Remote sensing

More and more and more

I read in the editorial column of LiDAR  News (May 2015, Vol 5, no. 4) that one of the keynote speakers at ASPRS IGTF 2015 “highlighted the fact that in 2014, 4,500 earth imaging satellites were announced by 72 countries”. That’s a lot of satellites. And they are only the Earth observing ones.

Granted that not all of those will get launched, and some (I assume) will be for applications that mean their operational life-span is relatively short-lived, but that still leaves a lot of new objects making their way into orbit. To put the number in context, it is estimated that 6,600 satellites have been launched since the space age began [https://en.m.wikipedia.org/wiki/Satellite].

There are currently about 1,100 active satellites in orbit, including both government and commercial, Earth observation platforms and other types such as communications. On top of that there are almost 3,000 broken satellites slowly retrograding to be burnt up in the atmosphere [http://talkingpointsmemo.com/idealab/satellites-earth-orbit]. Roughly another 16,000 pieces of debris larger than 5 cm and over 300,000 items larger than 1 cm  [https://en.wikipedia.org/wiki/Space_debris] are also in orbit as ‘space junk’. These numbers are indicative and come from a quick web search, but they give an idea of the number of hazards that we have put into orbit.

As someone who’s livelihood is made through the analysis of images captured by such systems, you may think that I should welcome the launch of another 4,500 satellites. More data, more opportunities. Mainly I do welcome this, because I know that the launches will be made over a relatively drawn-out time period and into different orbital patterns. But the issue of space debris does concern me – so many services rely on the reliable operation of satellites (whether for observation or other uses) and so much of modern society is dictated by satellite services. Satellites have already collided with each other [https://en.wikipedia.org/wiki/2009_satellite_collision], and with increasing amounts of debris in orbit it is more likely that satellites will be affected or destroyed in future. Indeed, the issue of space debris has even been picked up by the BBC in recent weeks [http://www.bbc.co.uk/news/science-environment-33782943].

It all comes back to that old adage, just because we can (launch more), does that mean we should?

Debris-GEO1280