Issue 124

21 June – 4 July: China continues to maneuver both SJ-21 (49330) and SJ-25 (62485) in extremely close proximity with one another and have likely made several docking attempts. The two satellites entered into merge conditions on 2 July and remain in that condition through the time of this report (4 July). The Joint Commercial Operations Cell (JCO) noted potential docking as of 2 Jul at 1108Z. Due to resolution limitations of ground based telescopes and other collection methods we will not know if SJ-25 has successfully re-fueled SJ-21 unless China releases a statement or we begin to see large maneuvers from SJ-21. Watch 30 June merge maneuvers video from s2a systems.

– Timeline (see graphics next page):

• 11 Jun: SJ-21 and SJ-25 begin RPO activity.
• 13 Jun: SJ-21 and SJ-25 operating in close proximity as to not be distinguishable by space domain awareness sensors. Merge condition exists for ~75-90 minutes.
• 14 Jun – 29 Jun: SJ-21 and SJ-25 maneuver away from one another, absolute distances between satellites varies from 5-200km.
• 30 Jun: SJ-21 and SJ-25 again appear as one object. Merge condition exists for ~6 hours.
• 1 Jul: SJ-21 and SJ-25 no longer in merge conditions and both make minor maneuvers.
• 2 Jul: SJ-21 and SJ-25 re-enter merge conditions.
• The Joint Commercial Operations Cell (JCO) has provided outstanding reporting throughout. The JCO called out the potential docking of SJ-21 and SJ-25 at 1108z on 02Jul. This matches with the equally awesome reporting from s2a systems.
• As of 4 July s2a systems noted the two objects remained in merge conditions.

3 Jul: China launched a Long March-4C with the Shiyan-28B 01 satellite Xichang. According to official sources, the satellite entered the desired orbit and “will be mainly used for space environment detection and related technical experiments”. As of 4 Jul SY-28 had yet to be entered into the space catalog and orbital information was unavailable. More to follow. Launch Video.

– This was only the second time China has launched a LM-4C from Xichang (the first time was with the lunar relay satellite Queqiao in 2018.) Observers noted the slow liftoff and larger fairing indicating a more massive payload.

22 Jun: China decreased the average altitude of its suspected inspector satellite, TJS-3 (43874), ~75km. The maneuver eliminated TJS-3’s 0.95°/day westward drift and the satellite is now located at 59°E longitude. After the maneuver the closest satellite to TJS-3 is China’s Beidou 11 (38091). If there are no further maneuvers from either satellite, TJS-3 will be ~68km from Beidou 11 on 6 July with optimal lighting conditions for imaging.

27 Jun: Based on orbital data it appears that at least 3 and as many as 6 of China’s 9 Yaogan-43 01 (60458-60466) satellites are no longer maintaining their orbits. As a result the previously consistent YG-43 01 formation has fallen apart as the problematic satellites have decreased their average altitudes due to orbital decay and are no longer maintaining their relative distances with the other YG-43 01 satellites. China’s Yaogan satellites are believed to be used by the Chinese military for Intelligence, Surveillance and Reconnaissance (ISR) operations.

– China launched all 9 YG-43 01 satellites into a 500km/35° orbit using a Long March 4B rocket on 3 Aug 2024. By 18 Sep 2024 China had maneuvered all 9 satellites into a formation in which the lead satellite was 30-32 minutes ahead of the final satellite in the train (see graphic). The average altitudes for all 9 satellites was ~ 496.5km with an average variance of <300m. As a result the formation remained stable with all 9 satellites staying in order (E, D, G, J, B, A, F, H, C) and maintaining their relative distance from one another.

-YG-43 01 remained in stable configuration until mid-March 2025 (almost exactly 6 months post launch). Beginning on 12 March China began to vary the maneuvering for several of the satellites.

-Maneuver Summary (graphs on following pages):

• The Good: China continues to maintain the orbits for 3 of the YG-43 01 satellites: 1) C (60460); 2) F (60463); and 3) H (60465). All continue to maintain their average altitudes of 497km and are regularly maneuvering (at least one maneuver per month).
• The Questionable: There are 3 satellites which have not maneuvered in over a month and are now orbiting below their historical average altitudes: 1) A (60458) last maneuver was 1 May 2025 and SMA is now 491.6km; 2) E (60462) had a maneuver gap from 17 Apr – 22 May in which its SMA dropped from 497.6km to 492.6km; it then conducted 2 maneuvers in late-May/early-Jun to increase SMA to 494km, but has not maneuvered since and SMA is now 492.1km; and 3) G (60464) which has a similar pattern as E, a maneuver gap from Mar-May, a series of SMA increases in early-May and then no maneuvers since 15 May. SMA for G is down to 492.3km.
• The Bad: Three of the YG-43 01 series have not maneuvered in over 2 months: 1) B (60459) last maneuvered on 19 Mar and its SMA has dropped to 488.1km; 2) D (60461) last maneuvered on 27 Apr and its SMA has dropped to 492.5km; and 3) J (60466) last maneuvered on 12 Mar and its SMA has dropped to 488.3km.

