How is a satellite placed in orbit and why it retains its position in space?

Answer 1

This can vary depending on the function of the satellite. In general, the satellite is launched by unmanned rockets or from the space shuttle payload bay at the correct altitude. After the satellite is released from the launch vehicle, the speed of a satellite is adjusted so that the rate at which it is being pulled back toward the earth is the same as the rate at which the earth is turning underneath it. So it is continually falling but not hitting the earth. This is what is also happening to the space shuttle when in earth orbit and the ISS.

Satellites in geostationary orbit - where they appear to remain over a single point on the earth - must have a circular orbit for this to occur. That is why they are placed over the equator. Any other orbit is elliptical in shape.

The problem that arises is that the earth is not perfectly round, even at the equator, and so the orbit of geostationary satellites must be adjusted every two weeks to compensate for this. The engines are remotely fired for the correct amount of time. When the fuel runs out, this can no longer be done.

Orbital mechanics is a complex and detailed concept to understand. See some of the Web Links to the left.

Answer 2

A satellite is placed in orbit by launching it into space using a rocket. Once in orbit, the satellite continues to maintain its position due to the balance between its velocity and the gravitational pull of the Earth. This balance causes the satellite to continuously fall towards the Earth while also moving sideways fast enough to miss the planet, following an elliptical path around it.

Answer 3

Although all satellites are constantly falling towards the Earth, they are moving across in a path that takes them beyond the Earth as they fall - so are literally falling all the time.

However, because the Earth's atmosphere does extend several hundred miles into space (as tenuous as it is), Satellites in low Earth orbit are all on orbits that will eventually result in the satellite burning up when they hit high enough atmospheric pressures.

This includes the International Space Station, which must be boosted up several times a year to prevent it from falling into the atmosphere.

When the air is so thin, however, the drag from the air is low, and there's nothing to slow a satellite down. In high orbits, such as Geosynchronous orbit, 22,300 miles above the Earth, there is absolutely no air, so the satellites will orbit for millions of years.

When the Space Shuttle wants to return to Earth, the crew turn it around and fire rockets to slow it down, so that it drops into the upper atmosphere and slows down the rest of the way for the return.
Same way as our moon stays up in space. They rotate around the earth with a certain speed, and there's nothing to slow them down, so they stay up there.

(The international space station however is closer to earth and loses speed due to friction with the atmosphere. Its has engines to keep it flying)
Satellites orbit Earth. To see how this works, imagine firing a cannon from the top of the mountain - the cannon ball will fall towards the Earth in a curve as it moves from the cannon. Now imagine a very high mountain and a powerful cannon so that the ball falls in a curve that follows the curve of the Earth; the ball will never reach the ground - it circles the Earth in free fall.

Answer 4

Tie a washer onto a piece of string and swing it in a circle over your head. Now in the case of the satellite, Earth is like your hand, gravity is like the string, and the satellite is the washer. The satellite is given a push at a specific speed at a certain distance from the earth in a direction perpendicular to the direction gravity wants to pull it, and the gravity causes the satellite to swing around the earth since it always pulls towards the center of the earth.

Answer 5

The satellites that "stay positioned" in the sky are called geostationary. The way it works is this. First, the satellite must be in orbit around the equator. Also, to stay in orbit around the earth, an object has to have some amount of motion. It's called orbital velocity. The farther out it is, the less orbital velocity it has to have because there is less gravitational effect in those higher orbits. At some point out there, the satellite will be moving at the same speed the earth is turning, and will appear from earth to be stationary. A satellite (sometimes called a "bird") won't be moving as we see it from here. We've parked a bird in geostationary orbit. Note: There is a slight "figure 8" motion to birds out there in those orbits. A link can be found below.

Answer 6

I am not completely sure but i think it is something to do with the speed of the satalite and how high up it is. That why they fire them up in shuttles and try to get the at the right speed for their orbits

Answer 7

There are two factors associated with the ability of a satellite to remain in its orbit about the earth. The first is that the satellite was accelerated a great deal by the launch vehicle. It was really moving when it was released into its desired orbit. The second factor is the gravitational attraction of the earth. Let's break it down a bit more.

If the gravity of the earth was not acting on the satellite, its speed would cause it to "fly off" on a tangent to its previous orbital path. You can picture this if you visualize a ball on a string being swing rapidly about an experimenter. If the string breaks or the person swinging the thing lets it go, the ball takes off in a straight line from the circle it has been moving in. The string in this experiment could be likened to the earth's gravity acting on a satellite and "holding it" on its orbital path.

Should we break it down one more time, the satellite moves just a tiny bit in the direction it is going, but is pulled a bit closer to earth by gravity. The satellite then moves a bit more in the "new" direction (a tangent to the orbital path), and the earth again pulls it in a bit. The result is that the sum of the two vectors (the satellite's inertia and the pull of gravity) results in an orbit about the earth. Each instant represents a tiny movement of the satellite on a tangent plus a tiny tug of gravity on the satellite to keep it on a curved path.

Answer 8

Any orbit is a balance between the speed of the object and gravity. Gravity pulls the satellite DOWN, but the object is going so fast that by the time it falls back to Earth, it has already gone so far "downrange" that the satellite has missed the Earth. And it keeps on missing!

That's why scientists call it "free-fall" rather than "weightlessness"; the satellite still has its normal weight, but is falling AROUND the planet.

Answer 9

It stays in the Earth's orbit because of Earth's gravity. The same way the moon is being pulled by Earth's gravity.

Answer 10

It attains a speed that keeps it from both falling back to earth and also keeps it from flying out of orbit and going into space.