The most obvious answer is that they don’t want to deorbit the station shortly, but why?
Some calculations with the TLEs and SGP4 show the following Tiangong-2 / ISS close encounters:

2018-07-13 09:11:01.384   Dmin= 25.93 km, Vrel= 6.02 km/s
2018-07-30 15:34:39.470   Dmin= 23.16 km, Vrel= 7.30 km/s
2018-08-16 08:06:30.046   Dmin= 31.63 km, Vrel= 8.46 km/s

Since the TLEs age is just a few hours, a reasonable accuracy on Dmin should be better than +/- 2 km.
Does the Tingong-2 have some optical/radar capabilities to observe the ISS?
I’m asking because I’m trying to understand whether the Chinese might be interested in close encounters with the ISS.

  • 1
    $\begingroup$ Interesting question! Hmm... let's see, have there ever been other cases of the Chinese government or military spying in the news? Also, slightly related: Is 45 km unusually close to pass the ISS and deploy a microsatellite without warning? $\endgroup$
    – uhoh
    Aug 20, 2018 at 0:30
  • 2
    $\begingroup$ Also slightly related: ISS - Tiangong 2 minimum safe distance. $\endgroup$
    – Cristiano
    Aug 20, 2018 at 10:25
  • 1
    $\begingroup$ Not sure about the title... if it's in an orbit similar to ISS, then it's definitely not 'so high'; 400km of ISS is a rather low orbit with a significant atmospheric drag. $\endgroup$
    – SF.
    Aug 20, 2018 at 12:16
  • 1
    $\begingroup$ I'm referring to the fact that after the big deboost of about 88 km, they did an even bigger reboost (97 km). Would you suggest a better title? $\endgroup$
    – Cristiano
    Aug 20, 2018 at 12:46


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.