How Many Earth Observation Satellites in Orbit in 2015?

Artist's rendition of a satellite - mechanik/123RF Stock Photo

Artist’s rendition of a satellite – mechanik/123RF Stock Photo

If you’d like the update for 2016, please click here.

Following last week’s blog on the number of satellites orbiting the Earth, this week we’re focussing on Earth observation (EO) satellites. According to the Union of Concerned Scientists database, there were 333 active EO satellites on the 31st August 2015.

Examining these numbers further, reveals almost half have a purpose defined as providing optical imaging, with meteorological satellites account for another 13% and 10% providing radar imaging. There is also a small group with the generic purpose of Earth Science; however, more interestingly is the category of Electric Intelligence. Over 20% of EO satellites have this category, and these satellites have exclusively Military users; there are four countries with these satellites, the USA has the most followed by China, then Russia and France. Who knows what exactly they do?

Of the 333 active EO satellites, 290 are in low earth orbits, 34 in geostationary orbits and 9 are in an elliptical orbit. The oldest EO satellite still operational is the Satélite de Coleta de Dados (SCD) 1 which was launched in 1993; it’s a Brazilian satellite providing environmental data. Unsurprisingly, over half the active EO satellites were launched in the last five years, although this does include Planet Lab’s twenty-eight strong Flock-1 constellation launched in 2014 and 2015, they provide imagery with a spatial resolution between 3 and 5 m.

Picking up on the launch sites we looked at last week. The most popular launch site for EO satellites is the Vandenberg Air Force Base in Lompoc, California, followed by the two Chinese sites of Taiyuan Launch Centre and Jiuquan Satellite Launch Centre. The top five is completed with the Baikonur Cosmodrome in Kazakhstan, and Cape Canaveral in Florida; although it is worth noting that 22 of Flock-1 constellation were launched from the International Space Station.

In terms of numerical supremacy, the USA controls 34% of all EO satellites, China is next with 21% and then Japan with 6.3%. The UK is listed as controlling only 1 satellite, DMCii’s wide imaging DMC-2 satellite; although, we’ve also participated in 8 of the listed European Space Agency (ESA) EO satellites.

In terms of the future, we’re expecting both Jason-3 and Sentinel-3A to be launched later this year. 2016 could see a variety of launches including ESA’s Sentinel-1B and 2B, cloud, aerosol and radiation mission Earthcare and the ADM-Aeolus Wind satellite; DigitalGlobe’s commercial Worldview 4 satellite that will have a panchromatic resolution of 30 cm and multispectral resolution of 1.20 m; and Japan’s Advanced Land Observing Satellite, ALOS-3.

As we often say, it’s an exciting time to be part of Earth observation! Why not get involved?

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