Re: How often do satellites at Low Earth Orbit pass a stationary point on Earth

Hello, and good question. Satellites in low earth orbit take about 90 minutes to completely circle the planet. Their orbit takes them between 200 and 500 miles above the Earth’s surface, and they travel at about 17,000 miles per hour. The space shuttle orbits about an altitude of about 210 miles, so it, too, takes about 90 minutes to orbit the earth.

I am willing to bet that, since you saw a satellite pass twice within an hour, it was actually two different satellites in about the same orbit. According to U.S. Space Command there are over 8,000 objects in low earth orbit. However, not all of these are satellites. It also includes space junk, so on a dark night it should be possible to see many satellites in a short period of time.

There are other types of obits that a satellite can have, including a polar orbit, geosynchronous orbit, and elliptical orbit. A polar orbiting satellite travels in a north to south direction. Geosynchronous orbiting satellites can be found at altitudes of about 22,300 miles and circle the planet at such a speed that they would appear to be nonmoving (stationary). Elliptical orbiting satellites orbit in an ellipse shape with the Earth located at one of the two foci.

The Satellite Site is a great website (and where I found the information above) with animated graphics showing how each type of orbit looks, in addition to giving lots of other great information.

Hope this helps!