What Keeps a Satellite In Space?

Answer 1

Once a satellite is launched into orbit, the force of gravity tends to pull it toward the Earth. But by moving fast enough, it falls in a curved path and circles the Earth. So orbit is something like a controlled fall. If a satellite does not move fast enough, it will eventually spiral closer to the Earth and burn up in the Earth's atmosphere.

The same balance of gravity and speed keeps the moon and the International Space Station in orbit.

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Answer 2

A satellite is only able to stay in space when there is a balance between the centripetal force and the centrifugal force. If these forces were not balanced, the satellite would crash to the earth.

Answer 3

An orbiting satellite stays in orbit because it has sufficient horizontal velocity to oppose the pull of gravity. The same forces keep the Moon orbiting the Earth and the Earth orbiting the Sun.

You could say that the forward velocity of the satellite causes it to fall "past" the Earth as it is pulled by gravity. The outward vector of its motion balances the gravitational acceleration trying to pull it down. The combination of these forces keeps it moving around the Earth. Because there is very little friction in space, an orbiting satellite may maintain its forward speed for a long time, even without additional thrust being applied.

An orbit as a curved path

The satellite's velocity (the speed at which it would travel in a straight line) is opposing the gravitational pull between the Earth and the satellite. Satellites never fall into the Earth because the Earth is round and curves. The Earth curves approximately 5 meters downward for every 8000 meters along its horizon. In order for a satellite to successfully orbit the Earth, it must travel a horizontal distance of 8000 meters before falling a vertical distance of 5 meters.

When launched at a high speed (escape velocity), a projectile will fall towards the Earth with a trajectory which matches the curvature of the Earth. As such, the projectile will fall around the Earth, always accelerating towards it under the influence of gravity, yet never colliding into it since the Earth below is constantly curving away at the same rate. Such a projectile is an orbiting satellite.

Answer 4

The satellite's forward motion, and gravity.

Orbiting satellites are constantly falling, drawn toward the Earth by gravity. But since their speed makes them fall "past" the Earth, they continue going around. If they are slowed down (by friction or thrust), they will fall back to Earth like any other object. Fortunately there is so little matter at orbital altitudes (above 50 miles / 80 km) that most satellites can stay in orbit for many years without slowing very much.

(* For a simple analogy to orbiting, place a ball or other object at the end of a long elastic string and twirl it around. The string is like gravity, pulling on the ball and keeping it from flying away. But if you spin the ball fast enough, the ball stays out at the end of the string, keeping it stretched even though the elastic tries to pull the ball in.)

Answer 5

Earth's gravity allow satellites to stay in orbit.

Answer 6

As the satellite orbits a planet, its centripetal acceleration and the gravitational acceleration balance each other out to keep it in orbit. The height of its orbit depends on its speed.

Answer 7

The gravity of the parent body keeps the satellite in orbit.

Answer 8

for communication