 

Editor’s Comment: We do not know the specific mission or capabilities of the YG-43 01 satellites. However, we do know that China launched them into a specific orbit and operated them in a well-maintained formation for 6 months. Beginning in mid-March the formation began to devolve and only 3 of the 9 satellites are now maintaining their relative positions with one another. If China had been using inter-satellite links to cross-cue between the 9 satellites, that capability is now sporadic at best as 6 of the 9 satellites have shorter orbital periods and are now lapping the 3 satellites maintaining their 497km average altitudes. As we’ve discussed before, operating at different average altitudes also generates a slight difference in RAAN procession and eventually the satellites will no longer be co-planar. This has already happened with YG-43 01 as there is now a RAAN variance of 1.9° between 01B and the three nominal satellites (01C, F & H).

27 Jun: While we’re on the subject of China’s YG-43 satellites, I thought it would be interesting to take a look at the 6 YG-43 02 satellites (60945-60950) and 3 YG-43 03 satellites (61617-61619). Recall that China launched the YG-43 03 satellites into a co-planar orbit with YG-43 02 making another 9 satellite formation in Oct 2024. China has maintained the orbits for 8 of the 9 satellites and all are maintaining their relative positions with one another. For these 8 satellites the average SMA is 496.8km with an average SMA variance is just 350m. The one exception is YG-43 02A (60945) which has not maneuvered in over 70 days (last maneuver was 19 Apr 2025). From Oct 2024 – April 2025 02A had been the lead satellite for the formation. However, without maintaining its orbit 02A’s average altitude has decreased to 489.8km and it now has a shorter orbital period than the other 8 satellites and is slowly lapping the formation. 02A also has a growing RAAN offset with the formation (currently at ~0.83°) and is no longer co-planar. Without 02A in the formation the duration from Lead to Final Trail satellite has decreased from ~15-20 minutes to ~ 12-13 minutes.

26 Jun – 5 Jul: On 26 June Russia released a sub-satellite from Cosmos 2558 which the 18 Space Defense Squadron has cataloged as “Object C” (64627). Initially believed to be debris, Object C has maneuvered and is undoubtedly an active sub-satellite. Watch Video from Marco Langbroek.

Recall that Cosmos 2558 is believed to be a Nivelir inspector satellite. It was launched in Aug 2022 into a co-planar orbit with a US reconnaissance satellite USA 326. Previous Nivelir satellites, Cosmos 2519 and Cosmos 2542, also released sub-satellites. These sub-satellites (Cosmos 2521 and Cosmos 2543 respectively) eventually released a third object at high velocity. In response USSPACECOM noted that Russia had “conducted a non-destructive test of a space-based anti-satellite weapon.”

Russian space operators last conducted orbital maintenance maneuvers for Cosmos 2558 (53323) in mid-April 2025. Over the past 2.5 months the satellite has naturally lost ~10km in average altitude (from 461.1 to 451.0 km).

From 26 Jun – 3 Jul Cosmos 2558 and Obj C were separated by 70-150km. After reducing Obj C’s average altitude on 3 Jul the satellites began to separate and will continue to do so as Obj C has a shorter orbital period than Cosmos 2558. As of 5 Jul the two objects were separated by over 4,000km. Eventually Obj C will lap Cosmos 2558 and they will have another close approach.

Cosmos 2558 and Object C are nearly co-planar with a US reconnaissance satellite USA 326 (51445). With orbital information from 5 Jul for Cosmos 2558/Obj C and 3 Jul for USA 326 (see McCants Catalog) the Point of closest approach between Cosmos 2558 and USA 326 is ~50km. Object C’s point of closest approach to USA 326 is ~80km. Both objects will have a close approach with USA 326 approximately every 4 days. It is important to note that these close approaches are not a result of Russian maneuvers, but rather are just orbital mechanics at work. However, Russia did intentionally launch Cosmos 2558 into a co-planar orbit with USA 326 and for years maintained Cosmos 2558’s orbit. With the satellites nearly plane-matched Russia could reduce the point of closest approach distance for either Cosmos 2558 (assuming it is still operational) or Object C using relatively small maneuvers.

Quick Look At Nivelir Satellites and Their US Companions

Using the information from the McCants Catalog I went ahead and compared the orbits of the 3 suspected Nivelir satellites (Cosmos 2558/2576/2588) with their USA objects of interest (USA 326/314/338 respectively). Results can be found in the table below. I then asked Jack Anthony for his take on what constitutes classifying 2 objects as being co-planar…in other words how close is close enough for inclination and RAAN? Jack noted one useful metric is to determine how much energy/fuel would be required from a “chaser” spacecraft to best match its “target.” Jack then computed the energy/fuel required to match the satellites’ average altitude (thanks Jack!)

