Can Artificial satellites orbit forever

Answer 1

no they can not orbit forever. However, the time that a satellite will remain in orbit is dependent on altitude. Satellites in orbits above about 1500 miles will never decay and fall to Earth, in the expected lifetime of the solar system.

Satellites will not stay in orbit forever. How long they stay up depends on how high they are and the satellite's ballistic coefficient, or mass/frontal area. The drag from our atmosphere decreases with height. Satellites in low orbits, say 500 km, will decay in a few years. At 1000 km they will stay up perhaps a century. Above a few thousand km they would stay practically forever.

Proper disposal of spacecraft is important. A small piece of spacecraft or debris can continue to orbit for a long time, presenting a hazard to operating spacecraft.

Answer 2

A satellite (sometimes called a called a bird) can stay in orbit for either a long or a short time, depending on the nearness of the orbit to earth. What is called low earth orbit (LEO) is from about 160 to 2000 kilometers up. There is a tremendous amount of drag on anything below about 200 kikometers, though, and it isn't productive to put a bird up at anything less than that as it won't stay there long. Recall that the atmosphere of the earth doesn't abruptly "end" at a given point, but thins on a continuous basis until it's pretty much "all gone" at a given altitude. Above that altitude, if a satellite is in orbit, there will be no drag on it to slow it down and bring it back to earth. Below that altitude, the tiny bit of drag (or the large amount of drag if it's really low) will slow the object down and it will eventually suffer sufficient orbital decay so as to re-enter the atmosphere (and burn up, usually). We generally think of the atmosphere ending at about 100 kilometers (according to NASA), but there is some atmosphere above that altitude. The super thin hydrogen cloud that is outmost (the geochronosphere) extends to a thousand kilometers or more. It might be correct to say that permanent orbit (or at least very long term orbit) can be achieved by exceeding the 200 kilometer mark, and preferably by another hundred kilometers - or more. Wikipedia has a post on Low Earth orbit, and a link is provided. Why not surf on over and give it a quick read? It's got some good information, and it isn't rocket science. Well, actually it is, but the page isn't difficult to understand. Maybe just skim it to see what's up.

Answer 3

Yes there are ones orbiting the Moon, Venus, Mars, Jupiter and Saturn.