 Oxygen. It makes up 21% of the air around us and without it, we'd die. So how do you make oxygen in space and what do you do when your oxygen generator breaks? This is your space pod for November 10th 2016. On November 7th the ISS commander Shane Kimbrough replaced a hydrogen sensor in the oxygen generation system or OGS. The OGS was taken offline due to a low voltage signal in the hydrogen unit of the system. He will continue to perform maintenance on it for the rest of the week. So how does the US oxygen generation system work? It uses electrolysis to convert water into oxygen and hydrogen using electricity. Electricity is directed through electrodes in contact with liquid water from the station's recycled water supply. Bubbles of oxygen are generated and released into the station's air. Hydrogen is also produced and this is used in the saboteur reaction to convert carbon dioxide into methane and water. Fortunately, the astronauts aren't going to run out of oxygen. The Russian electron system also uses hydrolysis to split water into oxygen but it hasn't been very reliable over the years. If the electron system breaks, astronauts can also use the Vika system or solid fuel oxygen generation. The Vika system uses canisters containing lithium perchlorate which are burnt to create oxygen. The system was originally developed for MIR and was the cause of the fire on MIR in 1997 but the whole system was upgraded before it was used on the ISS. And of course, astronauts can always breathe air from the oxygen tanks stored on board. But what about in the future? What will astronauts breathe on Mars and beyond? The Vika system needs canisters that need to be resupplied and both the electron and OGS systems need water. Moxie is a payload on NASA's Mars 2020 rover which will use solid oxide electrolysis to make oxygen from carbon dioxide which makes up about 96% of the Martian atmosphere. It's a 1% scale model of an oxygen generator that NASA plans to send to Mars sometime in the future, if Moxie works. This isn't the only way to turn carbon dioxide into oxygen. Nature had that figured out millions of years ago. Photosynthesis converts carbon dioxide to oxygen using sunlight. Both plants and algae have been proposed to manage the atmosphere for humans on Mars. Both plants and algae can be edible and can tolerate super high levels of carbon dioxide. In fact, photosynthesis becomes even more efficient at higher levels of carbon dioxide. How neat is that? In the meantime, I wish the ISS crew a speedy fix of the OGS in preparation for three more crew members arriving next week. If you thought this video was pretty neat, be sure to like, subscribe and share it with your family and friends. And I'd like to know, what oxygen generation system do you think we should use as humanity explores space? Let us know in the comments below or via social media. Personally, I'd like to see humans use plants for both oxygen and food on Mars. And of course, these videos are not possible without the generous support of our crowd funding supporters, our Patreon patrons. So thank you so much for all of your support. Thank you to our founders, architects, engineers, ambassadors and dreamers of tomorrow. And if you'd like to help support these space pods, head on over to patreon.com slash space pod. The more we get, the more space pods we can make. So every dollar helps. Thank you. My name is Lisa Stodzianowski and until next time, keep on discovering.