 

Based on the valued in the spacetrak.org and McCants catalogs Cosmos 2558 remains the closest match with its corresponding USA satellite. The newly launched Cosmos 2588 is second with Cosmos 2576 having the greatest plane and SMA differences with its target US satellite.

 

Editor’s Note: the dates for the latest observations in the McCants catalog are noted next to the satellite name.

– Gone too Soon: Brig Gen Chandler (Fulcrum) Atwood

• “my best friend, my brother, my mentor, my Polaris star always there to guide me, and like the Polaris star I always thought he would be there”
• “Fulcrum was an amazing family man and warrior. He will be missed by so many.”
• “I treasured our decade-long friendship and grateful that I was able to see Fulcrum last Thursday. He was enthusiastic about his new role at U.S. Space Command, and I was excited to collaborate once more with a friend, coach, and mentor. Fulcrum’s presence will be deeply missed.”
• “Fulcrum was a great friend, mentor, and caring leader.”
• “He was one of the best.”
• “Fulcrum Atwood was an incredible leader. The very best this country can create…”

•  “One of the best/boldest warrior/leaders I’ve ever met. My younger brother. Incredible family man and one of the rare dedicated servant leaders.”
• “Fulcrum was a great person and this is a terrible loss for the community. He inspired many and will be missed”
• “Fulcrum was an outstanding leader, patient mentor, exemplar father, and dear friend. He will be missed by so many.”
• “Brig Gen Atwood leaves an incredible legacy.”
• “This news hits hard. Chad was a great classmate and represented the best in all of us.”
• “Excellent man and leader! Last words he shared with me this past Saturday was…‘I’m always here if you need anything’. He meant it.”
• “Brigadier General Atwood…helped shape the Space Force during its most critical foundational years. From standing up Space Delta 7 to his leadership at U.S. Space Command, he left an indelible mark on our service and everyone who had the honor of serving alongside him…I know we’ve lost not just an exceptional leader, but someone who embodied the very best of what it means to serve. His legacy will live on through the countless lives he touched and the strong foundation he helped build for our Space Force.”
• “He was an excellent leader, and (from my experience and view) earned the respect and admiration of the members of his units.”
• “His dedication to service, country, and the calling of a higher mission was evident in every step of his journey-from the parade grounds of Charleston to the forefront of our nation’s newest military frontier.”
• “General Atwood was a leader I inspired to be, a man who ALWAYS took the time for others. He would break away from official tours just to come talk to me to see how I was and encourage me in my new chapter.”
• “General Chandler ‘Fulcrum’ Atwood has left this world better than he found it. To have known and loved him for 23 years in service and life has been an honor.”
• “The man who really taught me what it meant to be a leader. One of those few people you meet in life who is genuine, sincere, and will tell you like it is for your benefit. He truly cared about each and every one of his people.”

• -Gone too Soon: Brig Gen Chandler (Fulcrum) Atwood continued

• “Gen Atwood was one of the great ones and absolutely beloved by all that came in contact with him…A true legend among Guardians and will be missed beyond measure! Godspeed General”
• “I cannot think of a day/week that we did not feel his leadership and involvement within the space enterprise.”
• “An excellent example of what all leaders in the military should strive to be.”
• “He cared deeply about making sure the next generation received personal guidance. He shaped the future of the USSF and will be missed.”
• “His infectious leadership was key the Center’s success. His legacy lives forever.”
• “He was one of the really good ones…led with ultimate integrity.”
• “I always looked to Gen Atwood as the epitome of a good officer and a great human.”
• “He was a visionary and dogged advocate for intelligence in the Space Force and beyond. He saw the potential in every one and was a constant cheerleader for his people.”
• “He was an incredible and treasured leader, a compassionate person, and a generous spirit. He made such a beautiful and lasting impression on those who had the honor of knowing him. I’m a better person for knowing him.”
• “He was a great man, an excellent leader, and a fierce fighter for his wingman and guardians.”
• “Fulcrum was one of the smartest officers I had the pleasure to serve with. What a huge loss to our nation.”
• “His leadership left a lasting impact on all who served with him.”
• “He was one of the best leaders I ever worked for.”
• “We will miss him so much. What an impact he made on us all.”
• “you were such a powerful presence, personality, leader, mentor, and friend. We are all better because of you.”
• “He was a great leader and one of my favorite commanders.”
• “An exceptional leader, patriot, mentor, friend, family man, and a true gem of a human being. The news this morning was rough to hear, and I don’t think there’s a time zone on this planet where someone isn’t grieving about him today. He was inspiring in every way, but especially when it came to the simple joys of life.”
• “Best commander I ever had…Your leadership won’t be forgotten.”
• “Fulcrum was an amazing leader and all around kind person. He will be deeply missed.”
• “A brilliant colleague who represented the best of our servicemen and women.”