When China launched the Yaogan-41 satellite into space late last year, it travelled further than most such objects. Reconnaissance satellites tend to sit in low-Earth orbit (LEO), whizzing around the planet between 11 and 16 times a day (see chart 1). But Yaogan-41 headed for higher ground, some 36,000km from the Earth. There, in geostationary orbit (GEO), the point at which a satellite circles the planet slowly enough to remain above the same point, it began watching.
The Economist
