Space junk derives from various sources, such as used satellites, spent booster rockets, and parts of shattered spacecraft. This junk lingers above our atmosphere, until it collides with something else.
According to Laboratory Roots, a key concern is when space junk collides with objects to create smaller pieces of space debris. While spacecraft can avoid larger items of such debris, smaller items pose a risk.
The key risk that smaller bits of space debris pose is related to the orbital velocity – the faster an item moves, the bigger its impact. Consequently, a small item moving at tens of thousands of miles per hour can cause substantial damage when it hits another object.
In a move to protect astronauts onboard the International Space Station, whipple shields have been put in place (a type of hypervelocity impact shield ). These shields function to mitigate impact energy from items of space debris that make contact with a space ship or with the space station.
A real risk also exists that space junk could accumulate to such a level that it becomes almost impossible to safely navigate a spacecraft through all the mounting debris.
Different ideas have been put forwards to try to clean up the orbit around the Earth. Suggestions being tested out by NASA include the application of large nets to try to capture space junk or using robotic ‘grabber’ arms to haul away larger items.
Another idea, from the European Space Agency, is to use magnetic space tugs. With this concept, a magnetic field would be produced so that it works a little like a tractor beam. The beam would be used to push away objects, so that the space junk is moved out of orbit. This technology would require a special piece of equipment termed a magnetorquer, a type of powerful electromagnet.
Back in 2017, Japan attempted to develop this type of technology, producing an electromagnetic tether, which was approximately 6 football fields in length. However, the operation of the device was not successful.
Many of the ideas continue to be tested out by scientists. In the meantime, the space junk problem – an issue of humanity’s own making – continues to cause risks to our use of space.
