How many satellites are orbiting the Earth

A satellite can be defined as an artificial body placed in orbit around a planet in order to collect information, or for communication. TheUnited Nations Office for Outer Space Affairs(UNOOSA) monitors, and maintains a searchable database of, objects launched into space. According to UNOOSA, at the end of August 2015, there were 4 077 satellites orbiting the Earth, which equates to 56.63% of all satellites ever launched.

Of the satellites no longer in orbit, 1 329 have been recovered, 1 539 decayed and 175 deorbited; and interestingly given the definition above, 47 are on the Moon, 15 on Venus, 13 on Mars and 1 on the asteroid EROS. Last year also saw more launches than any other year in history with 239, by the end of August this year we’d only had 106 launches.

The Union of Concerned Scientists (UCS) details the currently active satellites through their database, and they note that at the end of August 2015, of the 4,077 satellites in orbit only 1,305 are active. This means there is currently 2 772 pieces of junk metal circling above your head!

So what are the thirteen hundred active satellites actually doing? According to the UCS over 50% of these satellites have a purpose described as communications. The secondary biggest purpose is Earth observation with 26% of active satellites, 333 in total, and we’ll look at these in more detail next week. The next largest category is technology demonstration with 141 satellites, followed by navigation with 91 satellites and finally the remaining 5% of satellites have a purpose described as space science.

Commercial users account for 52% of the satellites, followed by Governments with 30%, 27% have military users and 8% are civilian users. The percentages total more than one hundred percent as some satellites have for multiple purposes. The civil users are mostly Universities or other academic institutes that have launched their own satellites.

The USA is biggest operator of active satellites with over 500, followed by China and then Russia. The UK is listed as the operator on only 40 satellites, although we also have a share in the 26 European Space Agency (ESA) ones.

An interesting point is the most popular launch sites for satellites. The Plesetsk Cosmodrome in Russia has launched the most satellites in history, over 2,000. This is followed by Baikonur Cosmodrome in Kazakhstan with 1,500, with this site being famous for launching both Sputnik 1 and Yuri Gagarin’s first manned space flight in Vostock 1. After this are the American sites of Cape Canaveral, Florida and the Vandenberg Air Force Base in Lompoc, California, followed by the ESA launch site of French Guiana.

The UK currently doesn’t feature anywhere on the list, but the first steps to changing this are underway. The UK Government is planning to have a spaceport established in this country by 2018; with three sites in Scotland short-listed together with Newquay in Cornwall, which is an exciting prospect for Pixalytics as we are both based in south-west. The initial focus is likely to be sub-orbital flights, but who knows what could be launched in time.

When you next look up into the sky, remember that there are over four thousand hunks of metal shooting around the Earth at speeds of many thousands of the kilometres an hour high above the clouds!