What, Exactly, Is Dunker Training?
The infamous dunker is many would-be astronauts' first introduction to commercial spaceflight training. And, as Brien explains, it's a doozy.
One of the more intimidating training exercises I've had to endure as a part of my commercial spaceflight training was dunker training. For those who aren't familiar, it involves being strapped into an aircraft seat within a purpose-built fuselage, then being submerged in water, often upside-down. You can see what the dunker looks like in Figure 1.
Dunker training is not unique to the space program. The military uses dunker training to teach service members how to survive a helicopter crash in the water. The private sector also uses the dunker for crash survival training. For example, crews that travel to offshore oil rigs by helicopter often go through dunker training to help prepare them in case their helicopter went down in the ocean.
I've never heard an official explanation of why going through the dunker training is required in the commercial space program, but it is one of the first training exercises you have to go through as a commercial astronaut candidate. In fact, I initially started my commercial spaceflight training in a different program than the one that I am in now, and both programs required dunker training. In other words, I have been through the course multiple times.
In some ways, the idea of having to go through dunker training in preparation for a space mission seems kind of odd. After all, we don't really do much with helicopters, and aside from the infamous Grissom incident, having a capsule sink in the ocean really isn't a thing.
My guess as to why commercial astronaut candidates are put through Dunker training is because the training pushes most people well outside of their comfort zones. It forces participants to face their fears, endure a significant amount of discomfort, and walk away from it all with the sense of accomplishment that can only come from persevering through something really difficult. This means that even though the dunker has very little to do with going to space, it's actually the perfect introduction to spaceflight training.
I have to confess that prior to my first time going through dunker training, I was really intimidated. For various reasons, the training was scheduled in a way that resulted in me being the only one in my class training to go to space. Everyone else was from the military. I had watched quite a few YouTube videos of military members going through dunker training, and it looked really tough.
One thing that immediately struck me as I watched those videos was that the military personnel going through the training all appeared to be about 20 years old. At the time, I had just turned 42. Even though I had been spending a lot of time in the gym and was probably in the best physical shape of my life, I kept wondering if I had a sufficient level of fitness to be able to keep up with people half my age.
I also wondered how long I would be able to hold my breath. In the weeks leading up to the training, there were several times when I would sit at the bottom of a swimming pool while my wife kept track of how long I could remain submerged. Interestingly, I wasn't the only one who had concerns about how long they could hold their breath. The second time I went through dunker training, I was with other commercial astronaut candidates rather than being with the military. The night before the training was to start, a friend who was about to go through the training for the first time nervously asked me if the required breath holds were in the duration of seconds or minutes.
For those wondering, the amount of time that you spend underwater varies based on what it is that you are asked to do. I haven't actually timed the runs in the dunker. Most probably only require you to hold your breath for 30 or 40 seconds, but it feels a lot longer than that when you are in the moment. I was really surprised when I saw some of the videos from the training and realized just how short of a time I was actually underwater.
What Is Dunker Training Really Like?
Dunker training involves going for numerous rides in the dunker over a period of a few days. Each of these rides is different, but the basics tend to be consistent from one run to the next. You are strapped into your seat, plunged underwater and flipped upside-down. This means that sinuses are completely flooded with water. Once the dunker stops moving, you have to get the door open, get yourself unstrapped, then swim through the door and to the surface.
Even though almost all of the runs in the dunker share these common elements, there are quite a few different ways in which the instructors switch things up on you. Sometimes you are blindfolded, although technically the blindfold doesn't make much of a difference since they usually turn the lights out or tell you to close your eyes. The training facility is also set up to simulate various environmental conditions. For example, they can create a torrential downpour, thunder, simulated lightning, wind and more.
None of this makes all that much difference while you are in the dunker, except for possibly increasing your level of anxiety. It does, however, make things more difficult when you reach the surface since you still have to swim to the other end of the pool. You can see an example of the environmental effects in Figure 2. It isn't a great picture, but the spray that you see above the dunker is from the rain machine.
As you progress through the various dunker exercises, the instructors introduce additional challenges that substantially increase the difficulty. For example, they might tell you that you are not allowed to exit the aircraft through the door closest to you. Instead, you might have to make your way across several seats, across the aircraft's center aisle, and find a door on the opposite side of the aircraft. If this seems trivial, remember that you are doing it upside-down, in the dark, underwater.
One of the challenges they introduce on the second day of training is that of using emergency air. Once you are upside-down and the dunker stops moving, you are supposed to remove an air bottle from where it is stored, turn on the air, put a regulator in your mouth and breathe off of the regulator. A lot of people hate this part of the class because you have to focus on breathing only through your mouth so you don't accidentally inhale any water through your nose. Even so, I found this to be the easiest part of the training. I have been scuba diving for nearly 30 years and hold multiple advanced dive certifications. Breathing off a regulator underwater has become second nature to me, so I found that part of the dunker training to be effortless.
That, of course, isn't to say that the course as a whole was easy. It wasn't. Even so, it proved to be a highly satisfying, adrenaline-fueled introduction to commercial spaceflight training. If you want to see more of what it was like going through dunker training, you can find one of the videos here.
Brien Posey is a 19-time Microsoft MVP with decades of IT experience. As a freelance writer, Posey has written thousands of articles and contributed to several dozen books on a wide variety of IT topics. Prior to going freelance, Posey was a CIO for a national chain of hospitals and health care facilities. He has also served as a network administrator for some of the country's largest insurance companies and for the Department of Defense at Fort Knox. In addition to his continued work in IT, Posey has spent the last several years actively training as a commercial scientist-astronaut candidate in preparation to fly on a mission to study polar mesospheric clouds from space. You can follow his spaceflight training on his Web site.