A commonly understood fact is that breathing is difficult at high elevations because of the thin air. However, the meanings behind “hard to breathe” and “thin air” are often hidden or under-appreciated. Informed by a hot balloon incident from the 1800s, we will ask why oxygen is so important for the human body and appreciate how our hearts, lungs, and blood is essential for sustaining life. Then we will look at what happens when these processes break down including medical signs and symptoms to answer what happened hundreds of years ago. Finally, we will look at countermeasures and ways that humans overcome the threat of hypoxia in aerospace and space travel.

Scuba divers know that the end of the dive can be the most dangerous because bubbles can form causing terrible damage. Decompression Sickness was first understood in French coal miners but plays a crucial role in aerospace applications. The space environment involves moving between pressure gradients which brings these risks front and center. The other concern with different pressure gradients is hyperoxia where too much oxygen can also cause trouble. The artificial atmospheres onboard the International Space Station and in space suits must be tightly controlled to avoid these issues.

Aircraft causalities almost always end with a crash. Crashes are a form of acceleration where a moving plane comes to a rapid stop causing massive trauma for the pilot and passenger. Acceleration from high speed turns, maneuvers, and lift-off can contribute to pilots passing out and losing control of their craft. We fight against these G-Forces with blood pressure in the hopes of avoiding these Losses of Consciousness and Trauma.

Once we leave Earth, we lose so many of the protections that keep us safe. With the strong presence of Earth's gravity, our eyesight begins to fade, our bones start to crumble, and our muscles will atrophy. The atmosphere and magnetosphere shield us from solar radiation and we leave behind most of our social connections on board a spaceship. To survive a journey to Mars, Space Doctors will need to be in constant communication with astronauts and plan the mission knowing these risks. The journey may be perilous but we can engineer solutions to persevere and overcome.

Should astronauts prevent all of the issues needed for a trip to the Red Planet, there will be new health concerns to live on Mars. This week is especially theoretical as we look into engineering and medical designs to survive in an incredibly limited environment. Scarce resources also pose ethical concerns as some equipment may need to be left behind at the start of a mission and a Martian parasite could risk the extinction of the human race. However, like every issue throughout this course, once we've identified an issue, we can overcome it! We leave you, asking, "Do you have what it takes to be an astronaut?"