In 1957, Sputnik was launched into orbit as the world’s first artificial satellite.
Today, 64 years later, there are more than 1,000,000 objects larger than 1 centimeter floating around the Earth.
Almost all of those objects in orbit were not put there intentionally.
Learn more about space junk, the problem, and possible solutions, on this episode of Everything Everywhere Daily.
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Since 1957 humanity has been launching satellites into Earth orbit. It is estimated that in the last 64 years, almost 9,000 satellites in total have been put into orbit.
For the vast majority of the space age, there was never a plan for what would be done with satellites after their lifetime. They were launched without any thought as to how or if they would ever come down.
Of the 9,000 or so satellites, 5,000 are still in orbit. 2,000 are still in service, and 3,000 are dead.
These satellites are usually quite large. They can vary in size from a bus to a box, and they aren’t the real problem when it comes to space junk.
The big problem is debris. When you send up a rocket, there are all sorts of miscellaneous parts on the upper stage of the rocket that holds the satellite that will go into orbit along with it. This can include metal panels, bolts, screws, and even flakes of paint.
You’d think that given how big space is that space junk might not be a problem. As Douglas Adams noted:
“Space is big. Really big. You just won’t believe how vastly hugely mind-bogglingly big it is.”
Suppose you had a million pennies. That would be enough to easily fit in a minivan.
Now, let’s suppose you distribute those pennies all over the world, including the ocean and Antarctica.
Each penny would have 197 square miles of space, or a single penny would have a square which was 14 by 14 miles.
Factor in that the lowest Earth orbit is a sphere larger than the Earth, and that there is a vertical dimension where we could put pennies at different elevations, then it wouldn’t seem that space junk was a big problem.
If the object just sat there, there wouldn’t be a problem.
However, all of the junk isn’t just sitting there. It’s orbiting the Earth at extremely high speeds. Any piece of space junk is probably traveling at least 17,000 mph.
When something is traveling that fast, no matter how small it is, it can cause a great deal of damage. Moreover, everything is in a slightly different orbit. That means, over time, these orbits can cross, and the longer something remains in orbit, the greater the odds that those paths will eventually cross and things will smash into each other.
The things which are floating around in space include two cameras that got away from astronauts, pliers, a screwdriver, and a wrench, a full tool bag, garbage bags, a lens cap, a spatula, and microscopic flakes of rocket propellent. That is on top of all the rocket debris and dead satellites.
If a ship with astronauts were to be hit, it could lead to the deaths of the crew. If an important satellite were to be hit, it could lead to a loss of critical communications, GPS signals, or observing capabilities.
This isn’t just a theoretical problem. There have been cases of collisions in space.
The space shuttle had many tiny impacts from debris in space. On the seventh space shuttle mission in 1983, the front windshield was hit by a fleck of paint, which damaged the window. It looked very similar to what happens when a rock hits your windshield.
Damage to the shuttle’s heat tiles was so common that they eventually began flying the shuttle backward in space so the engines, which weren’t used during reentry, took most of the damage.
The shuttle Endeavour was hit by an object so large that its radiator looked like it was hit will a bullet.
The international space station has to move on average at least once a year, to avoid space debris.
The Soviet Kosmos 1275 satellite was hit by an object in 1981, which was believed to be the first case of a satellite being destroyed by space junk.
Perhaps the worst case occurred in 2009 when the Kosmos 2251 satellite, which was dead, smashed into the Iridium 33 satellite at a relative speed of 26,000 miles per hour.
These collisions and there have been several more, only make things worse. In the first case, 300 new objects were created from the collision, and in the second, there were suddenly thousands of new objects thrown off on different trajectories.
In 2007, the Chinese government did an anti-satellite missile test that blew up a satellite in space, creating tens of thousands of pieces of debris.
This problem of junk causing collisions, which then creates exponentially more junk, risks something called the Kessler Syndrome.
This was hypothesized in 1978 by NASA scientist David Kessler. He proposed that collisions could start a cascade of debris which would cause more collisions and even more debris, rinse and repeat.
If it was bad enough, it would render low earth orbit, which is where the majority of satellites operate, and where all current manned missions take the palace, would be totally unusable for generations.
To top it all off, the problem has been getting worse, not better over the last 10 years, as more and more satellites have put into orbit.
So, what can we do?
For starters, most satellites now have some sort of decommissioning plan. That means they carry enough fuel to force the satellite into reentry at the end of its life, or some other mechanism to cause it to come back to the atmosphere and burn up.
For example, Elon Musk’s SpaceX has put close to 1,000 satellites in orbit for their Starlink internet constellation. Each satellite, while small, has a small thruster to do small maneuvers of the satellite, and to deorbit it at the end of its lifespan.
One company called Tethers Unlimited has created a simple device which they call Terminator Tape, which is a long, thin 70-meter tether that can extend from a satellite to increase its drag, causing the satellite to reenter the atmosphere years or decades sooner than it otherwise would.
Most satellites in low earth orbit now have some sort of deorbiting strategy.
What about all the stuff that’s up there already?
One proposal is just to send up a tug with lots of propellant. It could move from orbit to orbit, rendezvousing with dead satellites, swallowing them up. When it’s full, it when then just deorbit itself and everything inside it.
Other proposals involve sending up tiny satellites to meet dead satellites, have them latch on, then deorbit them.
But what about the really small stuff?
Nothing has been done yet, but there are many ideas.
One Singapore company wants to send up giant solar-powered electromagnets. It would either get the debris to attach itself to the magnet, or alter its orbit enough to hasten its natural reentry.
Another proposal is to launch a giant foam ball that would expand once it was in a vacuum. The ball would passively smash into objects, either embedding them in the foam or slowing them down enough so they would deorbit faster.
Another proposal would fire a high-power laser from the Earth’s surface at space debris. By heating the object, especially a very small object, the radiating heat would cause the debris to change its orbit, again hastening the time it would take to reenter the atmosphere.
Other proposals involving harpoons and nets have been suggested as well.
Along with the various technical solutions, there also needs to be an international treaty governing space debris. Right now, there isn’t anything that legally deals with the problem. There would need to be a ban on anti-satellite tests in orbit, as well as a requirement that any satellite which is put into orbit has a built-in mechanism for deorbiting.
Over the next 10 years, the number of satellites in orbit is expected to quintuple. The issue of space debris is only going to become more important.
If we are to avoid a Kessler Syndrome type event, which would render parts of Earth orbit dangerous if not unusable, efforts will be needed to solve the problem quickly.