Following the July-August period when controllers used Tiangong 1's thrusters for strict control of the orbit decay rate, things went quiet and Tiangong 1 settled down to a regime of orbit decay dictated by solar activity. As the solar wind increased and heated up the Earth's atmosphere, decay increased and it then slowed down again as the solar wind reduced.
Early October, small inconsistencies in orbit data coming from SpaceTrack indicated that thruster firings were occurring but this time the effects were consistent with attitude control changes. Thrusters were being used to change Tiangong's orientation but the firings were also making subtle changes to the orbit.
After Shenzhou 9, Tiangong was 'parked' in a 42 degrees .8 inclined, 355 x 366 kilometre orbit. By October 15 it was down to 346 x 353 kilometres. A major two-impulse thuster firing on that day raised it to 367 x 374 kilometres. It was only two kilometres below the highest orbit it had ever achieved back in 2011 November following the post Shenzhou 8 boost.
For a few days thrusters were again used to control the decay but on October 20, it was left to its own devices.
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