Space Junk – a serious threat to our space missions

In 2009, a Russian and an American satellite in orbit collided with each other creating lots of debris in the process. In recent years, space junk has increased significantly, endangering future space missions. Space junk or space debris is defined as machinery or debris left by humans in space. These could range from dead satellites to small paint flakes from a rocket left over in orbit. Scientists use ‘Go Pro’ cameras fitted inside rockets to study the amount of debris created during each rocket and satellite launch. While the paint flakes and debris may seem quite small, the damage they can cause to orbiting satellites is monumental. This is because space junk doesn’t sit in space motionless. They orbit the Earth at speeds reaching around 25,000 kmph which can make a small debris pierce a satellite like a bullet. These orbiting satellites today control a lot of our daily life from traffic alerts, Google Maps and telecommunication. 

The Hubble telescope. Image courtesy of NASA via Unsplash.

The Hubble Telescope, launched in 1990, has recently been succeeded by the James Webb Telescope in 2022. While still operational, Hubble has been repaired and adjusted multiple times to keep it functioning for the sake of science. Unlike James Webb which orbits at Lagrange point (L2), Hubble orbits the Earth in the ‘Low Earth Orbit’ region. This region of space is full of space debris and junk which has damaged the telescope on multiple occasions. ‘Low Earth’ orbit is defined as the region of space about 160-1000 km above the surface where satellites and certain space telescopes orbit. For comparison purposes, most planes fly at 35,000-40,000 feet which is about 14 km above the Earth’s surface!

Artistic impression of space debris surrounding Earth. Image courtesy of National Geographic.

Today with around 2000 satellites still active, we have amassed around 35,000 pieces of space junk. But note these numbers just include objects over 10 cm in size. There are many more debris pieces so small they go undetected until they cause some damage. The International Space Station (ISS), that houses around 6 astronauts at any given time, orbits the Earth in low Earth orbit. According to data collected by NASA, ISS has had to perform 25 debris avoidance manoeuvres since 1999. 

Clearing up this mess has become a global priority to prevent the Kessler Syndrome, a hypothetical scenario where the low Earth orbit becomes useless due to the amount of space junk and debris. It describes a scenario when the region of space reaches a point where space debris almost resembles a cloud of dust destroying satellites and rockets they pass by. This is particularly dangerous because that means the ISS will be under serious threat of breakage and other satellites that power your Maps could stop working too. To prevent this from becoming reality, there have been a couple of ideas created to curb this issue. One such idea, developed and tested by Airbus engineers, is to attach a harpoon to a satellite and drag the debris to the atmosphere so it can burn upon re-entry. Another idea was recently developed by a Japanese start up called Astroscale. Their idea is using a magnetic system on a satellite to attract metallic debris and burn it up in the Earth’s atmosphere. With companies like SpaceX making satellite launches cheaper and reusable, scientists are concerned that the space junk problem will just get worse. Governments today are setting up some common space laws to be enforced with regards to this growing issue.  

Astroscale satellite. Image courtesy of Astroscale Holdings Inc.

Today the rate of launches is still more than the rate of junk clean-up according to Moriba Jah, an expert at UT Austin on orbital debris. Luckily, the recent years have proven that if enough awareness is raised about this issue, it can be controlled.

Ananya Ganapathy (she/her) is a second year Astrophysics student.


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