As we prepare for long-distance space travel and life on Mars, biotechnology could be the only possible solution to make spaceships no longer dependent on Earth’s constant supply.
“As human beings, we need a constant supply of oxygen. We need constant access to nutritious food, clean water, and a safe and clean waste disposal system,” said Italian astronaut Samantha Cristoforetti during a live stream from the International Space Station (ISS).
The ISS recycles most of the water it uses from the air and from astronaut urine, and can produce some of its oxygen from water. However, it still needs a constant supply of oxygen, water and food from Earth to keep the astronauts alive.
“But what happens if human beings want to travel further into deep space, far away from earth, where we can not rely on a constant resupply?” asked Christoforetti.
Establishing a base on the Moon or taking humans to Mars for the first time is a goal of several countries around the world — and of billionaires. Jeff Bezos is already outlining plans to set up a Moon colony, while Elon Musk aims to take us to Mars.
“To be able to survive a long-term mission, you need to transport a lot of water, a lot of food and a lot of oxygen,” Christophe Lasseur, R&D Coordinator at the European Space Agency (ESA), told me. “For the Mars mission, it would be somewhere in the order of 30 tons. Today this is too heavy for the launchers. We need to be able to recycle everything during the mission.”
All around the world, scientists are working to address these challenges. The goal is to replicate the natural recycling of resources that happens on Earth. How? With biology.
Keeping astronauts healthy
As we start taking on longer space missions, we need to confront the effects that life away from Earth has on the human body. It is well known that zero gravity makes the muscles and bones of the strongest astronauts grow weak in just 6 months.
To prevent that, astronauts keep active while in orbit, but they are still at risk of bone and muscle injuries upon their return. As we travel further into space, we will need spaceships to be equipped to heal their crew.
“Following prolonged space missions, muscle and bone wasting, inflammatory reactions and damage resulting from radiation are considered among the major challenges and threats imposed on astronauts,” said Arik Eisenkraft, Director of Homeland Defense Projects at the Israeli company Pluristem.
The company develops treatments based on placental cells to treat a wide range of diseases. Last month, Pluristem entered a collaboration with NASA to test these cell therapies as a solution to treat the medical conditions caused by space travel.
The company will first study whether the treatment can prevent damage in animals under the effects of reduced gravity. Challenges include the fact that zero gravity might alter the growth of the cells, ensuring they can be safely frozen and thawed, and developing a ‘practical’ way of administering the treatment in space.
“If [our] technology is shown to prevent and reduce these damages, this could have a tremendous impact on future space travel, allowing to preserve and enhance the health of astronauts,” Eisenkraft told me.
In the longer term, astronauts might be able to print their own tissues and organs at will. The Russian company 3D Bioprinting Solutions is the first to have 3D-printed living tissue in space. Last December, Russia’s space agency sent one of the company’s space bioprinters to the ISS. The equipment was successful in printing mouse thyroid glands and human cartilage.
Turns out that 3D-printing in space has some advantages. As it’s not restricted by gravity, it is possible to print from all sides at once, using magnetic and acoustic fields to keep the cells in place. “It looks like making a snowball,” Yusef Khesuani, co-founder of 3D Bioprinting Solutions, told me.
The bioprinter will stay at the ISS for 5 years as the company sends biological materials to experiment with space bioprinting. The next one is scheduled for this summer. “For the next steps, we want to understand the functionality of these constructs. If it’s thyroid gland tissue, we need to understand if it can produce hormones,” said Khesuani.
For now, the company will focus on creating more and more complex tissues, but restricted to the scale of just a few millimeters. In the future, growing larger tissues will require specialized bioreactors that can keep the cells alive while in orbit. Khesuani believes worldwide scientific collaborations will be needed to advance this kind of research, using the equipment of agencies like NASA, ESA and the Japan Aerospace Exploration Agency (JAXA).
Growing food in orbit
Currently, the ISS relies completely on Earth supplies for food. Growing our own food will be necessary to sustain long-distance space travel.
“We’re going to be sending more mass and more people into space than ever before,” said Richard Barker, a researcher at the University of Wisconsin-Madison. “If we’re able to grow food for them in orbit, that will make the exploration of the space environment more sustainable and accessible to more people.”
Barker is collaborating with several NASA projects that have sent and grown vegetables in space missions. In particular, he is studying how plants behave under the ‘stress of space life’. His research group has found that being in space activates plant genes that respond to heat and flooding on Earth. Identifying these genes has allowed the researchers to genetically engineer the plants so that they grow better in space.
But the ultimate goal is being able to grow plants not just onboard spaceships. China is already running tests for the construction of a self-sustained ‘Lunar Palace’ on the south pole of the Moon, while NASA — and Elon Musk — has its eye on eventually sending humans to Mars.
Much like Matt Damon in the 2015 movie ‘The Martian’, humans traveling to Mars will rely on culturing potatoes and other vegetables on the red planet. It might not be as easy as the movie makes it seem, though. As Barker pointed out, the Martian soil is too salty for plants to grow in.
