extreme conditions in practice. So far, however, not in space, but at the German research station "Neumayer III" in the Antarctic. The crew there can now look forward to several kilograms of fresh produce per week, grown in a greenhouse without any soil, but under artificial light.

DPA

DLR employee Paul Zabel in the Antarctic greenhouse (archive image)

Growth with less gravity - can that work?

For example, in the project called "Eden ISS", researchers are learning how to control the lighting and irrigation systems to get the best return. For "EU: Cropis", however, the size of the crop is not important, the All-tomatoes will never eat anyone. Rather, the scientists want to find out how plants actually grow when they suddenly lack the gravity of the earth - and if no gardener can boost their growth with fertilizer.

Instead, this job is to take over the microorganisms in the satellite. And if that works out, experiments like "Eden ISS" can profit from that again.

Plants in space - it's not that such experiments have not already been done. On the International Space Station, for example, astronauts have germinated the white-flowered herb Acker-Schmalwand, orange zinnias bloomed - and even salad grew in weightlessness.

But not all attempts were always smooth. Among other things, there were problems with waterlogging, in which astronauts had to intervene as a space gardener to save the plants at all.

On the other hand, with "EU: Cropis" no one can bring any plants that may be weakening back on track. That's a difference. The other: Unlike the experiments on the space station, the tomatoes on board the satellite are not expected to grow entirely without the effect of gravity - but at much lower levels than on Earth. "Plants only need a tenth of the earth's gravity to know where it's up and down," says Hauslage.

Rotation around its own axis

Gravitation can not be created artificially - but it can be simulated. Based on this principle are many designs of past spacecraft visionaries for Life to All stations. People like Wernher von Braun dreamed of huge, spinning wheels that thousands of people were supposed to live in. In the interior of such a wheel centrifugal forces occur, which equal in their effect of gravity.

Anyone who has ever been squeezed into his seat with power on a chain carousel knows the principle - and "Eu: Cropis" also uses it as probably the first satellite ever. For moon conditions (0.16-fold earth gravity) it rotates 20 times per minute on its own axis, in the first half year after the start should be so. Then Mars is simulated once again (0.38 times earth gravity), during which time the flying greenhouse rotates around itself 32 times per minute. For rotation, it uses the magnetic field of the earth from which it is based repels with the help of an electric coil.

For the moon experiment, only half of the seeds are supplied with water and fertilizer, then the other for the Mars experiment. But where does water and fertilizer come from?

Simulated urine

The most important ingredient is urine, but not genuine, but from a previously mixed mixture. No one is aboard the satellite who could deliver peephole. And the participating researchers did not want to use their own urine - because there might be drug residues in there that could influence the experiment.

In any case, the simulated urine supplies the water used to irrigate the plants - and later, once it has evaporated, it can be recovered. But it also contains urea, which decomposes in a further step to ammonia. And this in turn is transformed in a filter of lava stones of countless on the surface living microbes first in nitrite and later in nitrate - and finished is usable for the plants fertilizer.

"The biofilter helps us imitate the earth," says Hauslage. However, if the filter does not work, researchers have installed a backup. This consists of a solution of small unicellular organisms, so-called green algae. Conveniently, they can not only produce oxygen to start the experiment, but also free the system of too much ammonia in the event of a problem.

What is clear: The flying greenhouse is a start for plant breeding in space, but a very small one. According to researchers, around 100 square meters of acreage would be needed to feed people. Pro Astronaut.

In short : In the interior of the German satellite "Eu: Cropis", researchers want to breed tomatoes in space in the coming months - under conditions of gravity prevailing on the Moon and Mars. The satellite revolves around itself, simulating gravity. The findings are intended to help astronauts one day grow their own food in space.