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Space junk (debris), an alarming issue in Space by Suchir Godavarthi

Space junk refers to pieces of machinery or debris left in space by humans. It can refer to objects of any size or type and occurs both intentionally and unintentionally, such as dead satellites or remnants of failed missions. A majority of this debris is in low Earth orbit, which is within 2000 kilometers or 1200 miles of Earth’s surface. Space junk has the ability to fall back to the Earth’s surface. The time it takes to fall back depends on the object’s initial altitude. For example, debris below 600 kilometers from the Earth's surface will fall back after orbiting for a few years, while objects over 1000 kilometers from the Earth’s surface can stay in orbit for hundreds of years.




According to the European Space Agency, space debris can include satellites that are dead and/or not in use, satellite fragments, remnants, fragments of early stages of rockets, and dropped tools. Space junk is categorized by size into three groups: below 1 cm, 1 cm to 10 cm, and above 10 cm. There are over 128 million pieces of debris over 1 cm and most are not detectable. Around 900,000 pieces are between 1 to 10 cm, and anything above 10 cm consists of anything from old tools to satellite parts.


Debris in space is a major threat to both manned and unmanned spacecraft. Because the force of an object's impact depends on both its mass and acceleration, even if an object is relatively small, it can still have a significant impact solely due to the speed it is traveling at. This is exactly the case for space junk. Pieces of debris orbit the earth at around 8 kilometers per second, meaning that even small debris can damage spacecraft. For example, the windows of space shuttles were replaced often after collisions with objects smaller than 1 millimeter. Space junk damaging satellites is especially worrying because commerce, communication, travel, and safety systems all depend on functioning satellites. If satellites become significantly damaged, GPS, timing synchronization for finance, banking, and power, and military technologies all get severely impacted. This has serious implications for everyday life.



The United States Department of Def