In October 1957, the first artificial satellite, Sputnik 1, was launched into space. Today, 60 years later, the space surrounding Earth is crowded: communication systems, Earth monitoring, space observation equipment… the world we know totally depends on satellites acquiring and relaying us a huge quantity of information every day.
More than 5,250 launches have resulted in some 42,000 tracked objects in orbit, with a total mass accounting for more than 7,500 tonnes. Only about 1,200 of them are intact operational satellites; the remaining includes defunct satellites, spent rocket boosters or fragments generated mainly by explosions of spacecraft and sometimes collisions also called “space junk”.
With 30 or more small satellites released with each launch, and a more actual rate of 70-90 launches a year, the amount of injected objects into orbit is rising, drastically increasing the probability of collisions. As debris travels at speeds up to 28,000 km/h, even small debris can cause a great deal of damage when colliding with satellites, spacecraft, or other space junk which often generates even more pieces of debris.
That’s the reason why US Space Surveillance Network tightly monitor and track objects above 5cm in size, in low-Earth orbit LEO – altitudes below 2,000 km, and at geostationary altitudes GEO – altitude approaching 36 km.
It is worth noting that LEO regions host most of the satellites we launch, as well as the International Space Station and the Hubble Space Telescope. Without taking any action, some orbit regions like the LEO may experience a collisional cascading process rending them too dangerous for space activity within two decades. Mitigating space debris generation is therefore crucial to carry on our space activities.
The first space cleaning mission named RemoveDebris has just been launched as of April 2nd 2018. This 100kg satellite will test the efficiency of nets and harpoons to capture objects in orbit and send them back into Earth’s atmosphere to burn up, by deorbiting them.
This project, undertaken by the University of Surrey UK, is co-funded by the European Commission FP7 research project and the consortium partners, including Airbus. If this mission is successful, we hope the launch of more cleaning satellites will follow in the near future.
Marie, Consultant, Leyton France
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