How many Earth observation satellites are in space in 2018?

Satellites orbiting the Earth

Artist’s rendition of satellites orbiting the Earth – rottenman/123RF Stock Photo

Earth Observation (EO) satellites currently account for over one third of the operational satellites orbiting the Earth. As we described two weeks ago, according to the Union of Concerned Scientists (UCS) satellite database there were 1 980 operational satellites at the end of April 2018, and 684 of these have a main purpose of either EO or Earth Science.

This represents an increase of 10% compared to April 2017. However, the real story is the growth in this market over the last few years. In January 2014 there were only 192 active EO satellites according to HCS, which means it has grown by 250% in just four years – a phenomenal growth in reality and a good indication we’re in a growing industry.

What’s behind this growth in EO satellites?
The vast majority of this increase is down to the development, and launch, of cubesats mostly by the USA companies Planet and to a lesser extent Spire. Planet themselves have launched almost 300 cubesats since 2013, and according to the UCS database there are around 190 still active.

The Planet cubesats, and those from Spire and others, are often launched in large groups; Planet themselves launched 87 in one go in February 2017. Whilst these are significant group launches the satellites themselves are each recorded individually, by both the UCS and the United Nations Office for Outer Space Affairs (UNOOSA), resulting in the growth in numbers.

Whilst there are still a significant number of cubesats being launched – 20 active EO cubesats have been put into space in 2018 – the overall growth has slowed. Last year, Planet achieved their aim of being able to image the globe’s entire landmass every day and so this year they’ve only launched five to date.

Obviously, cubesats have shorter operational lifespans than larger satellites, and there will need to be continual launches in the coming years to maintain the current fleets. It will be interesting to see where the next big EO satellite growth spurt will come from!

Size of Earth observation satellites
Cubesats are generally considered satellites who have a launch mass below 10 kg; with microsats having a launch mass between 10 and 100 kg; small satellites are between 100 and 500 kg; and larger satellites are those with a launch mass of over 500 kg. Of the current active EO satellites:

  • 267 are cubesats accounting for 39.04% of the total
  • 66 are micro satellites representing 9.65%
  • 82 are small satellites representing 11.99%
  • 204 are large satellites representing 29.82%
  • The remaining 9.5%, 65 satellites, have no size listed – these are mainly military satellites from China and USA.

What do Earth observation satellites do?
Whilst the 684 satellites we are looking at today have a purpose of EO or Earth Science, there are further details on their specific roles. So we have:

  • Optical Imaging: 338 satellites.
  • Radar imaging: 49 satellites.
  • Infrared imaging: 8 satellites.
  • Hyperspectral/Multispectral imaging: 10 satellites.
  • Meteorology: 82 satellites.
  • Earth Science: 62 satellites.
  • Electronic intelligence: 64 satellites.
  • Video: 2 satellites.
  • Other purposes: 12 satellites.
  • 57 satellites simply list EO as their purpose.

Although, it should be noted that some of the satellites have more than one role.

Who uses the Earth observation satellites?
The users for the EO satellites listed by the UCS are:

  • 00% of users are commercial users
  • 97% of users are government users.
  • 49% of users are military users.
  • 50% of users are civil users.

Again, it should be noted that some of these satellites have multiple users.

Who controls Earth observation satellites?
Unsurprisingly, given that Planet and Spire are USA companies, the USA controls 50.15% of the active EO satellites. They are followed by China who control 17.84%, and then Japan, Russia and India who each control just over 3% of the EO satellites.

In total, there are 43 different countries listed as having control over EO satellites, which is a slight increase from last year.  It should be noted that there are satellites run by multinational agencies such as the European Space Agency (ESA).

What’s next?
We’re not currently expecting a huge increasing in the number of active EO satellites in the short term. However, the potential offered by video could soon see new constellations being launched.

Equally, there will still be a lot of interesting EO satellites launched. We had ESA’s Aeolus last month, and in the next ten days we’ve got planned launches for the UK’s NovaSAR-S and SSTL-S1 satellites and NASA’s ICESat-2.

It’s clear that the amount of EO data available is going to continue growing, it’s up to all of us to put it to good use!

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