Issue 96

Issue 96

China: VLEO Testing?

29 Apr: China appears to be conducting some coordinated testing in VLEO with its Shiyan-25 (SY-25) and QianKun-1 (QK-1) satellites. Both were launched within a month of one another and are operating in the same orbital plane with nearly identical RAAN and inclination. SY-25's orbit is ~65km lower than that of QK-1…

29 Apr: China appears to be conducting some coordinated testing in VLEO with its Shiyan-25 (SY-25) and QianKun-1 (QK-1) satellites. Both were launched within a month of one another and are operating in the same orbital plane with nearly identical RAAN and inclination. SY-25’s orbit is ~65km lower than that of QK-1 which, as we know from Jack’s 10:1 article, means that SY-25 “gains” 650km on QK-1 every orbit. So every 4 days the two satellites pass one another on orbit with SY-25 being directly beneath QK-1. – China launched SY-25 on 20 Jun 2023 from Taiyuan using a LM-6. Initially it was in a 307 x 321 km x 96.6° sun-synchronous orbit (SSO). – As is typical with SY satellites, China released very little information regarding the satellite’s mission. Official sources noted the satellite will mainly be used to carry out new Earth-observation technology experiments. – SY-25 naturally lost altitude for its first week on orbit, then operators used propulsion to maintain altitude at ~302km from 14 Jul – 3 Aug. – Shortly after 3 Aug operators appear to have used propulsion to rapidly decrease altitude until ~9 Sep when SY-25 leveled out at ~271km where it has remained to the current day. – Less than 1 month after launching SY-25, China launched QK-1 on a CERES-1 rocket from Jiuquan. QK-1 was developed by a Chinese commercial company, CSPACE. – QK-1 is CSPACE’s first very low earth orbit satellite. It weighs ~200kg and is equipped with electric thrusters. – QK-1’s initial orbit was 486 km x 502 km with 96.6° inclination. The satellite maintained this SMA for the first month and then appears to have initiated a series of step-down maneuvers gradually reducing altitude to ~333km in late March 2024, where it remains today. SSO for 96.6° inclination is ~285km, so it remains to be seen if QK-1 will lower its orbit further. -SY-25 and QK-1 orbits are co-planar with equal inclination and RAAN…which we all remember from Jack’s Orbital Element articles it is the RAAN and inclination that define the orbit plane. – The two satellites also share similar Eccentricity. -Checking the SMA we find SY-25’s orbit is ~65km lower than that of QK-1 which, as we know from the 10:1 article and rule means that SY-25 “gains” 650 Km on QK-1 every orbit. – If you do a little math, we find that every 4 days the two satellites pass one another on orbit with SY-25 being directly beneath QK-1. See the Robin Planell’s relative distance plot provided and the green zero line. As time marches on, you can see the distance gets close (SY-25 zips underneath QK-1) every 4 days or so. China is poised to add VLEO spacecraft in the near term. CASIC plans to complete the launch of a nine-satellite cluster in 2024, and complete an orbital network of 192 satellites by 2027. By 2030, CASIC expects 300 operational satellites, providing diversified and real-time remote sensing services, and realizing global 15-minute response capabilities.

Issue 96 visual from page 9

Issue 96 visual from page 9

Issue 96 visual from page 9

Issue 96 visual from page 10

Issue 96 visual from page 10

Issue 96 visual from page 10