The force of gravity does not affect the ISS. Why astronauts can not cry in space

The science

In fact, the astronauts, of course, also cry. However, as explained by NASA, in microgravity, tears do not flow down, as on Earth, but remain in place. They gather around the eyeball.

Moreover, such tears bring a lot of discomfort.

In May 2011, the astronaut Andrew Fustelmay have been the first to know what is happening when eyes in space are watering.

During the spacewalk, Fustel felt a strong burning sensation in the eye. As it turned out later, a bit of anti-fogging agent got into the cosmonaut's helmet, which caused tearing. He managed to rub his eyes on a spongy device, which is usually used to pinch the nose to equalize pressure, and to alleviate his condition.

According to the scientific explanation, tears should not cause pain. Although we do not know exactly why we cry, tears have a softening effect. But, as you know, weightlessness adversely affects the human vision, which is caused by the displacement of fluid to the head. It is also possible that dry eyes appear in space, and a sudden ingress of liquid may cause a burning sensation.

As another cosmonaut Ron Parise explained, if a lot of tears are going, they come out of the eyes and float around. In other words, you can watch with pleasure as your weightless tears float before you.

State of weightlessness

What is the state of weightlessness? We are accustomed to believe that astronauts are floating in space, acting contrary to the laws of gravity. Because many believe that there is no gravity in space. In fact, gravity exists everywhere in the Universe and is the most important force affecting everything that exists in space.

What happens to an astronaut who is in zero gravity? More precisely, this condition could be called free fall.

Why do not astronauts fall to Earth? There is a law of acceleration of free fall. If an astronaut drops an apple on a space station, then all of them will fall: an apple, an astronaut, and a station. Only they do not fall to the earth, but around it, as they accelerate relative to the Earth. Objects in Earth orbit seem to be floating, although in reality they are moving at the same orbital speed as the spacecraft, more than 28,000 km per hour.

Zero gravity liquid

Experiments with water in zero gravity on the International Space Station.

Drinking water in space is also not an easy task. Since water does not leak under microgravity conditions, all the liquid from the containers is drunk through a straw. Without it, the astronauts would have to “bite off” small pieces of a bubble of floating water.

How do astronauts go to the toilet? Water, for obvious reasons, also can not be used for draining. Waste products are sucked into a special funnel with a hose, and then thrown into space.

This video allows us to get acquainted with some rather interesting ideas about the conditions of weightlessness onboard the ISS and shows why astronauts actually seem to be floating in weightlessness.

When asked why objects and astronauts in the conditions of the space orbital station are in a state of weightlessness, many people give the following answer:

1. There is no gravity in space, so they do not weigh anything.
  2. Cosmos is a vacuum, and there is no gravity in a vacuum.
  3. The astronauts are too far from the surface of the Earth, so that the force of its attraction can act on them.

All these answers are wrong!

The main thing to understand is that there is gravity in space. This is a fairly common misconception. What keeps the moon in its orbit around the earth? The force of gravity. What keeps the Earth in orbit around the sun? The force of gravity. What prevents galaxies from flying apart? The force of gravity.

Gravity is in all space!

If you built a tower on Earth with a height of 370 km (230 miles), which is equal to the height of the ISS orbit, then the force of gravity acting on you at the top of the tower would be almost the same as on the surface of the earth. If you decided to take a step from the tower, you would rush to Earth in the same way as Felix Baumgartner did when he jumped from the edge of space. At the same time, we do not take into account the low temperatures that will instantly freeze you, or the lack of air or aerodynamic drag will kill you, and falling through layers of atmospheric air will cause all parts of your body to experience what it means to “tear off three skins”. And a hard landing on Earth will also cause you a lot of inconvenience.

So why don't a space orbital station or satellites in orbit fall to Earth, and why do astronauts and objects inside the international space station (ISS) or any other spacecraft seem to be weightless?

It's all about speed!

Cosmonauts international space station   and other objects in Earth orbit do not float - in fact, they fall. But they do not fall to Earth because of their enormous orbital speed. Instead, they "fall around" the earth. Objects in Earth’s orbit should move at a speed of at least 28,160 km / h (17,500 miles per hour). Therefore, as soon as they are accelerated relative to the Earth, the force of gravity of the Earth immediately bends and leads the trajectory of their movement downward, and they will never overcome this minimum of approach to the Earth. Since the astronauts have the same acceleration as the space station, they experience a state of weightlessness.

