Why do astronauts feel weightless when they are in orbit?

Answer 1

True "zero gravity" occurs for orbiting spacecraft because the vehicle is in effect in "freefall" around the planet : although gravity is trying to pull it down, its horizontal motion carries it on an arc past the planet.

For spacecraft sufficiently far from Earth (several thousand miles), there is imperceptibly low gravity. The acceleration force gravity exerts is reduced as the square of the distance from the center of gravity. While enroute to the Moon, Apollo astronauts reached locations where the gravity from the Earth and Moon were almost exactly opposite and tended to cancel each other. When spacecraft approach the Moon or Earth, local gravity begins to exert a larger force, and unless an orbit is achieved as above, it will be dragged down to the surface or into the atmosphere.

*Technically, the virtually imperceptible force experienced is called "microgravity" because the net forces of gravity from the Earth, Moon, and Sun still affect objects in orbit.

Answer 2

Weight is the force you feel because of the "pull" of gravity on your body.

A spacecraft stays in orbit because two opposing forces are in balance (equal). As a result of rotating around the Earth the spacecraft wants to fly off into space. Think of swinging a ball around and around on a string. If you release the string the ball flies away. In the case of an object in orbit, Earth's gravity acts like the string holding the object, preventing it from flying off into space. The object stays suspended in the orbit because the force due to it's rotation, that would otherwise cause it to fly off, is exactly contracted by gravity. One force neutralizes the other, thus the object and everything inside it feels no force on it at all.

Answer 3

True "zero gravity" occurs for orbiting spacecraft because the vehicle is in effect in "freefall" around the planet : although gravity is trying to pull it down, its horizontal motion carries it on an arc past the planet.

For spacecraft sufficiently far from Earth (several thousand miles), there is imperceptibly low gravity. The acceleration force gravity exerts is reduced as the square of the distance from the center of gravity. When spacecraft slow down or approach the Earth, gravity begins to exert a larger net force.

Answer 4

there are not reaction forces on them

Answer 5

because you have no gravity