Issue 113

16 Jan 2025: On 6 Jan 2025 China launched a Long March-3B with the Shijian-25 (62485) satellite from Xichang. According to official sources, the satellite entered the planned orbit and will be “primarily used for the verification of satellite fuel replenishment and life extension service technologies”. Most interesting is the fact that China placed SJ-25 into a co-planar orbit with Shijiian-21 (49330.) SAST is the manufacturer for both SJ-21 and SJ-25 satellites. SJ-21 may be the intended refueling customer. Launch Video. – China maneuvered SJ-25 out of GTO on ~13 Jan 2025. China has placed the satellite at 120.2°E which is 0.1° west of TJS-11. SJ-21 is 28.6° away at 148.8°E. – SJ-25’s orbit is inclined 10.2° with a RAAN (orbit twist) value of 43.75°. SJ-21 is also inclined 10.2° and has nearly the exact same RAAN value of 43.745°. – Recall that for two objects to be co-planar they must have the same inclination and RAAN. SJ-25 and SJ-21 meet this criteria. Also recall that changing inclination or RAAN requires significant energy/fuel. – Why China initially located SJ-25 “near” TJS-11 is an open question. Examining their orbits, SJ-25 does not get closer than 450km from TJS-11. TJS-11 is inclined 5.0° with a RAAN of 322.3°…it is NOT co-planar with SJ-25. – China can relocate SJ-25 to conduct proximity operations with SJ-21 using only 22-32m/sec of fuel. The exact fuel usage will depend on how quickly China moves SJ-25 to intercept SJ-21. Thanks to Bob Hall and the COMSPOC team for their analysis. -Background on SJ-21

• SJ-21 launched on 24 Oct 2021. After launch China announced it was intended to perform debris mitigation experimentation.
• In late January 2022, SJ-21 docked/captured a defunct Chinese satellite to dragged it 300km out of geostationary orbit and into a “graveyard orbit.” The test demonstrated capabilities only previously exhibited by the United States and may have been the first capture of a non-cooperative target in GEO. See COMSPOC Video & Exoanalytic Video.
• SJ-21’s last maneuver occurred on ~10 Jul 2023 when it decreased its altitude ~64km. At the time its inclination was 9.2°. For the past 555 days SJ-21 has not maneuvered and its inclination naturally increased to 10.2°.

– Background on SJ-25: Per Andrew Jones:

• Shijian-25 was developed and manufactured by the Shanghai Academy of Spaceflight Technology (SAST), a major CASC subsidiary. The spacecraft will be used for “satellite fuel replenishment and life extension service technology verification,” according to a SAST statement.
• The Shijian-25 mission suggests China is focusing on advancing capabilities for maintaining and prolonging the operational lifespan of satellites already in orbit. Such capabilities can reduce costs and improve sustainability in space operations.
• While the mission may be focused on extending the lifetime of a civilian satellite, the capabilities could, for example, be used in the future to support military satellites through on-orbit servicing. The People’s Liberation Army is known to be working on the technology and training tools for on-orbit satellite refueling for both peacetime and wartime scenarios.

The fact SJ-25 is co-planar with SJ-21 strongly suggests SJ-21 is the intended refueling target. Both satellites were manufactured by the Shanghai Academy of Spaceflight Technology increasing the chances of collaboration between development/design teams. SJ-21 may have expended most of its onboard fuel during the debris mitigation demonstration and it may have been equipped for refueling in anticipation of SJ-25 development and launch. Time, and SJ-25 maneuvers, will tell.