It happens that we too can experience this state on Earth, at the time of the fall. Have you ever been to the ride “roller coaster”, when immediately after passing the highest point, when the cart starts to roll down, your body lifts up from the seat? If you were in the elevator at the height of a multi-storey skyscraper, and there was a cable break, then while the elevator fell, you would float in zero gravity in the elevator car. Of course, in this case, the final would be dramatic.

And then, you probably heard about an airplane that provides a state of weightlessness (“Vomit Comet”) - an KC 135 airplane that NASA uses to create short-term states of weightlessness, train cosmonauts and test experiments or equipment in zero gravity (zero-G) as well as for commercial flights in zero gravity, when the plane flies along a parabolic trajectory, as in a roller coaster ride (but at high speeds and at high altitudes), passes through the top of the parabola and rushes down, then in m cop crash are weightless conditions. Fortunately, the plane goes out of a dive and leveled.

However, let's go back to our tower. If instead of an ordinary step from a tower you had made a jump from a run, your forward energy would take you far from the tower, but at the same time, gravity would have blown you down. Instead of landing at the base of the tower, you would land at a distance from it. If during a run you increased your speed, you could jump further from the tower before you reached the ground. Well, if you could run as fast as a reusable spacecraft and the ISS orbit around the Earth at a speed of 28.160 km / h (17,500 miles per hour), then your arc trajectory would make a circle around the Earth. You would be in orbit and experience a state of weightlessness. But you would fall without reaching the surface of the earth. True, the suit and supplies air suitable for breathing, you would still need. And if you could run at a speed of about 40.555 km / h (25,200 miles per hour), you would jump out of the earth immediately and start spinning around the sun.

According to the law of the world, all bodies are attracted to each other, and the force of attraction is directly proportional to the masses of the bodies and inversely proportional to the square of the distance between them. That is, the expression "lack of gravity" does not make sense at all. At an altitude of several hundred kilometers above the Earth’s surface, where manned spacecraft and space stations fly, the Earth’s gravitational force is very large and practically does not differ from the gravitational force near the surface.

If there was a technical possibility to drop an object from a tower 300 kilometers high, it would begin to fall vertically and with the acceleration of free fall, just as it would fall from a height of a skyscraper or from a height of human growth. Thus, during orbital flights, the force of gravity is not absent and does not weaken on a significant scale, but is compensated. In the same way as for watercraft and aerostats, the gravitational force of the earth is compensated by Archimedean force, and for winged aircraft, by the lifting force of the wing.

Yes, but the plane flies and does not fall, and the passenger inside the cabin does not fly like astronauts on the ISS. During normal flight, the passenger perfectly feels his weight, and from the fall to the ground he is not directly supported by the lifting force, but by the reaction force of the support. Only during an emergency or artificially caused sharp decline does a person suddenly feel that he is no longer pressing on the support. There is weightlessness. Why? And because if the loss of height occurs with acceleration close to the acceleration of free fall, then the support no longer prevents the passenger from falling - she herself falls.

spaceref.com
  It is clear that when the plane stops a sharp decline, or, unfortunately, falls to the ground, then it becomes clear that gravity has not disappeared anywhere. For in terrestrial and near-earth conditions, the effect of weightlessness is possible only during a fall. The actual long fall is orbital flight. A spacecraft moving in orbit with the first cosmic velocity prevents inertia from falling to Earth. The interaction of gravity and inertia is called "centrifugal force", although in reality such a force does not exist, it is somewhat fiction. The device tends to move in a straight line (tangential to near-Earth orbit), but the earth's gravity constantly "twists" the trajectory of motion. Here the equivalent of the acceleration of free fall is the so-called centripetal acceleration, as a result of which it is not the value of the velocity that changes, but its vector. And so the speed of the ship remains unchanged, and the direction of movement is constantly changing. Since both the ship and the astronaut are moving at the same speed and with the same centripetal acceleration, the spacecraft cannot act as a support on which the weight of a person is pressing. Weight is the force of influence of a body on a support that prevents fall from arising in the field of gravity. And the ship, like a sharply falling plane, does not prevent falling.

That is why it is completely wrong to talk about the absence of terrestrial gravity or the presence of “microgravity” (as is customary in English-speaking sources) in orbit. On the contrary, the attraction of the earth is one of the main factors arising on board the phenomenon of weightlessness.

