Plastics in the ocean has become an issue of global concern - but there's an equally pressing issue of pollution in Space.
Since humanity first started blasting objects into space there has been a slow build up of trash in low earth orbit.
No one knows exactly how much space junk is orbiting the earth, but there could be millions of tiny bits of debris orbiting the earth at a speeds of up to 17,000 miles per hour.
The more debris, the harder it is to launch space missions without risk of collision. There are also fears that some of this debris could pose a safety risk to the International Space Station (ISS).
In fact that was the plot of the 2013 movie Gravity.
So, how do you remove the amount of junk that is in the atmosphere?
Well the European Space Agency has developed one such project in association with Stevenage-based Airbus Space and Defence and the Surrey Space Centre (SSC) at the University of Surrey.
It plans to use a space harpoon to help remove the debris - it would work like this:
The spacecraft features three technologies to perform what is known as Active Debris Removal (ADR):
Firstly a net and a harpoon to capture debris, secondly a Vision Based Navigation (VBN) system to develop rendezvous techniques in orbit with space debris and includes a drag sail to speed up deorbiting of the whole mission.
Watch the ESA's documentary on space debris below
The mission timelines will see the net deployed in October this year, followed by the VBN in late December and then the Stevenage-designed harpoon in February 2019.
The experiments will all be carried out below the orbit of the ISS.
The net experiment, developed by Airbus in Bremen, will see a cubesat (pictured above) sent into space. When the cubesat is 5 metres away, it will then be targeted by the net and captured at approximately 7 metres before it floats away .
The VBN system from Airbus in Toulouse will test 2D cameras and a 3D LIDAR (light detection and ranging) technology to track a second cubesat deployed from the main spacecraft. The VBN system will track its rotation and movement away from the main spacecraft. At the same time the cubesat will transmit its true position to the main spacecraft, enabling the performance of the VBN to be measured. This cubesat will then float and deorbit naturally.
The Airbus Stevenage designed harpoon will see a 1.5 metre boom deployed from the main spacecraft with a piece of composite panel on the end. The harpoon will be fired at 20 metres/sec to penetrate the target and demonstrate the ability of a harpoon to capture debris.
After completion of the Airbus designed ADR, the main spacecraft will deploy the drag sail developed by SSC which will de-orbit the craft in approximately 8 weeks. Without the drag sail, de-orbiting would take more than 2.5 years.