[Neocp_artsats] A10YNZf = NORAD 57804 = 2023-137E = SLIM booster

[Bill Gray]

    The elements for this object are,  overall,  a convincing match to 
those for those in the subject.  I rely on Space-Track elements for this 
object;  we haven't had observations since 2023 Nov 13,  perigee is low, 
  and atmospheric drag could have put it anywhere.  With any luck, 
it'll pull the object down and enable it to re-enter,  making it Not Our 
Problem anymore.

    Unfortunately,  the Space-Track elements are from mid-November. 
Used for A10YNZf,  you get positions that are off by over two degrees 
and the motion is only approximately aligned (which is why Sat_ID failed 
here).  So it seems Space-Track has lost track of this object,  too.

    I expect this object will make another appearance or two on NEOCP. 
After that,  I'll have enough data to compute TLEs for it.

    Ephemerides for SLIM itself,  by the way,  ran out on Horizons on 
Nov 24,  and I gather JAXA is unlikely to provide an extension.  I've 
computed ephems based on no maneuvers after Nov 24;  the result is a 
trajectory that hits the moon on Dec 25 at 20:36 UTC.  I both assume and 
hope it will actually go into orbit around the moon,  but the tweak to 
accomplish that will probably be small and the extrapolated trajectory 
good enough for IDing the object.

-- Bill