This is our annual update on the satellites currently orbiting the Earth.
How many satellites are orbiting the Earth?
According to the Index of Objects Launched into Outer Space maintained by United Nations Office for Outer Space Affairs (UNOOSA), there are currently 4 256 satellites currently orbiting the planet, an increase of 4.39% compared to this time last year.
221 satellites were launched in 2015, the second highest number in a single year, although it is below the record of 240 launched in 2014. 2016 may fall slightly short, as to date only 126 launches have occurred this year. The increase in satellites orbiting the Earth is less than the number launched last year, because satellites only have limited lifespans. The large communication satellites have expected lifetimes of 15 years and more, whereas the small satellites, such as CubeSatâ€™s, may only have expected lifespans of 3 â€“ 6 months.
How many of these orbiting satellites are working?
The Union of Concerned Scientists (UCS) details which of those orbiting satellites are operational and it is not as many as you think! According to their June 2016 update, there are currently only 1 419 operational satellites â€“ only about one third of the number in orbit. This means there is quite a lot of useless metal hurtling around the planet! This is why there is a lot of interest from companies looking at how they capture and reclaim space debris, with methods such as space nets, slingshots or solar sails proposed.
What are all these satellites doing?
According the UCS data the main purposes for the operational satellites are:
- Communications with 713 satellites
- Earth observation/science with 374 satellites
- Technology Demonstration/Development with 160 satellites
- Navigation & Global Position with 105 satellites; and
- Space Science with 67 satellites
It should be noted that some satellites do have multiple purposes. We will discuss the operational Earth observation satellites in more detail next week.
Who uses the satellite directly?
Itâ€™s interesting to note that there are four main types of users listed in the UCS database, although 17% of the satellites have multiple users we are concentrating on the main user:
- 94 satellites listed with civil users: These tend to be educational institutes, although there are other national organisations also included. 46% of these satellites have a purpose of technology development, whilst Earth/Space science and observation account for another 43%.
- 579 with commercial users: Commercial organisations and state organisations who want to sell the data they collect. 84% of these satellites focus on communications and global positioning services; of the remaining 12% are Earth observation satellites.
- 401 with Government users: Mainly national Space organisations, together with other national and international bodies. 40% of these are communications and global positioning satellites; another 38% focus on Earth observation. Of the remainder space science and technology development have 12% and 10% respectively.
- 345 with military users: Again communications, Earth observation and global positioning systems are the strong focus here with 89% of the satellites having one of these three purposes.
Which countries have launched satellites?
According to UNOOSA around 65 countries have launched satellites, although on the UCS database there are only 57 countries listed with operational satellites, again some satellites are listed with joint/multinational operators. The largest are:
- USA with 576 satellites
- China with 181 satellites
- Russia with 140 satellites
The UK is listed as having 41 satellites, plus weâ€™re involved in an additional 36 satellites that the European Space Agency has.
Remember when you look up!
Next time you out at look up at the night sky, remember that there is over two million kilograms of metal circling the Earth between you and the stars!