Image courtesy of ESA
Note: The debris field shown in the image is an artist’s impression based on actual data. However, the debris objects are shown at an exaggerated size to make them visible at the scale shown

This is our update on the satellites currently orbiting the Earth at the start of 2019.

How many satellites are orbiting the Earth?
According to the Index of Objects Launched into Outer Space, maintained by the United Nations Office for Outer Space Affairs (UNOOSA), there were 4 987 satellites orbiting the planet at the start of the year; an increase of 2.68% compared to end of April 2018.

UNOOSA recorded 382 objects launched into space during 2018, which is 15.67% lower than the 453 objects launched in 2017 that was the record year for objects launched into space. Part of this reduction is down to the fact that Planet, who have been regular cubesat launchers over the last few years have achieved their initial goal of imaging the Earth’s landmasses every day, and so they are currently focussed on maintaining, rather than expanding their constellations.

According to UNOOSA, in history a total of 8 378 objects have been launched into space. Currently, 4 994 are still in orbit – although 7 of them are in orbit around celestial bodies other than the Earth; meaning there are 4 987 satellites whizzing around above our heads every single day.

The growth of objects in space
The table below shows the number of objects launched into space in every year since the first launch in 1957. For the first eight years there is steady growth and then from 1965 to the start of 1990 generally around one hundred fifty (± twenty) objects being launched each year. The next twenty years were a bit up and down with a low of 72 in 2005, however the cubesat driven growth can be seen starting in 2013.

Year	No	Year	No	Year	No	Year	No	Year	No	Year	No
1957	2
1958	8
1959	14
1960	20	1970	130	1980	129	1990	168	2000	121	2010	120
1961	38	1971	156	1981	158	1991	135	2001	87	2011	129
1962	77	1972	133	1982	145	1992	130	2002	97	2012	134
1963	72	1973	138	1983	154	1993	108	2003	88	2013	210
1964	107	1974	128	1984	163	1994	123	2004	74	2014	242
1965	163	1975	156	1985	165	1995	105	2005	72	2015	223
1966	145	1976	158	1986	134	1996	100	2006	96	2016	221
1967	159	1977	137	1987	135	1997	152	2007	111	2017	453
1968	140	1978	165	1988	145	1998	157	2008	109	2018	382
1969	138	1979	124	1989	139	1999	129	2009	125

The next ten years will interesting, it is unlikely that the same level of recent growth will be maintained, but equally there will still be a significant number of satellites being launched each year. The UK Government last summer forecast that there will 2 000 small satellites launches by 2030.

Where have all these objects in space been launched from?
There are 31 different launch facilities listed by UNOOSA as having put objects into space including a number of air-based, sea-based and even submarine based launches. The most used sites in history are:

·         Plesetsk Cosmodrome in Russia with 2 101 launches

·         Baikonur Cosmodrome in Kazakhstan with 1 734 launches.

·         Cape Canaveral in the United States with 1 203 launches.

·         Vandenberg Air Force Base in the United States with 1 103 launches.

·         Centre Spatial Guyanais in French Guiana with 510 launches.

How many of these orbiting satellites are working?
The Union of Concerned Scientists (UCS) keeps a record of the operational satellites and their latest update provides details to the end of November 2018. Using this database together with the UNOOSA Index shows that there are currently 1 957 active satellites in orbit, which represents just under 40% of the satellites orbiting the planet. Interestingly, this is also 1.16% lower than the last update of this database for April 2018.   In effect, this means that we there are 3 030 limps of metal flying around the Earth at thousands of miles per hour doing absolutely nothing.

It should be noted that the United Nations have 72 satellites listed as having launched in December 2018 after the UCS database was last updated. However, for the rest of this section, we’ll use the UCS figures for consistency,

What are all these satellites doing? 
Using the UCS update, as at the end of November, the main purposes for the operational satellites are:

·         Communications: 777 satellites.

·         Earth observation: 710 satellites.

·         Technology development/demonstration: 223 satellites.

·         Navigation/Positioning: 137 satellites.

·         Space science/observation: 85 satellites.

·         Earth science: 25 satellites.

Although, it should be noted that some of the satellites have multiple purposes.

Who uses the satellites directly?
The four categories of users in the previous section shows that:

·         848 satellites are listed as having commercial users

·         540 with government users

·         422 with military users; and

·         147 with civil users.

It should be noted that 279 satellites (14.25%) are listed as having multiple uses.