Will humanity one day set foot on the planet Mars? Impossible to say today, but the American Space Agency (Nasa) has a plan. Its first part will begin at the end of 2024 at the earliest, when the first elements of the Gateway space station will be sent into orbit around the Moon. This replacement for the International Space Station (ISS) will allow astronauts to regularly set foot on the star Selene, but also to test new equipment and train for a potential future mission to Mars. The challenges to be met by then remain gigantic and among them, food.
Today, food for ISS astronauts is mainly provided by NASA and the Russian agency Roscosmos. “They mainly prepare tin cans to be reheated, while Americans prefer freeze-dried dishes – to be rehydrated with water – or heat-stabilized, even irradiated by ionizing rays”, explains Alain Maillet, expert in space nutrition and at the Medes team from the French space agency (CNES). Even if the quantities are small, fresh products are regularly brought in by suppliers, in particular to boost the morale of the teams. True to its reputation as a country of gastronomy, France is also taking part in the effort and regularly prepares dishes for ISS. And not just any. “Since 2009, we have been offering event meals – birthdays, parties – which take place on average once or twice a month, in collaboration with the great chef Alain Ducasse, continues the specialist. The feedback from the astronauts is excellent and the psychological support is real “.
Surviving in space is five kilos a day, per person
Feeding astronauts on the ISS does not represent any major difficulty. But what will happen during long flights that cannot take advantage of terrestrial supplies, for example during a trip to Mars? Two scenarios are considered. In the first, the mission would last about two and a half years, including a year aboard a ship and a year and a half on the surface. The second scenario, which for the moment wins the preference of NASA, would last 1.5 years in all, including 30 days only on the red planet. But in both cases, the weight of the food is a major problem.
The two scenarios for space travel to Mars. In blue the outward journey, in yellow the time spent on Mars, in red the return journey.
Nasa
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NASA recently demonstrated that foods retain their nutritional value for three years at best. If the astronauts take all their food with them, that won’t be a problem. “Except that the main difficulty of a long-term mission is to reduce the onboard masses,” notes Christophe Lasseur, head of the MELiSSA autonomous ecosystem project at the European Space Agency (ESA). Between the equipment, the water, the oxygen, and the food, it is necessary to count five kilos per day and per person. For a 500-day mission, it’s 2.5 tons per astronaut minimum”.
100% recycling objective
The (very) American options envision either building bigger, more powerful rockets carrying more food, or sending some of the food into motherships that will be stationed in Mars orbit waiting for the astronauts. In the latter case, the question of perishability could arise. “But research is underway to go beyond the three-year stage”, specifies Alain Maillet. Europe, for its part, is campaigning for a “responsible” approach, with a fully autonomous vessel thanks to a circular economy making it possible to get as close as possible to a spatial Holy Grail: 100% recycling. “The challenge: transforming all waste into water, food and oxygen. Achieving 80% recycling of all resources within thirty years seems realistic to us. If we succeed, it’s won,” says Christophe Lasseur.
One of the current leads concerns packaging. A work that began in particular after the first space mission of the Frenchman Thomas Pesquet, who then suggested creating reusable packaging. “We first worked with a Breton company to produce protective foams from bacterial synthesis rather than petroleum-based products, explains Alain Maillet. And they proved to be just as resistant”. In the future, they could be used as compost, or as material for 3D printers. “Thomas then told us: it’s good, but it would be even better if they were edible,” he continues. French engineers then designed packaging made up partly of biscuits. “They were tested on board the space station during Thomas Pesquet’s last mission, adds the CNES expert. The astronauts were forbidden to eat them, because we first wanted to check their food safety, the experiment was a success. In the future, they will try to produce 100% edible packaging. For the moment, their resistance leaves something to be desired.
The edible packaging kit developed in Toulouse for Thomas Pesquet’s mission aboard the ISS.
CNES
Embedded agriculture is another option, especially since growing a living organism in a space where life has not yet arrived could provide excellent psychological support. “The difficulty is, in fact, to feed plants – nutrients, water, CO2 -, but taking all this would be less effective than taking food”, tempers Christophe Lasseur. We should succeed in creating a highly efficient circular economy where nothing is lost and everything is transformed. That’s good, the CO2 useful to plants is naturally produced by astronauts. For water and nutrients, it’s another matter. Some of it could come from the excrement and urine of the crew, as well as other waste such as shampoo, even packaging… Provided that the waste processing equipment does not weigh too much!
What would be the ideal plants? “At MELiSSA, we evaluate them according to several criteria: nutritional needs, energy quality, edible mass, potential of the inedible part, growth and maintenance time, etc.” explains the project manager. Scientists leave no detail to chance and compare all fruits and vegetables with each other. They precisely measure their consumption of carbon and nitrogen, but also those of all other elements such as calcium or iron, even if it is very small. Everything is calculated to the nearest gram, in order to determine what type of waste can be recycled to feed them and when, since the needs of plants evolve during the different growth phases.
Space technologies useful for the Earth
Like NASA, the ESA carries out research on potatoes in particular. The European agency will soon bring to the ISS the Precursor of a Food Production Unit (PFPU), a regenerative bio-micro greenhouse particularly suited to a circular economy. “Microalgae are also very interesting, because they produce a lot of protein – unlike many vegetables – while consuming CO2 and producing oxygen”, indicates Christophe Lasseur. Ideally, the researchers are therefore trying to create the smallest possible microalgae pools while illuminating them as much as possible. ESA has already launched projects in collaboration with French universities (Clermont-Ferrand, Nantes) to design a fiber optic system capable of capturing sunlight from outside a spacecraft (or base lunar or Martian) in order to redirect it directly above the microalgae. In the meantime, MELiSSA photobioreactor tanks have already been tested on ISS.
ESA astronaut Thomas Pesquet helps grow peppers on the ISS
ESA/NASA
If these various agricultural projects succeed, astronauts traveling to Mars will be able to eat their reserves and produce part of their food on the way. And why not prepare meals combining the two? CNES is developing a food processor capable of managing stocks and offering recipes combining different food sources. “Our prototype, FoodProcessorwill be sent on board the ISS by the end of 2022″, rejoices Alain Maillet.
All these technologies will obviously be used in the hypothesis of the creation of a lunar base or even, let’s dream a little, Martian. They might prove useful down here. The MELiSSA project also aims to transform its technologies for terrestrial use. Six companies have also been created for this purpose. “For example, we have installed toilets in residential buildings capable of separating faecal matter and urine, says Christophe Lasseur. At the same time, the Swiss company Vuna is working on transforming urine into fertilizer”.
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Generalized on a large scale, this technology could even help in the fight against global warming. The manufacture of one tonne of synthetic fertilizer releases approximately eight tonnes of CO2, a greenhouse gas. “Gold from urine, we produce tons and tons of it every day, recovering at least some of it would already be a big step forward”, he underlines. Could the quest for space exploration, often criticized for its futility and uselessness, finally help humanity save its climate and therefore its mother ship, the blue planet?
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