The Martian atmosphere does not contain oxygen, and therefore, the Martian surface cannot support human life. Astronauts staffing a mission to Mars will need an ample supply of oxygen for both their space flight and time on the Martian surface.

Currently, spacecraft take between 150-300 days to reach Mars. Furthermore, a crew deployed to Mars would have to remain on the planet until the next “launch window” (when Earth are Mars line up closest to one another). At present, NASA estimates that the total time for a Martian mission would take approximately 3 Earth years.

Given the amount of time in flight and on the planet’s surface, astronauts will need a large supply of oxygen. However, storage capacity on any space mission is limited, so it is important that astronauts have the ability to generate oxygen—both during flight and on the planet.

Plant life, through the process of photosynthesis, has the ability to use carbon dioxide and light to make food, with the by-product of this reaction being oxygen. Both light and carbon dioxide are available on the Martian surface, therefore the activity of photosynthetic organisms may be a way to generate oxygen on Mars.

Let's test the assumption that photosynthesis generates oxygen.