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Paul M. Sutter is an astrophysicist at SUN Stony Brook and the Flatiron Institute, host of “Ask an astronaut” and “Space radio, “and author of”How to die in space. ”Sutter contributed this article to The expert voices of Space.com: Op-Ed & Insights.
There are over 20,000 known and tracked space debris orbiting the Earth, each moving at approximately 15,000 mph (24,000 km / h). They pose a risk to future space missions, and no one bother to clean them up. Why? Because it’s too hard.
In the early 1960s, the US military wanted to devise a new way to communicate with its forces around the world. If an enemy cut submarine cables, they could only rely on radio signals emitted by the ionosphere, which was not a reliable method. The Cold War Era Solution? A program called Project West Ford, a plan to launch 480 million tiny shards of copper needles into space, giving Earth an artificial ionosphere and a reliable means of communication.
After the first batch was successfully launched, the program was canceled. One of the reasons was the accelerated development of communication satellites. The other was that everyone realized that sending countless random pieces of garbage into space was probably a bad idea.
Related: How does tiny space debris cause incredible damage?
Since then, the amount of space waste has only grown. In Earth orbit, there are over 23,000 objects larger than about 4 inches (10 centimeters), another half a million objects larger than about 0.4 inches (1 cm) and maybe 100 millions smaller than that, according to NASA. And there’s all kinds of stuff up there: dead spaceships, depleted rocket boosters, gear lost in space missions (including a glove, camera, blanket, key, and sort of , a toothbrush), random pieces of destroyed material, paint stains, bits of metal, frozen rocket fuel, and lots of screws and bolts.
Space becomes messy and makes life dangerous.
Coming in!
On April 24, 1996, the United States Ballistic Missile Defense Organization used a Delta II rocket to launch an infrared surveillance satellite into orbit. About a year later, Lottie Williams of Tulsa, Oklahoma was going about her own business in a park when she was hit in the shoulder by a six-inch-long piece of fiberglass and aluminum. A few minutes later, other pieces of the second stage of this Delta II rocket crashed a few hundred kilometers away.
Williams became the first (and so far the only) person to be struck by falling space debris. But an estimated 100 tonnes of space waste reaches the Earth’s surface every year (although most of it falls into the ocean and poses no risk to humans).
Related: How are asteroids, space weather and space debris detected before they reach Earth?
And there’s more. In 2007, China tested its anti-satellite technology, launching a huge hyperspeed bullet at a weather satellite. The test worked and created over 3,000 pieces of tracked scrap in orbit. In 2009, a (functional) Iridium communications satellite was supposed to pass silently alongside a (dysfunctional) Russian military Kosmos satellite with nearly 600 meters to spare. This is not the case, and this event triggered another avalanche of 2,000 debris.
About once a year, the International Space Station must maneuver to avoid hazardous waste while astronauts hide safely in a Soyuz capsule. The Space Shuttle collected holes and craters in its windows, radiators, and thermal tiles in collisions with… mostly paint chips.
Despite their small size, the incredible speed of unwanted space objects gives them a serious punch, creating a very real risk for future space missions. With the launch of mega-stellations of broadband Internet satellites like SpaceX, OneWeb and Amazon, many are rightly concerned about the advent of “Kessler syndrome”, when enough debris causes enough collisions to trigger even more debris, cascading to the point that Earth’s orbit is a dangerous and unusable wasteland.
Laser brooms, boosters, nets and harpoons
Unfortunately, private companies and national governments are slow to act. Most of the effort is focused on mitigating and avoiding the generation of space waste in the first place. For example, rockets must use all of their fuel and reagents, in order to minimize the risk of an unexpected explosion. And when satellites reach the end of their life, they can either desorbit and (hopefully) burn up in the atmosphere, or, if high enough, push themselves into “graveyard orbit” by hundreds. miles above all that is useful.
While these mitigation strategies can help control the spread of space waste, they do nothing to clean up what’s already there. Earth’s own atmosphere will do some of the work because it drives everything in low earth orbit, but depending on the orbit, this process can take anywhere from a few months to a few decades.
Space agencies and private companies have come up with a variety of cleaning ideas. Special missions could push other satellites into the atmosphere or into the graveyard, using technology as old as civilization itself: harpoons and nets. Other plans call for lasers on the ground to heat one side of a satellite, causing it to shift orbit and become stuck in Earth’s atmosphere.
But aside from the ground laser, amusingly dubbed a “laser broom,” all the proposals call for the launch of new satellites, making satellite cleaning uncomfortably expensive. In addition, there is also the fact that any “satellite cleaning” technology automatically becomes “removing an enemy’s satellite from the sky” technology. This means that any proposal evolves rapidly in the murky waters of defense, international diplomacy and the militarization of outer space.
Our best strategy right now is to track, watch and warn, using a network of ground and satellite observatories, and keep our fingers crossed.
Learn more by listening to the episode “Who’s going to clean up all this space junk?” “ on the “Ask A Spaceman” podcast, available on itunes and askaspaceman.com. Ask your own question on Twitter using #AskASpaceman or by following Paul @PaulMattSutter and facebook.com/PaulMattSutter.
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