Satellite Burning: Why Does It Occur?

[Himal kharel]

Why does a satellite burns if it falls from orbit to atmosphere? BUT not when it is launched ffrom surface to orbit, ALTHOGH they pass through the same atmosphere

 

[DaveC426913]

Why does a satellite burns if it falls from orbit to atmosphere? BUT not when it is launched ffrom surface to orbit, ALTHOGH they pass through the same atmosphere

Going up, it does not reach a very high velocity until well out of the atmosphere.
Coming down, there is nothing to slow it down from its 25,000mph speed except the atmo shockwave.

Also, going up, it is aerodynamically sound inside a rocketship, whereas coming down it is not protected and covered in delicate equipment.

 

[rcgldr]

When an object is put into orbit, a lot of that speed is obtained after the object has gone past the main part of the atmosphere. Since the ratio of fuel to payload is so high to get an object into orbit, even objects like the Space Shuttle rely on the atmosphere to slow them down again as opposed to carrying so much fuel that they can slow down to nearly the speed they used when going through the atmosphere.

Most low orbiting objects are in the next to outer layer of atmosphere called the thermosphere. The atmosphere there is very thin, but just enough to slow a low orbiting object down so that it eventually burns up in the lower layers of the atmoshpere, and this provides a way to keep from cluttering low Earth oribital area's with space junk. In the case of the space station and the Hubble telescope, these need an occasional boost from space shuttles (there may be a robotic space vehicle used to do the last Hubble service) in order to maintain their orbit.

The speed of most of these low orbit objects is around 17,500 mph. The fastest rentry speed of a manned spacecraft was Apollo 10, something like 24,790 mph. Fastest unmanned reenty of a man made satellite was a sample return capsule from Stardust, 29,000 mph (it used parachutes similar to the old Apollo missions for a safe "landing").