I logged into Space-Track and immediately saw this message:

The 18th Space Control Squadron has confirmed the breakup of SL-12 R/B(AUX MOTOR), #36407. The time of breakup was at approximately 0206z, 22 May 2018. 18 SPCS is tracking approximately 60 associated pieces, all of which have been incorporated into routine conjunction assessment screenings. There is no indication that this breakup was caused by a collision with another object.

This appears to be 2010-007H and part of the Kosmos 2459, 2460, 2461 launch (Glonass).

I'm not used to reading these, and sometimes things are understated. Is this the beginning of the end of the world, or an unremarkable event, or something in between?

Screenshot of satellite breakup announcement Click for full size.

18 SPCS tweeted:

18SPCS confirmed breakup of SL-12 R/B (AUX MOTOR) #36407 on 22 May @ 0206z - 60 pieces being tracked - no indication it was caused by collision

According to this 18 SPCS tweet from last year:

JSpOC has transferred routine SSA ops to new unit: 18th Space Control Squadron (18 SPCS). Same SSA support under a different name!

Can I therefore conclude that this is a routine observation and therefore not "the end of the world"?

  • 1
    $\begingroup$ @bookmanB. Thank you for the suggestion, but I wanted to link to the other question, rather than the Kessler syndrome because of the nature of that question' "...the first noticeable consequences to the general public..." $\endgroup$
    – uhoh
    Commented May 23, 2018 at 8:17

1 Answer 1


Not the end of the world this time!

This appears to be one of a pair of Ullage Motors (#36406 and #36407) from the Block DM upper stage of a Proton-M launch vehicle. The Kosmos 2459, 2460, 2461 missions launched March 2010 and have/had several related pieces of debris that were expected to reenter.

This kind of occurrence is very commonplace - many launches leave rocket bodies and debris in decaying orbits.

See here for a summary of all the pieces of debris - 11 in total that appear to be from the same launch on 2010-03-01. (Note- at the time of writing this site has apparently not updated to reflect the status of #36407

  • 2
    $\begingroup$ Thanks for the speedy answer! With perigees of ~600 and ~950 km altitude, those would not decay quickly, and since the orbits are quite elliptical and they spend most of the time much farther from the Earth (apogee altitudes > 18,000 km), one would not expect them to reenter any time soon. $\endgroup$
    – uhoh
    Commented May 23, 2018 at 9:00
  • 2
    $\begingroup$ @uhoh Huh, you're right, I didn't pay attention to the Pe. If it's not caused by a collision, on-orbit break up could really only be due to the decay of some pressure vessel. However, a ullage motor bursting after 8 years seems unlikely. More investigation needed! $\endgroup$
    – Jack
    Commented May 23, 2018 at 9:50

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