US space agency NASA is moving toward more deep space missions. In particular, a long-mooted mission to Mars could require at least a three-year round trip. And a growing consensus of researchers now believe algae could play a vital role in such long-term space missions.
A significant challenge for long-distance human spaceflight is the provision of the essential elements.
These include food, waste removal, radiation protection, water and oxygen.
Mars is approximately 34 million miles (55 million km) distant, requiring crews to spend years on a spaceship.
And because crews cannot carry everything with them, they will need to grow it in situ.
Recent research suggests algae could solve this conundrum of long-term space travel.
|International Space Station: Experiments involving algae have been taking place on the ISS (Image: Getty)|
|Mars Mission: Algae could play a vital role in long-term space missions (Image: Getty/SpaceX)|
NASA reveal space algae ‘key to manned Mars mission’
In a 1961 experiment, a man in Russia lived for 30 days in a room of only 4.5 cubic metres, using only algae to convert his carbon dioxide into oxygen.
After three days the potentially harmful levels of carbon monoxide stabilised and, after 12 days, so did the methane emitted by his own body.
NASA’s Space Algae experiment on the ISS last year studied the way algae grows in microgravity.
“We wanted to figure out an inexpensive way to grow algae in liquid cultures in space,” says Mark Settles, from the University of Florida, who was the principal investigator on the project.
“Algae grows fastest in liquids, but there are a series of challenges for handling liquids in microgravity.”
NASA also tested whether certain genetic variations meant algae survived better in space.
To do this, NASA created mutations by subjecting the algae to UV light, then growing each different strain for 40 generations.
“We wanted to figure out what genes are really important for algae to grow well on the Space Station” says Settles.
“We are currently characterising whether we got significantly different strains compared to doing the same experiment on Earth.”
The most promising possibility is using algae as a food source, as many types are edible.
|Algae: The green slimy stuff can provide food, radiation protection and oxygen (Image: Getty)|
|Algae: NASA has tested on many mutations of algae (Image: Getty)|
For food purposes, it’s more than likely it would be used as a nutritional supplement rather than a dietary staple” says Kevin Tyre, a payload analyst at the International Space Station, who managed NASA’s Space Algae experiment.
Getting the nutritional balance just right is a problem, too.
“Depending on the species and strains, some algae can be too high in protein and nitrogenous compounds like nucleic acids, and some can have a high percentage of cell wall material in the biomass, so you might need multiple types that are selected or engineered for a balanced food source” says Wheeler.
For radiation shielding, there is also potential. In space, astronauts are bombarded by highly energetic particles known as cosmic radiation. Finding something to block that radiation is key to helping us survive in space.
Algae grows in a liquid culture, and if the reactors are placed on the outside of the spaceship, they could be used as part of the shield to block radiation, says Settles.
“The water in the media would serve as the shielding, but the algae would need to tolerate the cosmic radiation” he says.
Developing this idea requires both technology and strain research, to find the strains of algae that are not going to be destroyed by the radiation.
Algae could also provide waste removal, too. If human waste is used as a source of food for the algae, it will recycle nutrients like phosphorus and nitrogen into a form the astronauts can then potentially eat.