what are space debris


All the things that people make and put in space are called “space debris.” These objects are mostly made up of pieces of machinery that are no longer working. People also call it space junk.

space junk


There are hundreds of thousands of space debris in orbit. When something is in orbit, it goes around another object. For example, the earth orbits the sun. (Research from NASA)

  • Space debris can vary in size. Some are big while others are small. 
  • Experts estimate that there are millions of space debris that are less than 0.4 inches. Thousands of space debris range between 0.4 inches and 4 inches.
  • The pieces of debris in space float several thousand kilometers above the earth’s surface. Many of these objects can be found in low-Earth orbit (1,250 miles above the surface of the earth).

These objects move all the time because of gravity. A lot of space debris moves quickly. Up to 17,500 miles per hour. Pieces of debris floating in space are a threat to space stations and satellites.

where does space debris come from


Humans are the main source of the space debris problem. It is also possible for space missions to leave things behind in space, either on purpose or by accident. Anything thrown away or no longer used in space is space junk or space debris.  (Research from Iberdrola)

Spent Rocket Bodies

  • Astronauts can only travel to space using rockets. Space rockets have powerful engines that allow them to lift off from the ground and escape the earth’s atmosphere.
  • A special type of fuel powers rockets.  This fuel is called a propellant. The most common fuel in rockets is liquid nitrogen.
  • “Stages” are the large tanks that store the propellant. Each stage carries a specific amount of fuel to propel the rocket.
  • Stages or fuel tanks, separate from the main rocket when they run out of fuel. At high altitudes, old rocket stages may drift away into space, becoming space debris. Also, the stages can explode in space, causing more debris to fall.

Damaged Artificial Satellites

  • An artificial satellite is any object deliberately put in orbit. As of September 2021, there were about 7,500 active satellites in space.
  • Satellites are important parts of the Earth’s communication system.  They send and receive signals from cell phones, computers, and other communication tools.
  • Sometimes, satellites in space can go wrong. There are a lot of different things that can cause this. They are often hit by the debris that already exists in space, or thier systems may fail. 
  • Broken or damaged satellites stay in space, because they are hard to deal with. Satellites outside of Earth’s atmosphere often stay there for hundreds of years as debris in the space around the Earth. These satellites can also smash into other objects, causing them to split into smaller pieces.

Anti-satellite tests

  • Several countries around are adding to the amount of space debris in orbit. 
  • At times the United States of America, Russia, China, and India have intentionally blown up some of their satellites. This was mostly done for testing weapons.
  • Whenever missiles try to hit satellites in low-Earth orbit, the process generates a lot of power. The fragments are sent farther into space, making a field of debris.
  • Because there is no air in space, the debris that comes from explosions can travel at very high speeds. If they hit other things, more debris is made.

Missing Equipment

  • Astronauts carry different pieces of equipment when going on space missions. The tools are for repair and maintenance practices on space stations.
  • During spacewalks, astronauts can easily lose control of the equipment they are using. In November 2008, astronaut Heidemarie Stefanyshyn-Piper accidentally dropped a tool bag during a space mission at the International Space Station (ISS). The bag had several tools, including grease guns, scrapers, and wipes. The toolbag orbited for about 8 months before re-entering the earth’s atmosphere. Upon reentry, it completely burned up.
  • Not all equipment that is lost in space falls back to the planet’s surface. Some may drift farther away from the earth.


There is a good chance some of the space debris in the lower-earth orbit will fall back down to Earth in a few years. Large pieces of debris often don’t burn entirely to ashes and are likely to fall into the ocean.

After a few years, space debris that is in orbit below 375 miles will fall back down to earth. While things in orbit above 600 miles can stay in space for a long time.


Removing space debris is a lot of work. Equipment that can safely remove fragments without hurting the planet must be used in order to do this. (Research from Orbital Debris: A Technical Assessment)

Reusing Rockets

There should be more thought put into reusing rockets. Often, rockets are reusable when they end up back on the earth’s surface in one piece. Reusing rockets will keep space clean because there won’t be as many spent rocket bodies floating around in space. Technology has also made it easier for aerospace companies like Space X to make reusable space rockets.


Deorbiting means taking a satellite out of orbit and pulling it back to the earth’s surface. Basically, satellites that are no longer useful should be taken out of space. When an object from space reaches the earth’s atmosphere, it burns up and is no longer a problem. However, only small debris can completely burn up, so bigger objects need a different method.


Scientists are now working on making satellites that self-destruct when they are about to stop working. As the satellite approaches the end of its useful life, it will move towards the earth’s atmosphere. Then it will burn up instead of becoming space debris.  The satellite’s onboard computer system will make sure it re-enters the atmosphere someplace it won’t cause harm. 

Reducing Orbital Lifetime of Space Objects

Orbital lifetime is the amount of time an object in orbit spends in the space around the Earth. There are ways to speed up the natural decay process of a space object so that less debris is left in space. As a result, space debris won’t build up in a single place.


Space pollution is becoming more and more of a problem. Humans throw objects of all sizes and shapes into space, which makes debris fields. Most of the debris in space is caused by space missions. Communication satellites and space stations are at risk of being hit by debris, which causes major damage.

Collisions in space do a lot of damage to space stations because debris moves so quickly. With time, space will be full of so much debris that it will make it difficult for people to go into space and explore.

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