Being in space is characterized by weightlessness, unlike piloting a fighter jet in which G-force rises. Activity in an environment in which the G-force is negligible holds many challenges and just as many experiences. In honor of the anniversary of the Physicist Issac Newton’s death, we went out to check what happens when gravity changes

Shachar Zorani | Translation: Ofri Aharon

Legend has it that there was once a man named Isaac. One day, Issac decided to rest under a tree, when suddenly an apple fell on his head. The apple that later led to one of the most important scientific discoveries in history – gravity. Since its discovery and until this day, the research of gravity has advanced and branched out greatly and many derivatives have been added to the phenomenon. One of them being G-force, originating from gravity, but is not directly connected to gravity on earth, rather to gravitational acceleration.

Gravitational forces influence every daily movement we make: starting from sitting on chair, going up an elevator and to braking a car. The laws of physics don’t skip over aircrews as they experience much greater G-forces in the cockpit than people do on land. In the air, G-force rises and everything feels much heavier. One of the pilots described the influence G-force has in air as, “as if a tank is running over you”, a feeling experienced by many aircrew members. The equation is simple: as the radius of the aircrafts turn lessens, the G-force is greater.


From the Cockpit to Space: Life with Negligible G-Force

Now, the relationship between the G-force and maneuvering is clear and what the pilot in the cockpit feels is also clear. So what happens when the G-Force is negligible, meaning, having no feeling of gravity? Lt. Col. (Res.) Issac Mayo, IAF pilot who was training for flight in space in NASA, wrote in his book “Over the Horizon”, on flight without gravity.

In space the G-forces are negligible, which make it seem like the perfect playground: astronauts float around the space station, with their hair scattered all over the place and their arms and legs hanging limply. Weightlessness is one of the most prominent and familiar characteristics of space travel. On the one hand it is very enjoyable, but also presents a big challenge for anyone who wants to live under its influence for a long period of time. “There isn’t a big difference between studying the space shuttles system than studying about a new IAF aircraft. The hard part simulating zero-G by using a special aircraft that maneuvers in the air. It would reach zero-G for 25 seconds. The first 20 times it was nice, but after that I said ‘ok, I get the point’ and I had to sit in a chair to relax”.

The journey to space is a difficult challenge. Even with advanced technology and acquired experiences, we can’t change the laws of nature. Within the first seconds of the journey to space, the astronauts deal with the high acceleration of the take-off, physically manifested in extremely powerful G-forces activated on their bodies and then, when they reach the space station and enter orbit, they experience a feeling of weightlessness. Because of the many changes and negligible gravity, the astronaut’s bodily functions become complicated and even with the prolonged and intense training they endure, many astronauts are affected by the symptoms space travel and are likely to suffer from anatomical and physiological changes, such as weakening of the bones. In order to overcome these symptoms they sometimes take medicine to avoid nausea and vomiting and wear their spacesuits, that are used as an outer shroud that protects them from the extreme conditions in space and contain all the necessary accessories, such as a system that adjusts the pressure in air and provides oxygen.

Negligible G-force may constitute of a physical and emotional barrier for the astronauts at first, but may, at times – be an enjoyable experience. Lt. Col. (Res.) Mayo shared with the IAF Magazine in an interview: “the most interesting stages of our training were of course the practical stages. We all awaited the day we would simulate space travel. When it arrived, we were put into teams and went into the special aircraft in which we conducted the simulation zero-G simulation. The flight reminded me of flying in a fighter jet, when you feel like you are in zero-G and the same feeling of pleasant levitation is created”.


From the Cockpit to Space: Life with Negligible G-Force

Lt. Col. (Res.) Issac Mayo | Photo by: NASA