One can speak about true microgravity only when applied to flights in interplanetary and interstellar space. Far from a large celestial body, the action of the forces of attraction of distant stars and planets will be so weak that the effect of weightlessness will arise. About how to deal with this, we have repeatedly read in science fiction novels. Space stations in the form of a torus (donut) will begin to spin around a central axis and create an imitation of gravity using centrifugal force. True, to create the equivalent of gravity, it is necessary to set a torus diameter over 200 m. There are other problems associated with artificial gravity. So this whole thing is a distant future.

When asked why objects and cosmonauts appear in a state of weightlessness under conditions of a spacecraft, many people give the following answer:
1. There is no gravity in space, so they do not weigh anything.
2. Cosmos is a vacuum, and there is no gravity in a vacuum.
3. The astronauts are too far from the surface of the Earth, so that the force of its attraction can act on them.

All these answers are wrong!
The main thing to understand is that there is gravity in space. This is a fairly common misconception. What keeps the moon in its orbit around the earth? The force of gravity. What keeps the Earth in orbit around the sun? The force of gravity. What prevents galaxies from flying apart? The force of gravity.

Gravity exists in space everywhere!
If you built a 370 km (230 miles) high tower on Earth, approximately like the height of a space station orbit, the force of gravity acting on you at the top of the tower would be almost the same as on the surface of the earth. If you decided to make a move from the tower, you would rush to Earth just as Felix Baumgartner is going to do later this year when he tries to make a jump from the edge of space. (Of course, we do not take into account the low temperatures that will instantly freeze you, or the lack of air or aerodynamic resistance will kill you, and falling through the layers of atmospheric air will cause all parts of your body to experience what it means to "tear off three skins ". And besides, a sudden stop will also cause you a lot of inconvenience.)

Yes, so why don't the space orbital station or satellites in orbit fall to Earth, and why do the cosmonauts and the objects around them inside the International Space Station (ISS) or any other spacecraft seem to be floating?

It turns out that it's all about speed!
The astronauts, the international space station itself (ISS) and other objects located on earth orbit do not float - in fact, they are falling. But they do not fall to Earth because of their enormous orbital speed. Instead, they "fall around" the earth. Objects in Earth orbit should move at a speed of at least 28.160 km / h (17,500 mph). Therefore, as soon as they are accelerated relative to the Earth, the force of gravity of the Earth immediately bends and leads the trajectory of their movement downward, and they will never overcome this minimum of approach to the Earth. Since the astronauts have the same acceleration as the space station, they experience a state of weightlessness.

It happens that we too can experience this state - briefly - on Earth, at the time of the fall. Have you ever been on a roller coaster ride, when right after passing the highest point (top of the hill), when the cart starts to roll down, your body lifts the seat up? If you were in the elevator at the height of a hundred-story skyscraper, and there was a cable break, then while the elevator fell, you would float in zero gravity in the elevator car. Of course, in this case the final would be much more dramatic.

And then, you probably heard about an airplane providing a state of weightlessness ("Vomit Comet") - an airplane KC 135, which NASA uses to create short-term states of weightlessness, train cosmonauts and test experiments or equipment in zero gravity (zero-G) as well as for commercial flights in zero gravity, when the plane flies along a parabolic trajectory, as in a roller coaster ride (but at high speeds and at high altitudes), passes through the top of the parabola and rushes down, then t crash are weightless conditions. Fortunately, the plane goes out of a dive and leveled.

However, let's go back to our tower. If instead of an ordinary step from a tower you had made a jump from a run, your forward energy would take you far from the tower, but at the same time, gravity would have blown you down. Instead of landing at the base of the tower, you would land at a distance from it. If during a run you increased your speed, you could jump further from the tower before you reached the ground. Well, if you could run as fast as a reusable spacecraft and the ISS orbit around the Earth at a speed of 28.160 km / h (17,500 miles per hour), then your arc trajectory would make a circle around the Earth. You would be in orbit and experience a state of weightlessness. But you would fall without reaching the surface of the earth. True, the suit and supplies air suitable for breathing, you would still need. And if you could run at a speed of about 40.555 km / h (25,200 miles per hour), you would jump out of the earth immediately and start spinning around the sun.

The International Orbital Space Station, the space shuttle ("Space Shuttle"), as well as satellites, are specially designed to remain in orbit without falling to the ground or falling into space. They complete a full orbit around the earth approximately every 90 minutes.

Therefore, when you are in orbit, you are in a state of free fall and experience weightlessness.

NOW YOU KNOW EVERYTHING !!
thanks for attention.

