How many satellites orbit Earth?

Lots! And it depends on what you mean by a satellite. Usually we mean objects made by humans, fragments of metal, paint, tools, water ice and other odds and ends that are jettisoned or accidentally leave a Shuttle or rocket. The Cheyenne Mountain Operations Center of the U.S. Space Command (https://www.cheyennemountain.af.mil/boxscore.htm) gives a 'box score' of the total numbers of space vehicles and satellites it is currently tracking. As of December 2002, there were a total of 9,013 objects of which 169 were satellites and 6078 were classified as manmade debris including rocket bodies.

Space Command has an on-going program to track all artificial 'satellites' larger than a few inches, and keeps an updated catalog of these objects along with predictions for their decay during each 60-day period. For example, STS-113 launched on November 24, 2002 is NORAD Catalog Object 27556. Although STS-113 eventually landed, it left behind various types of debris. The orbits of this debris constitute 'artificial satellites', and when added to all the other junk up there, pose a significant hazard to further space activities.

By various accounts there are over 100,000 objects larger than 1/2 inches that have been tracked by NORAD in orbits that are mostly below 1,200 miles. Some of this material travels at speeds of up to 30,000 miles per hour. These include the debris from over 130 rocket and satellite explosions. In October 1999, the International Space Station had to be moved out of the way of a piece of orbiting junk that was headed right for it. Similar maneuvers have also taken place with the Space Shuttle.

This answer was updated in 2011. See my books: The Astronomy Cafe (1998) and Back to the Astronomy Cafe (2003) for more FAQs in printed form. Author: Dr. Sten Odenwald, Copyright 2011

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