What is 1G


How much g can a person withstand?


This question is synonymous with the question of the maximum acceleration or the maximum force that can act on a human organism without damaging it. Acceleration describes the change in speed over time. Since Newton we have known that there is a direct connection between the force that acts on a body and the acceleration it experiences as a result - force is equal to the mass of the body times the acceleration. One form of acceleration that determines our life on earth is gravitational acceleration, which is called "G" referred to as. It determines the gravitational force acting on us. In the vicinity of the earth's surface it is almost constant (G = 9.81m / s2).

The acceleration of gravity - 1g - is used as a measure of other accelerations. During the acceleration of a car, the occupants are exposed to an acceleration of approx. 0.3 G, the driver of a Formula 1 racing car experiences 1-1.5 at the start G and in cornering up to 5 G. The flight maneuvers of a passenger aircraft are designed so that the load on the passengers 1.5 G does not exceed. Astronauts experience accelerations of 3-4 on takeoff G, and in their orbit around the earth they are weightless (0 G). When re-entering the earth's atmosphere, the astronauts in the US space shuttle are exposed to a load of around 1.5 G and in the Russian Soyuz capsules of up to 10 G exposed. In roller coasters, up to 6 G can be achieved.

When asked which G-A person can withstand stress, the amount of acceleration and the time and especially the direction in which this stress acts also play a major role. If a person is in a sitting position and is accelerated upwards, a feeling of greater body weight arises, and from approx. 3 G it becomes almost impossible for him to get up. In particular, affect high G- Stresses our bloodstream. With positive acceleration upwards, the blood sinks into the legs. This results in 2-4 after a few seconds G Visual disturbances, and at 5-6 G sets in unconsciousness as a result of restricted cerebral blood flow. As soon as the positive acceleration forces are no longer effective, the blood circulation in the brain and eyes is normal again and an awakening from unconsciousness occurs.

Negative downward accelerations, during which blood flow towards the head, can be tolerated considerably more poorly by humans. Loads up to -1 Gthat act on a person who is upside down, for example, are usually endured by healthy people without any problems. However, even small excesses of this mark are perceived as very uncomfortable and under certain circumstances even painful due to a feeling of pressure in the head and eyes. Already at about -3 G the so-called “redout” effect can occur. This is a visual impairment caused by blood being forced into the head and thus into the retina and blood vessels of the eye. This causes the field of view to be colored red. From 5 G it can also lead to unconsciousness. Furthermore, after a few seconds with this load there is a risk that vessels will burst and cerebral hemorrhage will begin.

Accelerations that act perpendicular to the body axis are much easier for the human organism to cope with. Until about 6 G an increased pressure on the supporting body parts is perceived. Until 12 G it becomes difficult to breathe and the level of oxygen in the blood drops. This can be countered with an increased oxygen content in the breathing air, so that exposure of 15-20 G seem possible without harm to the body. In addition to stressing the blood circulation and breathing, high accelerations also mean great forces on the human skeleton and muscles, which can lead to injuries. Pilots and astronauts are tall G-Loads sometimes exposed for long periods of time. You will be prepared for your missions through special physical training, primarily to strengthen the neck, leg and back muscles. In addition, pilots and astronauts wear pressure suits for this purpose. To the very high G- To be able to withstand the stresses of re-entry into capsules, the astronauts are in a lying position against the direction of flight.