In late June, I traveled to Southampton, PA, for a one-day Orbital Space Flight Training certification at the NASTAR Center with Glenn King. The training day ran from about 9 AM to 3 PM. When I first arrived, I felt a mix of excitement and anxiety. I had experienced around 2G’s during a Zero G flight before, but I had never gone beyond that, and I was nervous about how my body would handle it. However, as soon as I started learning, my nerves began to settle.
The first half of the day was dedicated to understanding acceleration and motion physiology. We delved into sustained accelerations, known as G-forces, and learned special techniques to handle their side effects, like the feeling of not being able to breathe. We also got an overview of the training flights we would be doing and learned about the centrifuge.
What is a centrifuge/centrifugal force?
A centrifuge is a rapidly rotating device that applies centrifugal force to whatever is inside. A high-performance human centrifuge uses centrifugal force to simulate G-forces on the person inside. This is often used to train fighter pilots to handle the G-forces they would experience in actual flight. Centrifugal force refers to an outward force generated by external acceleration and is based on Newton’s third law of motion: for every action, there is an equal and opposite reaction. For example, when experiencing inertial force traveling upwards in a rocket, it causes centrifugal force to be exerted on the rocket, and consequently, on the people or objects inside.
There are three types of G-forces: Gx, the most common, which people sometimes experience in small amounts when accelerating quickly in a car, and is front-to-back; Gz, which is up-and-down or head-to-foot; and Gy, which is right-to-left or side-to-side.
A G-force is a dimensionless ratio that describes an applied acceleration relative to the acceleration of gravity. They are measured by the acceleration of an object in m/sec² divided by 9.8 m/sec². So, one G is experiencing Earth’s normal gravity.
The device I used is called the STS-400, which has a 25-foot arm and simulates up to 20 Gz’s maximum.
When experiencing higher levels of G-forces, you can feel intense chest pressure. Many people describe it as feeling like an elephant is sitting on your chest, but I think a more accurate description is like having the front of your body wrapped tightly in plastic wrap and being pulled back in a chair at a sustained G-force, which can make it it difficult to breathe.
To combat this, they teach you a pressurized breathing technique. It involves taking a deep inhale and then exhaling as if you are breathing through a straw. This technique helps increase lung pressure and forces oxygen into the bloodstream, making it easier to breathe under high G-forces.
Lets’s Fly!
My first flight was a Gx Conditioning flight, which involved a gradual increase to a sustained +3.0 Gx and then progressing to a sustained +6.0 Gx. If you weigh 100 pounds, that translates to having 600 pounds of pressure on you! They start with higher G-forces as a conditioning treatment. Since this was my first time in a centrifuge, I felt a bit claustrophobic knowing I was in a rapidly spinning metal chamber. However, after a few minutes, I realized that panicking would only make things worse. The +3.0 Gx was manageable, but when I reached about +4.5-5.0 Gx, I began to feel my chest tighten and my throat close. I used the pressurized breathing technique they taught me, which was very helpful.
I was initially concerned about feeling nauseous during the sustained acceleration, but the only negative side effect was a bit of vertigo during the deceleration.
The second flight was a launch and ascent profile lasting 10 minutes, simulating the launch and ascent of the Falcon 9 rocket, peaking at 4.4 Gx.
The third flight was a 10-minute re-entry and splashdown profile, simulating re-entry through Earth’s atmosphere, parachute deployment, and splashdown, also peaking at 4.4 Gx. The simulation includes awareness calls so nothing takes you by surprise.
My fourth flight was a 7.5-minute Launch Escape profile, simulating a Dragon launch escape from the Falcon 9 rocket, culminating in a splashdown and peaking at 3.4 Gx.
I enjoyed the experience so much that I opted for a fifth flight, which simulated Virgin Galactic’s launch and re-entry profile. This flight optimizes both Gx and Gz.
Thoughts and comments
I was really anxious at first, but it ended up being one of the most fun experiences I’ve had in a while—I didn’t want to leave! I kept opting to redo flights or try new ones because the adrenaline and excitement were unlike anything else. When I finished, I turned to my dad and said, “I understand why people want to be fighter pilots.”
I’m so glad I got to experience this because it means that on my actual launch day, I won’t have to deal with any anxiety about G-forces since I’ve already been through it. I can just sit in the rocket and enjoy the ride. After my time at NASTAR, my body felt heavier than usual, and I was mentally and physically exhausted, but I was assured that this was normal.
Overall, it was an incredibly enriching experience and made me even more excited for my actual space launch.