Believe it or not, even space contains copious amounts of pollution. An estimated 4 million pounds of space debris — nuts, bolts, metal and carbon, even whole spacecraft — currently orbit the Earth, threatening satellites, communication and even the lives of our astronauts. This computer-generated Nasa graphic shows objects of space junk in Earth’s orbit that are currently being tracked.
Space debris , also known as orbital debris , space junk , and space waste , is the collection of objects in orbit around Earth that were created by humans but no longer serve any useful purpose. These objects consist of everything from spent rocket stages and defunct satellites to erosion, explosion and collision fragments. As the orbits of these objects often overlap the trajectories of newer objects, debris is a potential collision risk to operational spacecraft.
Space debris is a growing problem in many orbits despite international debris mitigation guidelines and policies. While this space environmental issue has been discussed and studied for years, many critical parameters continue to increase. For example, the number of significant satellite breakup events has averaged about four per year. Removing large amounts of material already in orbit has been a major issue for debris mitigation strategies because a large object, like a satellite or spent rocket stage, is not only more likely to be involved in an accidental collision due to its large collision cross-section but the large mass has the potential to be the source for thousands and thousands of smaller, but still dangerous, debris if involved in a collision.