No. 113/2021

30 HUMBOLDT KOSMOS 113/2021 CLOSE UP ON RESEARCH But Verseux soon realised how difficult it is to become an astronaut. So, he studied biology to get to the bottom of the life aspect of the issue. Verseux specialised in astrobiology, which is the study of the conditions and possible forms of life in space. His doctorate contributed to the BIOMEX experiment: between 2014 and 2016 on board the International Space Station ISS, hundreds of samples of various bacteria, algae, lichens and fungi were subjected to the conditions present in space and on Mars. Amongst the most robust micro­ organisms were the bacteria Verseux was studying: cyano- bacteria, whose Anabaena genus is now swimming around in the Atmos vessels in Bremen. Cyanobacteria are most commonly known as blue- green algae that have a proclivity to cause lake ecosys- tems to collapse in summer. Various toxins accrue dur- ing their metabolism. If the concentration of blue-green algae is too extreme, they kill the life of the lake. But the substances can be used constructively, as active agents for drugs, for instance. They contain proteins and vitamins, and because they draw other nutrients from the soil and release them again, they could be used on Mars as a sub- strate for cultivating crops. And that’s not all: cyanobacte- ria also carry out photosynthesis. They bind carbon diox- ide from the air and produce oxygen instead. On Mars, this ability will be worth its weight in gold because oxygen, which is crucial for fuels and air to breathe, is extremely rare there. The air is largely composed of carbon dioxide and, to a lesser extent, nitrogen. GREAT NEW HOPE: BLUE-GREEN ALGAE So, cyanobacteria are space travel’s great new hope. And Verseux’ experiments underpin it. “It was clear that we could cultivate cyanobacteria with the substances that will be available on Mars. But now we know that it’s all much easier than we thought! We only have to change the atmo­ spheric conditions on Mars a little bit for the culture to thrive.” In the Atmos reactor in Bremen, researchers can change the pressure, temperature, light and composition of the air at will and then test the bacterial content. “We are looking for the best compromise between the precon- ditions of the Mars atmosphere and the ones that make the bacteria grow best,” says Verseux. All you need to do is increase the pressure and slightly adapt the ratio of nitro- gen to carbon dioxide. All in all, it’s no more trouble than it would be in a greenhouse on Earth. But this is not enough for Verseux. He now wants to use cyanobacteria to develop a bioregenerative life-support system. “I want to create something that works on the spot and not just in theory,” he says. But how should he acquire a realistic picture of the conditions on Mars while sitting comfortably in a well-equipped laboratory? “If I’m going to construct systems that function for astronauts onMars, I have to know what it is like to live there.” Verseux tries to acquire this knowledge in the most direct way possible: whilst still working on his doctorate, he applied to take part in NASA’s Mars simulation project HI-SEAS on Hawaii. From August 2015, he spent a whole year with five other researchers in an area of about 100 square metres in a roughly six-metre-high white dome with a diameter of some 12 metres, at a height of 2,500 metres, completely cut off in the middle of the barren volcanic landscape of Mauna Kea. “We tested all the aspects of a Mars mission – including the time lag in telecommunica- tions.” A radio signal from Mars to Earth takes between four and 24 minutes because, depending on the planet’s position, it has to cover a distance ranging from 55 mil- lion to 400 million kilometres. The HI-SEAS participants constantly had to deal with a signal delay of 20 minutes. French astrobiologist DR CYPRIEN VERSEUX is currently conducting research as a Humboldt Research Fellow at the Center of Applied Space Technol­ ogy and Microgravity (ZARM) at the University of Bremen. On Twitter, he tells his more than 12,000 followers about his research. He has blogged and written books about the time he spent on a Mars simulation on Hawaii and at a research station in the Antarctic. @CyprienVerseux