The Ultimate Roller Coaster
I had the opportunity to ride in NASA’s KC-135, which is a specially equipped plane used for testing the effect of weightlessness. The effect that it had on my body can be summed up in the nickname given to the plane, which is “THE VOMIT COMET.”
Many find a roller coaster ride thrilling. But riders in NASA’s KC-135 airplane experience the “ultimate roller coaster ride.” This plane, aptly called the “Vomit Comet”, allows passengers to experience changes in gravity from 0G to 2G. Without restraints and being confined within the plane’s padded inside surfaces, things and people float at 0 G. But there are dangers that most are not aware of.
Before boarding the plane we were given specific directions for how to vomit. At the time I wondered about the need for this extended training. Who doesn’t know how to vomit? On Earth, when you vomit the material leaves your mouth and falls downward. This is because of gravity, which is 1G on Earth. Vomiting at 0G is a different story. Your body may propel fluid from your stomach out of your mouth, but with no gravity, the material floats instead of falling. To keep vomit contained, a barf bag must be held tightly around your mouth. When the bag is removed, you are to use it to rub any liquid on your mouth into the bag.
During the ride, periods of zero gravity lasts only about 30 seconds then the G force increases rapidly to 2Gs. Everything that is floating is slammed down twice as hard as it would be from the same height at Earth’s normal gravitational force of 1G. To prevent injuries, one of the NASA crew gives a loud warning of “Coming Down.” Hearing this you know that you have only seconds to get to the floor and secure your self.
The changes in the apparent gravity within the plane are due to shape of the flight path, which is much like that of a roller coaster’s track. After leveling off at 26,000 feet (7,925 meters) the pilots pulled the plane upward at a 45-degree angle. About 60 seconds later, the plane started “over the top” falling 8,000 feet (2,440 meters) or so until the plane pointed down about 30 degrees. During this fall lasting about 30 seconds the plane’s acceleration equaled that of Earth’s acceleration of gravity. Thus, resulting in a zero G force inside the plane. But all too quickly the G force increases. The change from 2G to 0G to 2G and so on was repeat as the plane “parabolas,” a term used to describe the up and down curved shape of the plane’s path. Some record that since the pilots are strapped in and completely focused on flying smoothly, they don’t notice the constant shift in G-forces. But I beg to disagree. Due to a mishap caused by hanging camera’s around my neck (discussed later), I spent time being strapped in a seat. I was extremely focused on my project and I noticed every micro-change in the gravity. Unlike the pilots, my project was keeping a barf bag tightly secured to my mouth. At the time I was proof that the plane had been properly tagged “Vomit Comet.” The few who became ill on the flight including me were able to walk off the plane. I was also successful in performing some of the experiments I had planned as well as take pictures. This was all done with a plastic barf bag over my mouth.
Initially I became ill because I lost my focus. This was due to cameras hanging by cords around my neck. We were told to focus on a spot on the wall during the first two parabolas. The idea was for our bodies to adjust to the changes in gravity before we turned lose and floated around. I never got to float around but did experience walking through the plane at 2G. My legs felt so heavy. It was like being in a dream. But during the first two parabolas I touched the hanging cameras and they started rotating resulting in the camera cords twisting around my neck. I can say with certainty, without gravity a moving object will continue in motion. During reduced gravity the camera’s starting floating. This would have been ok had I not touched them resulting in their starting to spin which tightened the cord around my neck. You bet I lost focus at this point. I was much more concerned with breathing. I didn’t want to float off so I held on with one hand and tried to pull the cord away from my throat with my other hand. It seemed like eternity but when I later viewed a video of the flight, several flight crewmen came quickly to my rescue. They removed the cameras and had me seated in the back of the plane in a very short time. While you may not have the opportunity to ride in the “Vomit Comet” it is exciting to learn about the results of experiments in microgravity.