Sail to remove space junk
The European Space Agency has removed a satellite by means of a drag sail. In the longer term the sail might remedy ongoing problems with space junk.
On 4 October 1957, the Soviet Union became the first nation to put a satellite, Sputnik, into an orbit around Earth. Today, 65 years later, there are around 3000 active satellites among 8000+ human-made objects in orbits. But there are plans for tens of thousands more satellite launches.
The quantity of redundant space junk orbiting Earth is becoming so problematic that the European Space Agency, ESA, has chosen to do something about it, successfully testing a prototype of a new technology which could help remove space junk on a large scale.
The ESA has developed a sail that can drag satellites and other objects out of orbit and direct them down towards Earth’s atmosphere – a process known as deorbitation.
The technology is called the Drag Augmentation Deorbiting System (ADEO), and the prototype uses a customised nylon sail – an aluminiumcoated polyamide sail membrane some 3.6 square metres in area.
The test sail was folded into a pack just 10 x 10 x 10cm that was subsequently mounted on a used CubeSat – a small satellite. The CubeSat was launched into orbit in late December 2022 from the ION Satellite Carrier platform.
Shortly afterwards the ADEO sail was unfolded to successfully drag the small CubeSat towards Earth’s atmosphere in a process which will take 1 year and 3 months instead of the 4-5 years it would take the satellite to make the journey on its own.
The sail increases the atmospheric surface resistance effect, dragging a satellite faster out of its fixed orbit. When the satellite enters Earth's atmosphere, it will burn up, which is an easy way to get rid of small pieces of space junk.
The ADEO test sail is customised to drag small satellites of 1kg to 100kg out of orbit. Known as “Show Me Your Wings”, the test sail mission was the last qualification test to be made before the ADEO sail can be produced on a larger scale. The longer term aim is that ADEO sails will remove all European satellites once their missions have been completed.
The existing test sail is the smallest ADEO model, while for the biggest satellites a sail with an area of 100m2 is proposed. It takes 0.8 seconds for the smallest sail to unfold, but the biggest sail requires up to 45 minutes.
Other nations are also testing drag sails to reduce space junk. Last year China tested a 25m2 sail to help rotate a piece of space machinery.