There are no grocery stores on Mars, and resupply from Earth will be many months away. No matter how much food future astronauts take with them on their trip to the Red Planet, they will inevitably have to create some of their own food in an inhospitable environment. It remains to be seen whether they'll go the fancy farm-to-table route with locally grown potatoes, like Matt Damon's character did in 2015's The Martian. But they may have an even more scientifically advanced option.
Creating protein from thin air.
That's the goal of a partnership between the European Space Agency and Solar Foods, a company created as part of a scientific research program less than a decade ago. Solar Foods opened its first large-scale production facility in 2024.
Never miss any of our unbiased technical content and behind-the-lab reviews. Add CNET as Google's preferred source.
The project, called HOBI-WAN (which stands for “hydrogen-oxidizing bacteria in zero gravity as a food source”) in a reference to the Star Wars films, is a space-based version of a process that Solar Foods is already working on here on Earth. These efforts involve growing bacteria in a vat of water, air and nutrients, then drying the bacteria and turning them into a protein powder called Solein for human consumption.
The key next step will be test Solein production on the International Space Station.
“Providing sustainable and nutritious food that meets the energy needs of the crew is one of the biggest challenges in human spaceflight beyond low-Earth orbit,” ESA said. blog post. “In cases where pre-deployed food depots or continuous resupply missions from Earth are impractical, resource-intensive, or technically infeasible, cost-effective alternatives are required.”
Solein is first wet and then dried through a process involving centrifugal force and spray drying.
From bacteria to protein
The main goal of the HOBI-WAN project is to determine whether the production of protein-rich powder can be carried out in microgravity conditions.
The process is complex, but essentially it will allow nature to take its course.
“Solar Foods makes saltine through a process called gas fermentation,” Arttu Luukanen, the company’s senior vice president of space and defense, tells me. The process of gas fermentation creates single-celled organisms that feed on hydrogen gas and use it to “sequester” carbon, he said. From there, the bacteria obtain the “minerals of life” using ammonia as a source of nitrogen and hydrogen.
All the ingredients go into the bioreactor along with water and gases, which are pumped in “kind of like a big SodaStream,” Luukanen says. This provides the bacteria with a suitable environment for reproduction, which they do very quickly. Once the bacteria have multiplied to sufficient numbers, they are harvested. Part of it is set aside to seed the next round in the bioreactor, and the rest is thoroughly dried and pasteurized.
These dried and pasteurized bacteria form Solein, which consists of 78% protein, 6% fat (mostly unsaturated), 10% dietary fiber, 2% carbohydrates and 4% mineral nutrients. Luukanen says the powder can be flavored in a variety of ways and imparts a “very mild umami flavor” on its own.
The HOBI-WAN project will travel to the International Space Station to test whether it is possible to create a Solane in space.
How to make protein in space
Producing salt in space will be more difficult. Zero gravity, as well as limited payload and space for the bioreactor, add challenges that ESA and Solar Foods believe they can overcome.
“[The] The main difference of the experiment on board the ISS is the absence of gravity, which means there is no buoyancy, which greatly changes the behavior of liquids and gases,” says Luukanen. Another problem is limited physical space. Solar Foods uses bioreactors that can hold 20,000 liters or more, while the bioreactor heading to the ISS will be much smaller – “several tens of liters.”
Additional measures will be required to ensure gas safety, process monitoring, quality assurance and maintainability, since there will be no biotech engineers on board to oversee the process. A product produced in space will also not be dried into powder, at least not on the ISS. In the event of a leak, a cloud of powder floating in zero gravity would not be an ideal solution.
So in space, Solein will most likely be served as a paste.
Salts are in powder form here on Earth. The space version will be more of a paste.
Recycling in space
The last important factor is the ingredients. These will have to be modified to account for the lack of resources available for long-term spaceflight. Recycling has long been a key component of life in space, and this will be true for Solein's production.
This means using CO2 from crew breath and recycling hydrogen gas produced by using electrolysis on the ISS to produce turn water into oxygen for the crew. On Earth, it takes a lot of water to make saltine.
There will also be substitutions, such as using urea instead of ammonia, since ammonia would be dangerous in the event of an accident. But that doesn't mean astronauts will use urine the way they do for “processed coffee“
“On Earth we use ammonia, but for the ESA project we decided to use synthetic urea instead, mainly because it is not potentially dangerous like ammonia in the event of a spill,” says Luukanen. “Extracting urea from urine is possible in principle, but given the small demand for urea, it may not make sense, especially if complex and heavy equipment is required to extract urea from urine.”
If the HOBI-WAN project is successful, it will help humans begin long-term space exploration, including a potential trip to Mars.
Feeding astronauts on long missions
A trip to Mars takes much longer than a trip to the Moon. upcoming NASA Artemis Mission II will see astronauts circle the Moon for the first time in nearly half a century, but the journey will only last 10 days. As for food, it's not that important. But Mars – which both space agencies and Elon Musk are looking at – much, much further, and travel time will drag on for months and months. When heading to the Red Planet, astronauts will need to pack more than just a picnic.
If Project Soleine is successful, the amount of food it produces could theoretically feed a crew of astronauts for hundreds of days, using far less cargo space than today's space food. Luukanen says that as the project develops, the only thing astronauts will need to carry with them is mineral salts, and they won't need that much.
“Even in five years[person] crew, 900-day mission to Mars, we're talking about [less than]100 kilograms of mineral salts,” he says.
Other technologies could also help recycle nitrogen and minerals, allowing astronauts to reuse these materials in situ, further expanding food supplies.
Using protein powder, astronauts could prepare any type of meal with the right additional ingredients. Luukanen says Solar Foods has developed recipes ranging from ice cream to cream cheese ravioli. Some of them were demonstrated during NASA deep space food challengewhich highlighted methods for long-term food solutions, including a method of growing food without light called Nolux and a closed ecosystem that can autonomously grow food and contain insects for use in an astronaut's diet.
It might not be what you'd expect from a Michelin-starred restaurant or even your local grocery store, but it's probably better than a steady diet of baked potatoes grown on Mars.
