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Question: Did Zuma complete at least one orbit?

CLOSE VOTERS, PLEASE NOTE: answers to What was the outcome of the launch of ZUMA by SpaceX, to the best of the public's knowledge? do not answer my question because

  1. they were written 2.5 years ago, only days after the launch itself and so can not capture any potential observations in the following years, and
  2. because they do not address my question about "at least one orbit" by Jonathan McDowell.

Zuma bumped NASA for the first launch of 2018 but the mission's status remains murky. Wikipedia says:

The US government has not publicly stated if there was a failure of Zuma and this secrecy has generated speculations on its purpose and its fate.

and Jonathan McDowell aka @planet4589 tweeted

Space-Track has cataloged the Zuma payload as USA 280, international designation 2018-001A. Catalog number 43098.

No orbit details given. No reentry date given, but for a secret payload it might not be. Implication is Space-Track thinks it completed at least one orbit

Yes it's a secret mission but answers to What kind of payload is Mission 1390 (Zuma) going to launch? tell us something and answers to How are military satellites with (apparently) classified TLEs still showing up on sat map websites? explain that secret missions are still tracked by amateurs. In fact active searches for radio signals from Zuma lead to the discovery of another lost satellite.

Are there any updates on Zuma's fate or possible subsequent sightings or detections of radio signals from it? Were one or more TLEs issued? If so, what do they imply?

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  • $\begingroup$ related in meta: Should questions with little information due to classified nature be asked? $\endgroup$
    – uhoh
    Commented Jun 5, 2020 at 1:17
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    $\begingroup$ @BowlOfRed no it does not because a) both answers there are 2.5 years old, written only days after the launch itself and so can not capture any potential observations in the following 2.5 years, and b) because they do not address my question about "at least one orbit" by Jonathan McDowell. I will include is information at the beginning of my question as well. $\endgroup$
    – uhoh
    Commented Jun 5, 2020 at 7:13
  • $\begingroup$ @BowlOfRed oops, at the end of it. $\endgroup$
    – uhoh
    Commented Jun 5, 2020 at 12:56
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    $\begingroup$ Any answer to this question is an answer to that question, and would be best answered by by updating the "Thus far, it has not been seen " part of the accepted answer. $\endgroup$
    – user20636
    Commented Sep 12, 2020 at 12:55
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    $\begingroup$ @JCRM from that answer I can't tell if the answer to "Did it complete at least one orbit?" is yes or no, but that's probably because there is so much there that addresses broader issues. Did it? I just need a boolean. $\endgroup$
    – uhoh
    Commented Sep 12, 2020 at 15:05

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From this answer and it's sources, we can conclude yes, Zuma completed at least one orbit.

While the outcome for the payload is publically unknown, it either separated or it didn't. If it separated before the deorbit burn it would have remained in orbit for several orbits. If it didn't separate before the deorbit burn it would deorbit with the upper stage, after one and a half orbits.

Given there have been no amateur sightings in over two years since then despite the interest, it seems most likely it didn't acheive a separate orbit, and likely landed in the Indian Ocean hafter one and a half orbits

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  • $\begingroup$ hmm... almost there but this answer depends on it either failing to separate or separating and being visible to amateurs! What if the whole point was to test a technique to make it low reflectivity in the visible spectrum? A small impulse followed by a few orbits and it could be anywhere, and if it is visibly dim and and radio quiet (it could beam in bursts to other military satellites in orbit, or use optical communication) it wouldn't have been detected in radio Zuma searches either. $\endgroup$
    – uhoh
    Commented Sep 13, 2020 at 9:46
  • $\begingroup$ see the following and their answers: Suppose Zuma wasn't “lost” — what would it take to detect it? and Is it possible for amateurs to determine the orbit of satellites and Are there any space probes or landers which regained communication after being lost? I feel that this answer is currently unfounded conjecture and that just saying "we can conclude..." isn't enough to demonstrate that this is conclusive. $\endgroup$
    – uhoh
    Commented Sep 13, 2020 at 9:47
  • $\begingroup$ you've missed the point @uhoh, see the second paragraph. Regardless of what happened, it completed at least one orbit $\endgroup$
    – user20636
    Commented Sep 13, 2020 at 11:51
  • $\begingroup$ I see, so provided that info is all correct, the only way it could have reentered in less than one orbit is if something really crazy happened; for example it separated and exploded, or if it retropropulsed and reentered sooner than the booster, both of which are more than unlikely. Okay satisfied, thanks! $\endgroup$
    – uhoh
    Commented Sep 13, 2020 at 11:58

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