Since humans started launching rockets and other objects into space in the 1950s, orbital space debris has been slowly accumulating above our atmosphere. It’s a multinational problem that’s only getting worse-Russian scientists recently warned that the rise in space junk could provoke armed conflict in the near future. Here’s everything you need to know about our junkyard in the sky.
The Size Of The Problem
Estimated Figures as of July 2013
29,000 Pieces of debris the size of a softball a larger (≥ 10 cm)
670,000 Pieces of debris the size of a marble or larger (≥1 cm)
170 million pieces of debris too small to be tracked larger than 1 mm.
Where It Comes From
Dead satellites, the upper stages of launch vehicles, bits of discarded leftovers from separation, tiny flecks of paint, and even frozen clouds of water all remain in orbit high above Earth’s atmosphere.
Last year’s spaceX Falcon 9 explosion proved once again that space tech is far from perfect. For the first 50 years, the major source of all space junk has come from object that exploded by accident.
Space debris travels at 28,000 kilometres per hour (17,500 miles per hour). When it crashes into other debris-and occasionally even functioning spacecraft more debris is generated. In 2009, and inactive Russian satellite collided with a functioning U.S. Iridium commercial satellite, generating more than 2,000 pieces of debris.
Significant amounts of debris also introduced into orbit by military tests. In 2007, China added 3,000 pieces of space junk inventory when it used a missile to blow up an old weather satellite during an anti-satellite test.
Protecting Orbital Assets
The U.S. Department of Defence (DoD) maintains a satellite catalogue of objects in Earth orbit that are larger than a softball. Using its space surveillance Network, the DoD also tracks objects as small as 5 centimetres (2 inches) in diameter in low Earth orbit, and about 1 metre (3.2 feet) in geosynchronous orbit. There are currently about 15,000 officially cataloged objects in orbit.
For trackable objects, NASA has established guidelines to assess whether the threat of a close pass is high enough to warrant evasive action. The ISS has made changes to its flight path (usually once a year) when it is projected to come within a few kilometres of a large piece of debris.
For smaller space debris that is too minuscule to track, debris shields are effective in withstanding impacts. Most satellites and spacecraft now have them, and NASA”s hypervelocity Impact Technology Facility in Texas is testing new protective materials all the time. The International Space Station (ISS) is the most heavily shielded spacecraft In orbit.
Falling Back To Earth
Debris that returns to Earth often burns up in our atmosphere, but some larger objects occasionally reach the ground intact. By NASA’s account, an average of one piece of space debris has fallen back to Earth each day for the past 50 years. Here are some of the more notable space debris events in history.
August 29, 1965
The Gemini V spacecraft, launched nine days earlier, reentered the atmosphere and crashed into the Atlantic ocean. Several spheres turned up in Western Australia, one of which was identified as a tank used for drinking water in the spacecraft.
July 11, 1979
Weighing 70,000 kg (77 turns), the first and only U.S. space Station, skylab, came to a premature end when it plummeted through the atmosphere, sending debris over an area stretching from the Southeastern Indian Ocean to portions of Western Australia.
Jan. 24, 1978
A secret Soviet Navy satellite called Cosmos 954, launched on Sept. 18, 1977, spiraled out of control and reentered the atmosphere over Canada, shedding debris across the frozen Canadian Arctic. The satellite featured a compact nuclear reactor, making its reentry one of the most frightening to date.
Jan. 22, 1997
Tulsa, Oklahoma resident Lottie Williams Reported being struck on the shoulder by falling debris while taking a walk. The object was later confirmed to be part of the fuel tank of a Delta II rocket. and more debris was recovered hundreds of kilometres away-in Texas.
June 4, 2000
The Compton Gamma Ray Observatory was intentionally deorbited due to a crippled gyroscope. Roughly 6,000 kg (6 tons) of debris splashed down into the Pacific Ocean southeast of Hawaii.
Jan. 21, 2001
A Delta 2 third stage reentered the atmosphere in two stages. It’s titanium motor casing weighing around 70 kg (154 lbs), landing in Saudi Arabia while a titanium pressurant tank and its main propellant tank landed in Texas.
March 23, 2001
Russia’s 130,000-kg (143-tons) space station reentered Earth’s atmosphere above the Pacific Ocean near Fiji. Though most of it burned up in the atmosphere, about 1,500 fragments reached Earth’s surface.
Feb. 1, 2003
More than 84,000 pieces of shuttle debris were recovered across a 72,520 sq. km (28,000 sq. mi) area in eastern Texas and a western Louisiana in the aftermath of the Columbia Space Shuttle explosion.
March 27, 2007
Airborne debris from a Russian spy satellite was seen by the pilot of an Airbus A340 carrying 270 passengers while flying over the Pacific Ocean between Santiago and Auckland.
Feb. 20, 2008
The U.S. Navy intercepted its defunct spy satellite USA-193, sending a trial of debris that some amateur astronomers reported falling over the northwestern U.S. and Canada.
In 1995, NASA was the first space agency to issue guidelines for orbital mitigation. The agency’s approach encompasses of protocol such as reassurance of satellite reentry after mission life, and the capture and deorbit of derelict satellites, among others.
The goal of self-removal is to take debris out of harm’s way. Satellites would be moved to a graveyard orbit at the end of their lives, or space agencies would make a direct, controlled deorbit using a solar sail to steer.
The most comprehensive solution is also the most technically and financially challenging. External removal would involve sending a remotely controlled vehicle to rendezvous with the debris, capture it, and return it to a central station.