Universe Today || Original version"
Most of our regular readers understand why it seems that astronauts and objects on the International Space Station constantly swim from one place to another, at the same time there are misconceptions and preconceived opinions on this issue that are far from the truth and do not coincide with our classical understanding. physics! ..
   This video allows us to get acquainted with some pretty
   funny ideas of people about the conditions of weightlessness on board the orbital spacecraft and shows why, in fact, astronauts seem to us weightless.
   By the way, let's talk about this: When asked why objects and astronauts in a spacecraft appear to be in a state of weightlessness, many people give this answer: 1. There is no gravity in space, so they do not weigh anything. 2. Cosmos is a vacuum, and there is no gravity in a vacuum. 3. The astronauts are too far from the surface of the Earth, so that the force of its attraction can act on them.
   All these answers are wrong! The main thing to understand is that there is gravity in space. This is a fairly common misconception. What keeps the moon in its orbit around the earth? The force of gravity. What keeps the Earth in orbit around the sun? The force of gravity. What prevents galaxies from flying apart? The force of gravity.
   Gravity exists in space everywhere! If you built a 370 km (230 miles) high tower on Earth, approximately like the height of a space station orbit, the force of gravity acting on you at the top of the tower would be almost the same as on the surface of the earth. If you decided to make a move from the tower, you would rush to Earth just as Felix Baumgartner is going to do later this year when he tries to make a jump from the edge of space. (Of course, we do not take into account the low temperatures that will instantly freeze you, or the lack of air or aerodynamic resistance will kill you, and falling through the layers of atmospheric air will cause all parts of your body to experience what it means to "tear off three skins ". And besides, a sudden stop will also cause you a lot of inconvenience.)
   Yes, so why don't the space orbital station or satellites in orbit fall to Earth, and why do the cosmonauts and the objects around them inside the International Space Station (ISS) or any other spacecraft seem to be floating?
It turns out that it's all about speed! The astronauts, the international space station itself (ISS) and other objects located on earth orbit do not float - in fact, they are falling. But they do not fall to Earth because of their enormous orbital speed. Instead, they "fall around" the earth. Objects in Earth orbit should move at a speed of at least 28.160 km / h (17,500 mph). Therefore, as soon as they are accelerated relative to the Earth, the force of gravity of the Earth immediately bends and leads the trajectory of their movement downward, and they will never overcome this minimum of approach to the Earth. Since the astronauts have the same acceleration as the space station, they experience a state of weightlessness.
   It happens that we too can experience this state - briefly - on Earth, at the time of the fall. Have you ever been on a roller coaster ride, when right after passing the highest point (top of the hill), when the cart starts to roll down, your body lifts the seat up? If you were in the elevator at the height of a hundred-story skyscraper, and there was a cable break, then while the elevator fell, you would float in zero gravity in the elevator car. Of course, in this case the final would be much more dramatic.
   And then, you probably heard about an airplane providing a state of weightlessness ("Vomit Comet") - an airplane KC 135, which NASA uses to create short-term states of weightlessness, train cosmonauts and test experiments or equipment in zero gravity (zero-G) as well as for commercial flights in zero gravity, when the plane flies along a parabolic trajectory, as in a roller coaster ride (but at high speeds and at high altitudes), passes through the top of the parabola and rushes down, then t crash are weightless conditions. Fortunately, the plane goes out of a dive and leveled.
However, let's go back to our tower. If instead of an ordinary step from a tower you had made a jump from a run, your forward energy would take you far from the tower, but at the same time, gravity would have blown you down. Instead of landing at the base of the tower, you would land at a distance from it. If during a run you increased your speed, you could jump further from the tower before you reached the ground. Well, if you could run as fast as a reusable spacecraft and the ISS orbit around the Earth at a speed of 28.160 km / h (17,500 miles per hour), then your arc trajectory would make a circle around the Earth. You would be in orbit and experience a state of weightlessness. But you would fall without reaching the surface of the earth. True, the suit and supplies air suitable for breathing, you would still need. And if you could run at a speed of about 40.555 km / h (25,200 miles per hour), you would jump out of the earth immediately and start spinning around the sun.
   The International Orbital Space Station, the space shuttle ("Space Shuttle"), as well as satellites, are specially designed to remain in orbit without falling to the ground or falling into space. They complete a full orbit around the earth approximately every 90 minutes.
   Therefore, when you are in orbit, you are in a state of free fall and experience weightlessness.