[Global] In a recent Hollywood movie “The Martian”, the main character, astronaut (also a botanist) Mark Watney (played by actor Matt Damon), was stuck on Mars and must rely on his own super-science knowledge to survive. Struggling to survive, he calculated the amount of food (calories) he would need until a rescue mission could arrive, which might probably take a few years time.

In Mars’ atmosphere, there is 95% carbon dioxide, Watney was living in a 90-square-meter canvas structure, or ”Hab,” that provided shelter against Mars’ extreme temperatures. As long as Watney stayed in the Hab or wore his spacesuit outside of it, he had oxygen.

Although Watney had enough freeze-dried food to last slightly more than a year, he knew that won’t be enough. This is because the rescue team from Earth would take more than a year to arrive.

Watney searched all over the station and found real potatoes. Yes, he planned to grow more potatoes. He then dug up the soil of Mars as media and unpacked the poop of crew team as fertilizer. Watney also made about 600 L of water out of the chemical reaction of hydrazine and carbon dioxide.

He calculated the total amount of calories that he would need to survive, the amount of potatoes as seed plant, and the amount of formable land he would need to develop for his potato crop.

The question is, why potato? Is potato the best food source on Mars? If Watney had other choice, would he still choose potato?

A recent work has proven that lettuces can be grown in the international space station (See – Lettuces now, what next – Could astronauts get all their oxygen and food from algae or plants?) Think about the other possibilities. Algae?

Now, if Watney were able to grow algae, say Spirulina, what would be the quantity of Spirulina he need in order to survive for 400 days?

First of all, let’s see the nutritional values of potatos and Spirulina.

The calories that Spirulina carries is almost 3.75 times higher than potato. This also means that Watney would need lesser amount of Spirulina biomass compared to potatoes, in order to meet minimum daily calories of 1,500 calories per day.

Here are Watney’s transcripts:

“My best bet for making calories is potatoes. They grow prolifically and have a reasonable caloric content (770 calories per kilogram). I’m pretty sure the ones I have will germinate.” “Problem is, I can’t grow enough of them. In 62.5 square meters, I could grow maybe 150 kilograms of potatoes in 400 days (the time I have before running out of food). That’s a grand total of 115,500 calories, a sustainable average of 288 calories per day.” “To be viable, soil needs 40 L of water per cubic meter. My overall plan calls for 9.2 cubic meters of soil. So I’ll eventually need 368 litres of water to feed it.” “With my height and weight, if I’m willing to starve a little, I need 1,500 calories per day.”

In the movie, Watney figured out the maths for growing potatoes.

To summarize the maths in a sentence – Watney wanted to produce 150 kg of potatoes (115,500 calories) in 400 days on 62.5 m2 of land using 368 L of water and feces.

Let’s see what we do we need in order to produce the same amount of energy (115,500 calories) for Watney to survive with Spirulina.

Since every 100 g of Spirulina already contain 290 calories of energy, Watney would require only slightly less than 100 g of Spirulina per day in order to meet sustainable average of 288 calories per day that potatoes give. This is equivalent to about 40 kg of Spirulina in 400 days.

Quest – Rescue Matt Damon

Algae World News hereby open a quest for our readers to help Matt Damon (Watney) to achieve his target – production of 40 kg of Spirulina in 400 days on 62.5m2 of space using minimal amount of resources available on Mars. For your reference, please do include the following information in your proposal:

The type of your system (i.e. raceways, PBR, plastic bags, etc). The total amount of water needed. Source of fertilizer. Your Spirulina growth rate (in terms of g/m2/day) and doubling time and your math calculation. Area of land needed (in terms of m2). Other energy requirements (i.e. energy to for paddle wheels, aeration, etc.) Materials needed (i.e. plastic linings, concrete, glasswares, containers, etc).

Do not send email to me. Leave your answer in the comment column below this article. Let everyone see your proposal. Prize will be given to the best answer.

Exclusively reported by Algae World News