Space Domain Awareness @shell_jim

@s2a_systems Really appreciate these. I think consensus is that these objects are frozen effluent (LOX) from the upper stage passivation....but....if a microsat deployed among these objects, what a challenging situation .....

@planet4589 This breakup time would only be 24 minutes after launch (looking at GCAT launch time of 0823 UTC). Isn't that a bit too soon? (thinking apogee and payload release is nominally 1/2 orbit, so +45 mins from launch)??

🛰️ Satellite megaconstellation optical brightness compared to @IAU_CPS maximum recommendations So how are things looking for the international Dark and Quiet Skies initiatives to preserve ground-based astronomical observations? Not very good.... I'm working on a more extensive article, but among the "big four" constellations currently on orbit, China's GuoWang (aka Weixing Hulianwang Digui) is the most significant violator of the standard by a meaningful margin. (In fact, all four primary constellations are in violation of the recommended standard). The graphic below presents the average visual magnitude of individual tracks of GuoWang satellites since 01 Jan 2026, as taken by the Russian MMT system. (Data comprised of 427 tracks with 299,225 observations). Results summarized: These satellites on average exceed the maximum recommended brightness for their altitude by 2.96 visual magnitudes. Translating visual magnitude into a linear irradiance scale, or units directly related to the "digital counts" on a telescope's focal plane results in exceeding the brightness recommendation by 1524% !!! Orbital data (satellite altitudes) courtesy of @S4S_SDA via @SpaceTrackOrg , used with permission per ODR 24-002-4.

@JohnBarentine Original source materials -> x.com/shell_jim/stat…

Space Domain Awareness @shell_jim

a month ago

Not a good story. Over the past year, China continues to abandon numerous upper stages in long-lived low earth orbit,* counter to best practices for the long term sustainment of space. I initially sounded the alarm on this issue in April 2025, and further highlighted the issue

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@elonmusk @SciGuySpace FWIW here is the original source material as posted on X -> x.com/shell_jim/stat…

Space Domain Awareness @shell_jim

a month ago

Not a good story. Over the past year, China continues to abandon numerous upper stages in long-lived low earth orbit,* counter to best practices for the long term sustainment of space. I initially sounded the alarm on this issue in April 2025, and further highlighted the issue

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Here are some specific objects from Jan 2022 to date.

Not a good story. Over the past year, China continues to abandon numerous upper stages in long-lived low earth orbit,* counter to best practices for the long term sustainment of space. I initially sounded the alarm on this issue in April 2025, and further highlighted the issue in an August 2025 article and...the update is that things only continue to get worse. For those not familiar, the total orbital debris mass is a key variable for the long term sustainment of space. There is broad agreement that abandoning rocket body upper stages in long-lived orbits is NOT a best practice. In fact, all the major space-faring nations have acknowledged this (e.g., IADC signatories). However, as China's "mega constellations" launch rate increases, so does the number of abandoned rocket bodies in long-lived high LEO orbits. Russia and the US dominate the number of rocket bodies remaining in such long-lived orbits, rooted in historical practices from decades ago with minimal orbital debris concerns (graphic, bottom panel). HOWEVER, China's upper stages are estimated to have much higher masses on average. Although the US has almost double such objects, China's total mass of such objects is 252 metric tons and increasingly rapidly vs the US total of 57 metric tons (and holding steady). It's acknowledged there are some uncertainties in PRC upper stage dry mass values (Graphic, top panel). No matter, things are not going well. * "Long-lived LEO" is defined here as having a min perigee height of 600 km and an orbit height less than 2000 km (to preclude HEO rocket bodies) ** Object mass estimate use @planet4589 's dry mass from the GCAT *** Orbit data from U.S. Space Forces – Space (S4S) via space-track.org, used with permission per ODR 24-002-4.

3/n @Skyrocket71 's page on the probable identity of OBJECT A -> space.skyrocket.de/doc_sdat/linxi…

2/n It's constructive to examine the optical signatures of all PRC objects associated with this launch (2023-104), simply identified as Objects A-F in the US public catalog (space-track.org). A total of 6 objects have been cataloged from the launch; however, none of the objects are identified by name (SATNOs 57424-47529). Given HEO's NEI image of an object from the launch, it's constructive to examine the optical signatures of all objects associated with the launch. "OBJECT A" has a median optical cross section (OCS) of 13.9 dBsm, or ~24 m^2 (derived via a diffuse sphere model with albedo of 0.2). OBJECT A's optical cross section (OCS) is significantly larger than all of the objects from this launch for which optical signature data are available* (ref graphic). * Optical signature data is open source courtesy of the Russian MMT system.

1/n Thank you @heospace for facilitating "Positive ID" of a Chinese payload (OBJECT A - 57424) from this 2023 PRC launch with multiple payloads (launch 2023-104). x.com/heospace/statu…

HEO @heospace

a month ago

HEO has a #NoUFOPolicy. Objects we image leave with an identity and characterisation, as it is critical to identify space objects to maintain space and Earth safety. For example, this object is currently listed as Object A in public tracking databases, a designation assigned to

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@TransAstra_Corp @JoelSercel

@TransAstra_Corp Any chance you might be able to provide any hardware details? Number of apertures...sizes....integration times....matched filter technique, etc. THANKS for sharing!

@Skyrocket71 @stromgade THANK YOU for your years of dedicated work and the tremendous resource you’ve maintained for the global space community!

Have you investigated if the Russian "umbra tactic" is being employed? Past Russian RPOs in LEO exploit favorable solar illumination geometries for the "chaser" object...such that, when solar illumination would become favorable for the target to see the chaser, it is synchronized with the objects entering the earth's shadow (I've been wanting to complete some more recent analysis on this - so only speculating this may be occurring with this group)

Ug - "its" entirety

On July 7, 1976, President Ford issued National Security Decision Memorandum 333 (NSDM 333) "Enhance Survivability of Critical U.S. Military and Intelligence Space Systems." The growing dependence of the U.S. on satellite reconnaissance coupled with the growing Soviet ASAT threat prompted NSDM 333. NSDM called for the SecDef and DCI to balance the level of survivability of satellite systems commensurate with their mission importance. The NRO's response was quantified via the NRO's "Survivability Enhancement Action Plan," with the study completed in October 1976. The declassified study is a treasure of information regarding the assessed Soviet counterspace threats at the time, and an assortment of options to "Protect and Defend" (today's vernacular) against these threats. The full document in it's entirety may be downloaded here: nro.gov/Portals/135/do… (nro.gov URL) 2/2 #SpaceDomainAwareness #MilitarySpaceHistory #AlwaysContested #OurGrandparentsHaveBeenThereAndDoneThat! #ASAT

Military Space History #18: 1976: @NRO_gov Satellite Survivability Mandatory reading for all @USSpaceForce Guardians, and my reminder that space was "born contested!" It's been a while since my last "Military Space History" installment. This highlight comes courtesy of the NRO's annual "Sunshine Week" declassification and public release of historical documents, with this trove largely consisting of documents hitting the 50 year declassification milestone. 1/2

@s2a_systems Revisiting this - thanks again for the detailed chronology, etc!