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The 1950s was the dawn of the space age. Since then, we’ve launched thousands of rockets and satellites into space. Many of them are still there, orbiting the Earth. As long as we’ve explored space, we’ve also created a mess. Thousands of pieces of debris from all the rockets and satellites we’ve launched over the years are orbiting our planet. Space junk, space waste, or space debris are pieces of machinery or other material left in space by humans. Space waste can consist of big objects like satellites that have failed or left in space when their mission ended. It can also include smaller things like flecks of paint fallen off a rocket. We’ve left much of our space waste on the moon too.
Today, around 2,000 active satellites are orbiting the Earth. But left to litter space is also 3,000 dead ones. Moreover, approximately 34,000 pieces of space waste greater than 10 cm are orbiting the Earth, along with millions of smaller pieces that could cause a disaster if they hit something else. Space waste is a major problem because it is likely to hit other objects, especially satellites.
All the waste in space comes from satellites and rockets launched by us. The debris stays in orbit around the Earth until they re-enter the atmosphere. Objects at a lower orbit, such as a few hundred kilometers away, can return quickly. They mostly re-enter the atmosphere after a few years and burn up on their descent, so they don’t actually reach the Earth’s surface. But satellites left at altitudes of 36,000 km or higher can continue to orbit the Earth for hundreds to thousands of years before returning.
Some space junk even results from collisions between two satellites. On collision, they can break apart into thousands of tiny pieces. Countries including the USA, China, and India have used missiles to blow up their own satellites.
Fortunately, space waste is not a significant challenge in our exploration efforts. However, it does pose a considerable risk to other satellites in orbit. These satellites have to maneuver to stay out of the way of all space junk. If a piece of space junk hits a satellite, it can potentially get damaged or destroyed. Satellites, including the International Space Station (ISS), where astronauts live, perform a hundred collision avoidance maneuvers a year to avoid getting hit by space waste.
Fortunately, collisions between space waste and satellites are rare. In March last year, a Chinese satellite broke into pieces after a collision with space waste. The only accident that happened before that was in 2009 when space junk collided with and destroyed a satellite. Space waste is not a problem for us when it comes to exploring space beyond the Earth’s orbit.
The United Nations has asked all countries to remove their satellites from orbit within 25 years after they’ve completed their mission. However, this law is tricky to enforce. Satellites can, and often do, fail. If they fail, it gets pretty difficult to remove them from orbit. This challenge has led many companies worldwide to develop solutions to space waste.
One of these solutions includes removing dead satellites from orbit by dragging them back into the atmosphere. Once they enter the atmosphere, they will burn up and disintegrate. The solution involves catching the satellite in a huge net using a harpoon. Some of the solutions also include using lasers to heat up the satellite. The heat increases its atmospheric drag, causing it to fall out of orbit and into the atmosphere.
However, all these methods are useful only for satellites. It is almost impossible for us to pick up smaller pieces of debris like pieces of metal and paint flecks. We just have to wait for those to enter Earth’s atmosphere naturally.
In 1978, NASA scientist Donald Kessler proposed a theory of what would happen if there was too much space waste. We now know this theory as the ‘Kessler Syndrome’. The Kessler Syndrome says that too much space waste orbiting the Earth could result in a chain reaction where they collide and create smaller pieces of more junk. This could create so much space waste that it interferes with the Earth’s orbit and makes it unstable.
Although this is an extreme situation and very unlikely to happen, some experts worry that a similar situation might be a problem one day. We must take all necessary and possible steps to reduce space waste and remove the debris already there.
Space waste could become a matter of grave concern in the near future. Several companies are planning to launch satellites that will beam an internet connection down to Earth. These aren’t just satellites. They’re a group of satellites called mega-constellations. SpaceX and Amazon propose to launch thousands of satellites to achieve global internet coverage. This means that an additional 50,000 satellites will be in orbit around the Earth. It also means that all the satellites in orbit will have to perform a lot more collision avoidance maneuvers.
In September 2019, the European Space Agency performed the first ever maneuver to avoid colliding with an active satellite. It had to maneuver its satellite to prevent it from hitting a mega constellation. This was the first time an agency had to prevent its satellite from colliding with another active satellite, not a failed or dead one.
It is disturbing to think that pollution caused by humans is not only harming the Earth but is also littering space and might one day interfere with gravitational forces. We must ensure that organizations remove their satellites from orbit in a reasonable amount of time once they reach the end of their mission. The mitigation of space waste is achievable. Space waste is a major problem today, but it doesn’t have to be in the future.
The Earth’s orbit is a fascinating force. We’ve gained so much information about how our planet and the solar system work by keeping satellites in orbit. We can easily communicate with everyone, surf the internet, and much more. We need to use our ability to launch satellites sustainably. We must ensure that future generations will also be able to use the internet, cellphones, and launch satellites too.