Issue 85

China: Yaogan-40-01 Now in Formation

13 Nov: China increased the altitude of Yaogan-40C to match that of Yaogan-40A and 40B. The three satellites are now in formation and likely performing their radio collection and geolocation mission . China launched all three satellites on 10 September and shortly afterward increased the altitude of 40A and 40B while…

13 Nov: China increased the altitude of Yaogan-40C to match that of Yaogan-40A and 40B. The three satellites are now in formation and likely performing their radio collection and geolocation mission. China launched all three satellites on 10 September and shortly afterward increased the altitude of 40A and 40B while decreasing the altitude of 40C. As noted by Robert Christy, this maneuver pattern is similar to the deployment of the Yaogan-31 satellites. – The effect of having satellites orbit at two slightly different orbit heights is that the two orbit planes move at different rates with the lower orbit moving faster. By the time the three satellites come together, the orbit of the singleton will have moved to the east of the pair at the higher altitude. -While the results of the maneuver were similar, there were some differences between the YG-31 and YG-40 deployments. It appears China is continuing to try slightly different deployment techniques.
  • For YG-40-01 only one satellite maneuvered to create the formation. The singleton, YG-40-01C, increased its altitude to match YG-40A & B. In the case of YG-31D/E/F, all three satellites maneuvered, the pair lowered their altitude initially and then increased their altitude. The singleton also decreased its orbit to match the pair.
  • YG-40 spent 60 days to complete its maneuvers and begin operating in formation. YG-31 took about half that time.
  • YG-40 is operating in a new orbit (852km altitude and 86° inclination) for Chinese ISR satellites. YG-31 satellites orbit at ~1,090km and 65°.
– China’s use of the Yaogan-40-01 designation is a possible indicator of more missions in the future. Total size and timeline for developing this constellation are unknown. Yaogan-31 consists of 12 satellites (operating in 4 groups of 3 satellites).

Yaogan-40A, Yaogan-40B and Yaogan-40C formation

Yaogan-40A/B/C compared with the Yaogan-31K/L/M orbital plane

Yaogan-40 Group 1 altitude maneuver history, 13 Sep-12 Nov 2023

Yaogan-31 Group 2 deployment maneuver history