Trapped on Planet Earth

James Eckstein | Contributor

(Photo Reid Wiseman, NASA)

As the possibility of a manned mission to Mars becomes more and more plausible, scientists may soon be presented with another issue that could further complicate their journey. The amount of space debris orbiting the Earth is growing at such a rate that it may soon become impassable for spacecraft. But what is space debris and what is its importance today and its significance for residents of Earth?
There are a lot of objects orbiting the Earth, so how is space debris classified? Space debris, or often called space junk, is the term used to describe any man-made object in orbit that no longer serves any useful function. The size of this debris can range anywhere from out of commission satellites the size of school busses down to the smallest of chips of paint. NASA has currently tracked just over 20,000 pieces that are larger than a standard size softball and over 500,000 pieces the size of a dime or larger. However, there are millions more pieces of debris that are too small to be tracked.
Almost all space debris will come from one of three sources; collisions, erosion, or decommission. The largest of debris will result from the latter, simply old equipment that no longer serves any purpose. There are currently no viable means of returning this equipment back to Earth to be properly disposed of. Erosion is the wear and tear of equipment in space from various sources of radiation and impacting micro particles. This leads to the very tiny non-traceable debris such as paint chips. The remainder of space debris comes from collisions between active equipment and space particles or ironically, other pieces of space debris.
All space debris orbiting the Earth is contained in one of two different layers, either geosynchronous Earth orbit (GEO) or low Earth orbit (LEO). GEO takes place approximately 36,000 kilometers above mean sea level. This zone typically contains older derelict satellites or decommissioned equipment. LEO is the orbit around the Earth with an altitude of 2,000 kilometers or less.
It is almost exclusively only space debris found in LEO that poses concerns for scientists as this is the area where most vital satellites function and where all manned missions occur. Astronauts aboard the International Space Station are constantly tracking and staying alert for debris. Even the smallest of debris can travel with speeds up to 28,000 kilometers per hour and cause substantial amounts of damage, potentially risking the safety of astronauts aboard. NASA and the Department of Defense can track space debris to approximately 2 inches in size, giving astronauts enough time to take evasive action. Currently there are virtually no means of getting rid of any space debris in either orbit which may lead to a phenomenon known as the Kessler syndrome.
Also called the Kessler effect, the Kessler syndrome is a theory created by NASA scientist Donald J. Kessler in 1978. He stated that if we continue to release objects into orbit with no means of disposing of them, space debris in LEO will continue to grow as more and more collisions occur. These collisions will create more space debris that will then in turn result in even more space debris through more collisions. Kessler then stated that if these collisions continue to grow at such a rate that it would eventually create a field of space debris that covers the entirety of LEO. Not only could this field stop future spacecraft and equipment from ever leaving Earth’s orbit, but it may also entirely disrupt global communication for everyone on Earth. This could result in massive losses in internet and telecommunications on a global scale.
Looking back, NASA and others have realized that they did not plan far enough into the future and are now starting to face the consequences of putting so much equipment into space so quickly without any plans of disposing of it properly. While they have recently started working on projects to try and reduce the amount of debris, some such as Kessler believe it is already too late.