People often see astronauts floating in space and assume they are simply having a leisurely time in the zero gravity environment. While that is true, there is more science to it than many people realize. The reason astronauts float in space is that the micro-gravity environment has no pressure from Earth’s atmosphere. It’s similar to being on top of a mountain – you would also float because of the lack of air pressure. For an astronaut to have any kind of normal life aboard a spacecraft, engineers must take into account their weightless existence and build components that would either reduce their weight or neutralize its effects. This reduces stress on the astronaut and the spacecraft, minimizing safety risks. This article will explore why do astronauts float in space shuttle and answer other related questions you may have about this fascinating topic.
What is Zero Gravity?
Zero gravity is the weightless condition in which there is a negligible effect of the Earth’s gravity on a body. In this state, there is no net force on objects that are not in motion. As an example, an object in free fall in a vacuum will experience zero gravity.
More generally, zero gravity also refers to the absence of a gravitational field, which can be caused either by the absence of a field or the absence of a nearby source that produces it. Zero gravity does not mean any gravity, since gravity exists everywhere.
It does, however, mean that the effects of gravity are negligible. The condition that produces zero gravity is usually a high altitude above the ground, where the air is too thin to produce a significant amount of gravity.
Floating in Space
There is no surface in space to stand on, so astronauts float in the weightless environment of space. The best way to understand this is to visualize two people in swimming pools – one in a shallow pool and the other in a deep one. Both are floating but in very different ways.
The person floating in the deep pool might keep herself afloat by using a swimming motion with her arms and legs. The person floating in the shallow pool might simply lay back and relax, using the force of the water to push against her body.
In a spacecraft, astronauts use a combination of these two techniques to stay on the move. They propel themselves in a swimming motion with their arms and legs, but they also use force to push against their bodies. That force is the difference in air pressure inside the spacecraft and outside the spacecraft.
Orbits and Weightlessness
When the Space Shuttle is in orbit, astronauts are experiencing a state of weightlessness. There is virtually no gravity outside the Earth’s atmosphere, so they are floating. And while they are in orbit, the Shuttle experiences weightlessness.
The difference between the two is that the Shuttle has a constant speed and direction, while an orbiting object like the International Space Station has a constant speed but changes direction.
When an orbiting object passes over the North and South Poles of the Earth, it is moving at a speed that is tangential to the surface of the Earth. At those two points, the object’s speed is the same as the Earth’s rotational speed.
Airlocks and Equalization
When a spacecraft docks with another spacecraft, astronauts move from the low-pressure environment inside the Shuttle to the higher-pressure environment of the other craft. The pressure difference will cause a difference in the amount of air inside their bodies.
To prevent damage to their bodies, astronauts use an airlock to equalize the pressure inside their bodies with the pressure outside the spacecraft. Astronauts pressurize their bodies by exhaling air through their mouths and noses.
In space, astronauts rely on an airlock to move from one section of a spacecraft to another. They also use an airlock to exit a spacecraft when they are ready to return to Earth. Airlocks are pressurized chambers with an interior door that opens to another part of the spacecraft.
They are commonly used on the International Space Station (ISS) and on spacecraft to allow astronauts to move between different sections without wearing space suits.
Zero-Gravity Stations
Zero-gravity stations are facilities that achieve weightlessness by creating a state of free fall. The Russian Space Station Mir, the Japanese Space Station (formerly known as the Japanese Experimental Space Station, or JAXA Space Station), and International Space Station (ISS) are all examples of these facilities.
There are advantages to a facility that can achieve free fall versus one that is constantly in orbits, such as lower costs of construction and maintenance and better accessibility to the public.
The Bottom Line
People often see astronauts floating in space and assume they are simply having a leisurely time in the zero gravity environment. While that is true, there is more science to it than many people realize. The reason astronauts float in space is that the microgravity environment has no pressure from Earth’s atmosphere.
It is similar to being on top of a mountain – you would also float because of the lack of air pressure. For an astronaut to have any kind of normal life aboard a spacecraft, engineers must take into account their weightless existence and build components that would either reduce their weight or neutralize its effects. This reduces stress on the astronaut and the spacecraft, minimizing safety risks.
