Why are astronauts weightless in the space? Is it because they are beyond the pull of gravity?

Newton would not agree on this. Nor would anyone else, because the Earth’s gravity extends far out into the deep space. On the other hand, circling above the Earth spacecraft sometimes climbs no higher than 250 kilometers. At altitudes as low as this, the vehicle and its occupants are still very much held in the planet’s grip. Given this fact, why don’t they feel the pull of gravity which obviously is the source of weight?
The answer has a bit of surprise to offer. The fact is that orbiting spacecrafts don’t actually fly around the Earth. They fall – and continue to do so for days, months or years depending upon their altitude. Moving like a cricket ball that has been hit skyward for six, a spaceship no sooner reaches its apogee (highest point) in the space than it begins to drop back to the Earth. However, because of its speed and trajectory it never actually reaches the ground. The reason is that the Earth below constantly curves away from it. Hence, the spaceship’s circular or elliptical plunge never comes to an end. But why should this produce weightlessness?

Here’s why. The sensation of weight we experience daily is not only due to the tug of gravity but also to our constant resistance to its pull. Were you to remove the supporting ground or floor beneath your feet, you would feel your weight begin to disappear as you start falling. Assuming that air resistance did not retard your plunge, you would surrender completely to gravity’s pull and become weightless.

To get the feel of this condition during training, astronauts ride in airplanes that are flown in large ballistic arcs. These practice sessions are brief, but they do create – if only for a few seconds – the buoyancy the astronauts will feel when gliding through their orbits in the space.

Additional reading:
Weightlessness (Wikipedia)

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