An important part of preparing for suborbital space missions is to understand cabin depressurization and how to identify slow-onset hypoxia.
As part of the Advanced PoSSUM Academy course, we were enrolled in the Southern AeroMedical Institute’s Hypoxia Training for Non-Pilots course. This was to provide us with a unique opportunity to gain experiential knowledge of our hypoxia symptoms.
Three people at a time, we went into the hypobaric chamber and took our seats. Each station had a flight simulator, oxygen mask, pulse oximeter sensor, and a communications headset. Our task was simple: Don’t crash and fly the simulator as instructed. The typical hypoxia trainee would come from an aviation background and would already know how to fly a plane. The funny part about our particular groups was the PoSSUM participants came from many different backgrounds (e.g. doctors, scientists, educators) and many of us didn’t understand how to read the controls on the simulator. This made for a hilarious conversation with the flight controller when they gave new coordinates to fly toward and the pilot had no clue where to even look.
My Hypoxia Symptoms
As the cabin pressure began to drop, I could see my oxygen levels going down on the pulse oximeter. At first, I didn’t notice any symptoms. As the chamber rose to a higher simulated altitude, I noticed my first symptom: Warm face. As the sim continued, I realized it was getting a little harder to concentrate on flying the flight simulator when I felt my second symptom: Tingling fingers. At this point I had no concept of time between symptoms or where I was in the instructed flight pattern. In that moment, my third symptom occurred: Cold feet. After the third symptom, the flight controller asked my oxygen levels and the sensor was reading 71%. They said, “You have experienced cabin depressurization, don your oxygen mask.” When donning the mask, I put it on over my headset. The support staff in the chamber came over and helped me remove the headset and put on the mask properly. What I didn’t realize until I saw the video, was how slow I was moving. Within one minute of getting oxygen again, my pulse oximeter was reading 99% again.
It’s was pretty amazing to see and feel how fragile and adaptive my body was in this scenario. This training was extremely useful as it provided me with experiential knowledge of the symptoms and what could occur should a slow-onset cabin depressurization would happen onboard a sub-orbital spacecraft. What was also useful was to see everyone else’s symptoms and have a better understanding of how to recognize symptoms in other crew members should they exhibit them first. Going into this training I had no clue what to expect as I had never participated in a low oxygen type activity. Having completed it, I feel more prepared to identify symptoms as they happen to me and to others around me.
Featured image is when I was in the hypobaric chamber during slow-onset hypoxia training. Photo Credit: Yvette Gonzales