Spirulina Farming on Mars - an Alternative Food Source for Mars Colonies?

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High School Student Research Touts Benefits of Spirulina

Well, they've done it again...

Last year, two high school Freshman from North Carolina, Chase Bishop and James Thompson, took on a project to re-invent how power could be produced on Mars. ​They called their project the "Dry Ice Engine".

It was simple. Original. And extremely innovative...

...and won them the grand prize​ in North Carolina's TIME program and an opportunity to represent the State at the American Academy for the Advancement of Science meeting in Boston this last spring.

(TIME - or Time 4 Real Science - is a student-led independent research and scientific discovery program in North Carolina begun in 2006 by teachers ​Jennifer Williams and Mary Arnaudin that has produced some amazing work by budding young scientists that has been compared by mentoring scientists and judges as being on par with graduate work.)

In addition, both young men were inducted into the American Junior Academy of Science (AJAS). 

Lab work on spirulina photobioreactor

Great work, right? But what do you do for an encore?

Well, Chase, now a sophomore and with a new research partner, Alex Eberhardt, stuck with project ideas that could benefit human settlements on Mars.

During a brainstorming session, Chase, an avid outdoorsman and devout Christian whoe dreams of playing college football, hit on the idea of possibly using algae as a food source for future Mars colonies.  Alex, a long-time friend and US military history buff, jumped on board.

Together, these two high-schoolers planned a project they thought could fundamentally shift the way we think about food and how it can be grown.

After some initial research, however, they decided not to use just any algae. Instead, they opted for Spirulina.

Spirulina, which is often referred to as blue-green algae due to its color, isn't technically an alga at all. It's a cyanobacterium - a type of bacteria that get's it's energy through photosynthesis like algae and other plant life.  

It's also a plant that has an extremely high protein content, though, making it a 'super-food' in many nutritionists' minds.  So after a bit of initial research, this pair of high school sophomores decided to study whether spirulina would be an effective food source for colonists on Mars.

But they added a little twist...

With some prodding from a teacher, they decided to grow the spirulina in simulated martian soil and hydrate it with simulated urine.

Yep - you read that right - urine.

The Idea

The idea is a simple one.

Water is a rare commodity on Mars. Although there is plenty of evidence that water is available, it will always be in short supply - at least compared to Earth.

spirulina water usage for 1 pound protein

Water Requirements for 1 pound of protein

And growing food takes a lot of water.

So what is the best food source for a growing Mars colony? Potatoes?

Not quite.

When you compare the amount of water various food types need to produce one pound of protein, you find that many vegetables will produces much more prtein than meats or dairy. It's one reason many believe Martian colonists will be vegans.

And spirulina produces even more protein per gallon of water than most plants and vegetables, making it an incredibly efficient food source.

Determining a possible food source is just one step of the process, however.  You also need to determine how best to cultivate it.​

RELATED: Farming on Mars - What the First Settlers Will Need to Know

That's where the use of martian soil - or regolith, as it is referred to more often since 'soil' implies a certain amount of biomass. - comes in.

​The first people to go to Mars will undoubtedly take all of their food with them. But to build a large, sustainable settlement, food production will have to be introduced on a large scale. That means you need to grow your plants in the dirt.

Sure, hydroponics is a great alternative, but with water so scarce on Mars, is it feasible?  After all, extraction, filtering and refinement of martian water sources is all hypothetical right now. Which means depending on a local water source is not a prudent first step for a farm on Mars.

And supplying clean, potable water from Earth is not a long term option. Just look at the International Space Station.  

For years, NASA has understood that water would be a major cost of resupply for the ISS.  And there is just no way to produce water in such a harsh environment. Sure you could combine the basic elements of hydrogen and oxygen and make your own water, but you still need to supply those elements.

The solution, then, for the ISS  was to develop a way to recycle the water that was already available and use it over and over again.  And efficiency demands for such a system requires that you recycle ALL the water - even urine.​

So that's what they do.  For years, Astronauts have being drinking their own urine.

But what if, instead of recycling the urine for drinking water, you use it to grow food? After all, urine has a very high concentration of the nutrients spirulina needs - nitrogen, phosphorous... Add in trace elements of zinc and iron from the martian regolith and...

An idea was born.​..

question: is spirulina  a viable food source for mars colonies

The Project

​WIth the basic question asked, the challenge now for Chase and Alex was to develop test procedures.

Other scientists have done some similar work in testing spirulina cultivation in urine, with promising results, so methods for cultivating spirulina were well known, as were methods for simulating urine.

urine simulant process

(Yes, you need to simulate the urine to ensure adequate scientific controls of your experiments - you can't just pee on the plants!)

And simulated urine has been used in other experiments​, notably by Dao-lun Feng and Zu-cheng Wu in their 2006 paper "Culture of Spirulina platensis in human urine for biomass production and O2 evolution"

No one, however, had addressed this method of cultivation for Mars colonies. For that you need Martian soil. And Mars is a long way away.

Luckily, we know the basic elemental makeup of Mars, so soil samples here on Earth that match that makeup can be used to simulate the Martian environment. There are even companies that supply those samples, making this part of the process fairly simple.

​Next, with basic elements in hand, a test procedure was developed that could test multiple samples. Those samples included varying elements of Martian soil and urine so that the differences could be gauged and optimal growth patterns determined.

Finally, the samples were put into a photobioreactor - a device  Chase and Alex constructed that could produce the heat, light, and aeration that is optimal for growing spirulina.

photobioreactor

The result?

Spirulina appears to be a great candidate for a food source for Martian colonists, even if it is only a supplement to other, more familiar types of food​.  And urine - at least diluted urine - combined with martian soil, is definitely a viable growth medium.

However, there was one 'gotcha'. All test samples that included urine had a breakdown of their cell structure​. In other words, they experienced 'lysis'.

That's not necessarily bad - it happens quite often in lab environments - but it does mean that if spirulina is ever to find its way into a martian diet, further research is needed.

Conclusion

spirulina farming conclusions

Our ability to live - and thrive - on Mars depends on our capability to use local resources to build, farm and grow.  While many people like to focus on the technological aspects of spaceflight or habitat design (they look cool, right?), there are many, many aspects of life on Mars that need to be considered and studied.

Chase, along with his research partners James and Alex, has taken those challenges head-on.

Last year, it was power. This year - food.

And the results may just help us get a little closer to actually settling the Red Planet.

Chase and Alex won First Place in this years TIME competition and will present their work at the American Academy for the Advancement of Science (AAAS) meeting in Austin, Texas next Spring.

In addition, Chase, on the right in this picture, was elected President of the North Carolina Student Academy of Science for his scientific achievements in the TIME 4 Science program.

Chase Bishop and Alex Eberhardt

Alex Eberhardt (left) and Chase Bishop

You can view Chase and Alex's project presentation here:

Feasability of Cultivating Arthrospira Platensis as a Food Source Using Mars Regolith Simulant and Urine Simulant for Mars Exploration and Colonization - Slide Presentation.​

And a PDF version of their research paper itself here:

Feasability of Cultivating Arthrospira Platensis as a Food Source Using Mars Regolith Simulant and Urine Simulant for Mars Exploration and Colonization - PDF

​Cover Image Credit: NASA

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