Keeping Space Clean
The space junk being referred to here is any piece of machinery or debris left by humans in space. This includes large objects like dead/failed satellites that have been left in orbit at the end of their mission and smaller items like bits of debris or paint flecks that have fallen off of a rocket. Sometimes space debris can be created by intentional collisions or blowing up of satellites (which several countries including the USA, China, and India have done in the past). “The biggest contributor to the current space debris problem is explosions in orbit, caused by left-over energy – fuel and batteries – onboard spacecraft and rockets. Despite measures being in place for years to prevent this, we see no decline in the number of such events. Trends towards end-of-mission disposal are improving, but at a slow pace,” explains Holger Krag, Head of the Space Safety Programme. Statistics-wise, there are around 3,000 pieces of space junk that are larger than 10 centimeters and 128 million pieces of space junk larger than a millimeter compared to the 2,000 active satellites currently orbiting Earth. Space junk is the result of humans launching objects from Earth. The debris then stays there until it re-enters the atmosphere. Some objects in the lower orbits, around a few hundred kilometers from Earth, can return within a few years and burn upon re-entry for the most part so they don’t reach the ground. Although, large debris like satellites at higher altitudes like 36,000 kilometers, which is where communication and weather satellites are usually located, can orbit Earth for hundreds or even thousands of years.
While space junk doesn’t seem too dangerous to space exploration, it can be quite dangerous to the other satellites in Earth’s orbit. Satellites have to purposefully move out of the way so they are not damaged or destroyed. Fortunately, collisions are rare. Still, hundreds of collision avoidance maneuvers are performed per year. This includes the International Space Station, or ISS. In order to reduce the amount of space debris being created, the UN asks their companies to remove their satellites from orbit within 25 years after their mission ends. Unfortunately, this is difficult to enforce since satellites often fail. On the bright side, numerous companies worldwide have brainstormed solutions to this problem. The ESA is actively working to support the guidelines for the long-term sustainability of outer space activities from the UN Committee on the Peaceful Uses of Outer Space. Some methods include funding the world’s first mission to remove a piece of debris from orbit, helping to create an international space sustainability rating, and developing technologies to automate collision avoidance and reduce the impact on our environment from space missions. An additional method that companies use to clean up Earth’s orbit is to drag the dead satellites from orbit back into the atmosphere where they will burn up by using different tools including harpoons, large nets, magnets, and lasers. Many companies have already taken initiative and began researching and funding, while others have already planned missions and trials that could launch as soon as 2023 to clean up space junk.
Bibliography
Clark, Stephen. “Privately-Funded Mission Takes off to Begin Space Debris Cleanup Trials.” Spaceflight Now, 22 Mar. 2021, spaceflightnow.com/2021/03/22/privately-funded-mission-takes-off-to-begin-space-debris-cleanup-trials/.
“What Is Space Junk and Why Is It a Problem?” Natural History Museum, www.nhm.ac.uk/discover/what-is-space-junk-and-why-is-it-a-problem.html.
https://scx2.b-cdn.net/gfx/news/hires/2018/whyspacedebr.jpg
https://news.mit.edu/sites/default/files/styles/news_article__image_gallery/public/images/201706/MIT-Orbit-Debris_0.jpg?itok=is7Mk60S
