Earth Orbit?

Question

At what speed does a spacecraft or satillite normally orbit Earth? Can that be accelerated or decelerated? Why is the average speed used, as in what are the advantages?

Answer 1

they orbit the earth by the earth`s escape velocity they can accelerate but it will waste fuel , they cant deccelerate or they will be sucked down by the earth`s gravity

Answer 2

Low Earth Orbit speed is 17,500 miles per hour. The higher you go, the slower the orbital speed. Geostationary satellites at 22,000 miles altitude orbit at about 6,000 miles per hour. For circular orbits, there is only one speed for the altitude, or radius of the orbit. For elliptical orbits, the speed varies, but it varies in a regular periodic fashion between a high speed at the low point, called the perigee, and a low speed at the high point, called the apogee.

You cannot simply change your speed and expect to stay in the same orbit. The orbital altitude and speed are related. Changing your speed will change your altitude and changing your altitude will change your speed.

Paradoxically, slowing down causes you to fall to a lower orbit, where you have to be moving faster. You speed up as you "fall" to the lower orbit. The space shuttle uses small rockets to decelerate very slightly, which makes the orbit a little lower; just low enough to start skimming the upper atmosphere. From there, drag with the air slows it down more, which makes the orbit lower, which puts it in even denser air which slows it down more ... and so on. That is reentry.

Answer 3

It depends entirely on the height of the orbit, but it is always below the escape velocity (otherwise it would not be an orbit!)

Geostationary satellite have to travel at a precise speed and height over the equator - such that they travel 1 revolution of the Earth in 24 hours. This speed is 6,877 mph.

Answer 4

The speed depends on how high the satellite is. The relationship between speed and RADIUS (add in the radius of the Earth to the satellite's altitude) is:

s=sqrt(GM/r) where GM is the geocentric gravitational constant (3.986 x 10^5 km^3/sec^2) and r is the satellite's distance from the center of the Earth.

A geosynchronous satellite has a speed of around 3075 m/s, while a low orbiting reconaissance satellite has a speed of around 7450 m/s. The shuttle, being even lower than reconaissance satellites, has a speed of around 7730 m/s.

Answer 5

Approximately 18,000 mph...which is five miles per second. It used because that's what the laws of orbital mechanics dictate we use...we don't have a choice.

P.S. the precise speed one orbits at is dependant an the altitude of said orbital path. Again, it's all determined by the laws of physics...if you actually do speed up or slow down, your altitude will change to match your speed.