Space is enormous beyond imagination, but just as human-generated trash fouls the seemingly boundless vastness of our oceans, litter from human space exploration is contaminating our tiny corner of the cosmos. While naturally occurring asteroids can threaten our existence, space debris can damage spacecraft and satellites in orbit as well as pose a threat to our well-being on Earth.
Space exploration began when the Soviet Union launched the first satellite, Sputnik 1, in 1957, setting off a furious race to conquer and exploit the void above us. After six decades, it has been estimated that there were well over a million pieces of debris from exploded, crashed, or abandoned objects orbiting Earth, mainly satellites and satellite detritus.
These space-age flotsam travel at extreme speeds in orbit around Earth, threatening damage to exploratory missions and satellites. During the Space Shuttle program, which was suspended in 2011, spacecraft windows had to be replaced on several occasions because of damage they sustained from objects less than 0.04 inches in diameter. Space debris can also collide with other pieces of junk and create more dangerous fragments. The largest pieces of space junk could cause injury and damage on Earth if allowed to fall from orbit in an uncontrolled descent.
More remote, but potentially more devastating, is the threat posed by asteroids and other non-Earth objects (NEOs). Large numbers of these circle the sun, with a relative few coming close to Earth. In its distant past, Earth was twice devastated by huge asteroids with miles-wide dimensions, one 66 million years ago which famously ended the reign of dinosaurs, and one 3.2 billion years ago at the dawn of life on Earth. Fifty thousand years ago, a meteor crashed into our own state of Arizona, leaving a crater nearly a mile wide. In more modern times, much smaller asteroids, measured in feet, have caused injury and damage in Russia (2013) and Siberia (1908).
Scientists have put in place mechanisms and protocols for tracking space hazards, and they continue to improve systems to deflect or destroy objects that threaten orbiting spacecraft or Earth itself, but these systems are imperfect and incapable of eliminating all risks.
24/7 Tempo has researched 25 space objects that have some potential for doing damage to Earth or the use of the space around it.