Einstein's theory of relativity predicts that time on the Earth's surface flows differently than on a higher orbit - the planet's gravity is weaker there. And the GPS satellites account for this difference!

On their high geostationary orbits time overtakes "our" time by as much as 38 millionths of a second per day. And the GPS needs 50 billionths of a second accuracy to work properly.

If the system didn't consider the theory of relativity, the GPS would "go away" by 10 kilometers per day and would be completely useless.

Shortly after Shiyan-12-01 and Shiyan-12-02 entered their target orbit, satellite spotters turned their attention to the maneuver performed by the U.S. USA 270.

It was launched in 2016 and is also an inspection satellite. USA was directed to intercept the Shiyan.

For a while, USA-270 approached a pair of Chinese satellites. Afterwards, they performed a counter maneuver, diverging in different directions.