Space Debris

When it comes to the topic of space debris, the adage that “One man's trash is another man's treasure” springs to mind. Known variously as space junk, space objects, orbital debris, and space waste, the term space debris refers collectively to the wide assortment of human-made objects found in orbit around the Earth and for which there is no current use. The Australian Space Academy distinguishes between two types of space debris: natural (such as meteoroids) and artificial (items that are the result of human agency). It is the latter that is typically denoted when invoking the term space debris.

The remains of Vanguard 1, a communications satellite launched into low Earth orbit (LEO) by the United States in 1958, was widely regarded as the oldest item of space debris in orbit as of 2010. Ranging from items the size of paint flecks to defunct satellites, there are likely tens of millions of items of space debris orbiting the Earth. Occasionally, such items reenter the atmosphere and plummet to the planet's surface—as was the case in July 2009 when a four-pound piece of extremely hot metal crashed through the roof and into the attic of a home in West Hull in the United Kingdom (UK). The story was updated in the London Mail Online several months later, when the property owners were subsequently contacted by staff of the Royal Air Force, who assured them that the item recovered from their home was most likely space junk that had been orbiting the planet for more than a decade. Such instances are rare because many items burn up upon reentering the atmosphere or fall harmlessly into the open sea or other unpopulated areas, as was the case when the National Aeronautics and Space Administration's (NASA's) Skylab station fell out of orbit in 1979 and distributed debris over western Australia.

The greatest risk such items pose is to functioning satellites, telescopes, and manned space stations or spacecraft—as was the case when astronauts aboard the International Space Station were “buzzed” by a roughly five-inch piece of debris in 2009. Such a collision would have wrought significant damage to the station as well as potential loss of life. As such, space debris is of major interest to the international community. That interest, however, assumes quite distinct forms: one that celebrates it and the other that sees it as a serious problem to be mitigated.

There are likely tens of millions of items of space debris orbiting the Earth, ranging in size from paint flecks to defunct satellites. Impacts with Earth are rare, as debris usually disintegrate upon reentering the atmosphere or drop into the sea or deserted areas.