His research team has been investigating a genetic engineering technology to make plants resistant to salinity and drought (you won’t find that much water on Martian soil either). The group has been conducting experiments with Arabidopsis thaliana, a cousin of the mustard plant that is a great genetic model — as Barker puts it, “it’s the lab rat of the plant world.” They are now getting ready to test whether it works with cotton, with the final goal of extending it to leafy greens such as lettuce, bok choy and Chinese cabbage.
ESA is running similar tests to grow plants and other foods in space missions. So far, it has been successful at growing algae to produce ingredients such as spirulina. The agency has also run experiments with the smaller Arabidopsis plants and is now getting ready to start growing edible plants, such as spinach, wheat, and tomatoes. The first ones will be potatoes.
In the long term, the space diet might not necessarily be restricted to vegetables and algae. In addition to its research in regenerative medicine, the Russian 3D Bioprinting Solutions plans to be the first to bioprint meat in space, something that is scheduled to happen later this year.
Many startups on Earth have taken on the challenge of producing meat without the animal — beef, pork, chicken, turkey, tuna, you name it. “From thousands of cells, you can get billions of cells,” explained Khesuani. “You wouldn’t need to send more cells from Earth.”
So far, growing complex 3D structures that replicate that of meat has proved challenging on Earth. In zero gravity, it might as well prove easier to assemble a steak while keeping the animal cells alive.
Producing clean oxygen and water
Currently, part of the oxygen at the ISS is produced through a chemical reaction to extract it from water. That requires valuable reserves of water and big equipment. On Earth, we get our oxygen from plants and other living beings through photosynthesis, so why not do the same in space?
Christophe Lasseur leads an ESA project that for the past 30 years has been investigating how to produce and recycle oxygen, water and food in space missions using biology. “We have done some flight experiments on the space station and demonstrated that we can grow algae and recycle CO2 into oxygen,” he told me. “We can control this production depending on the consumption with very good accuracy.”
The ‘Melissa’ project has proven it’s possible to recycle close to 100% of the carbon dioxide available using algae. ESA scientists have also been researching the speed at which the algae is able to grow on space as compared to Earth. The faster it grows, the fewer amounts of algae are needed to produce oxygen.
“In space, we are fighting against mass. We want everything as small and as light as possible,” explained Lasseur. “It’s a very big difference whether we need 100kg or 300kg to recycle oxygen.”
Clean water is also essential. In the ISS, up to 80% of the water is recycled from the air and from astronaut’s sweat and urine. Still, the crew relies on regular water shipments from Earth. “Water is a precious resource in space, as every crew member uses 4 to 6 liters per day, and it costs $50,000 per kilo to launch,” said Thomas Andersen, CEO Danish Aerospace Company (DAC).
The DAC is working with the Danish company Aquaporin to develop a more efficient method to purify water. Using a bacterial protein that can transport water molecules across a membrane, Aquaporin has developed a faster and more efficient method for water purification.
“In addition, [the Aquaporin membrane] can remove DSMD, a residual from plastic tubing that NASA has had an issue with removing on the International Space Station with its present recycle system,” Andersen told me. After an initial test showing the technology does work in space, DAC and Aquaporin have signed a contract with ESA to continue developing the technology further.
Finding ways of recycling all other kinds of waste is also important. “For waste recycling, bacteria are very efficient because they are very diverse and can adapt to different kinds of waste. That would be difficult to do with another technology,” said Lasseur.
The ultimate goal is to create a single life support system that can recycle everything without any external input. ESA is testing the ability of such a life-support system to indefinitely keep rats alive and comfortable, with no contact with the outside environment. The pilot plant is based in Barcelona, where Lasseur and his team will soon be showing the project to Pedro Duque — a former ESA astronaut and currently Spain’s Minister of Science.
To infinity and beyond
“The final goal is to be as independent as possible, to be able to stay for a long time in space without depending on supplies from Earth,” said Lasseur. “But achieving this goal will be progressive.”
One of the first steps towards this transition will be the construction of NASA’s ‘Deep Space Gateway’, a station that is planned to be orbiting around the Moon by 2024.
“It’s at a really exciting location because it is outside of the Earth’s Van Allen belt. That’s the protective magnetic sphere that shields us from cosmic rays and the Sun’s solar winds,” said Barker. On this station, NASA plans to build a deep space garden that will test how life copes without the Earth’s protection.
“Plants are, in my opinion, the best canary in the coal mine,” said Barker. “We’re working on robotic gardening techniques and the goal is to have a semi-automated plant growth system out there.”
These experiments will help us prepare for longer stays away from Earth, which experts predict are not that far away in time. “About 10 years from now, we’ll have the Deep Space Gateway – I’m a bit more conservative than the aerospace companies – and about 10 years after that, we’re likely to have the Moon base. In about 20 years from now Elon Musk says that we’ll able to send people to the Moon,” said Barker (adding, “we’ll see”).
What seems evident is that there is no stopping humans from traveling farther into space, and that biotechnology is the solution needed to meet all the needs of long-term space missions, and finally turn science fiction into science fact.