It appears that the identifications of the objects that we have been tracking as IGS Opt 5 R/B [40539/15015B] and IGS 9 R/B [40382/15004B] are swapped compared to the identifications of the 18th SDS. Both Japanese IGS satellites were launched during the winter of 2015 into the same sun-synchronous orbital plane; IGS 9 on 2015-02-15T01:21:00 and IGS Opt 5 on 2015-03-26T01:21:00 on H2A rockets which left their rockets in orbit. The payloads and rockets were first observed in April 2015, and it appears that at that point their identifications were swapped. As of November 4, a TLE has become available for IGS Opt 5 R/B from space-track.org, and querying space-track.org reveals that orbital elements of IGS Opt 5 R/B are now available dating back to June 18, 2015, some 3 months after the launch on March 26, 2015. The temporal evolution of the orbital elements are consistent with those of a non-manouvering orbit, which rapidly decayed from the start orbit of 465 x 484 km to altitudes dropping below 400 km in January 2022, below 300 km on October 8, 2022 and below 200 km on November 1st. Space-track.org has a 60 day decay message predicting decay on November 3rd. The last TLE at November 2, 6:12UTC had a 129x143km orbit, so it has decayed since. Comparison of the IGS Opt 5 R/B TLEs from space-track.org shows that it was mis-identified as IGS 9 R/B [40382/15004B], which we last tracked in a 281x286km orbit on October 14. The IGS Opt 5 R/B TLEs from around that date are an excellent match to the IGS 9 R/B TLE. Comparison of the IGS 9 R/B elements from classfd.tle over the past 7 years shows that our elements for IGS 9 R/B track the space-track.org elements for IGS Opt 5 R/B extremely well. This confirms that the objects were swapped when we first observed them. I do not believe the identification of the payloads are swapped, as the IGS optical and radar satellites use distinct orbital altitudes. Regards, Cees _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Sat Nov 05 2022 - 07:30:04 UTC
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