.. or they are referring heights to a different ellipsoid On 7 February 2016 at 13:25, Brian Weeden via Seesat-l <seesat-l_at_satobs.org> wrote: > Yes, that would be my guess - JSpOC has it right, and the DPRK either > published the "desired" orbit, or messed up the maths. > > > > --------- > Brian > > > On Sun, Feb 7, 2016 at 1:11 PM, Marco Langbroek via Seesat-l < > seesat-l_at_satobs.org> wrote: > > > > > > > Hi all, > > > > I noted that the orbital parameters given in this DPRK announcement here: > > > > > > > https://soundcloud.com/martyn-williams-6/voice-of-korea-on-kwangmyongsong-4-launch > > > > ...namely perigee 494.6 km, apogee 500 km, inclination 97.4 deg > > > > is inconsistent with what we so far have from US tracking of the object. > > The > > first few sets of orbital elements published by JSpOC on Space-Track give > > (calculated from eccentricity and Mean Motion values) these values: > > > > - perigee 465 km, apogee 502 km, inclination 97.5 deg > > > > There is a clear difference in the apogee altitude here: 465 km according > > to > > JSpOC, 494.6 km according to the DPRK. > > > > Now, this could be due to initial inaccuracies in the JSpOC tracking > data. > > The > > first few elsets always have some variation and are less accurate > usually. > > > > Yet given the magnitude of the difference, I doubt this a bit. > > > > Instead, and assuming that the values in the DPRK announcement are not > > based on > > actual North Korean tracking but represent a pre-launch desired orbit, I > > wonder > > if this is perhaps an indication that the satellite ended up in an orbit > > with > > lower perigee than intended? > > > > - Marco > > > > > > ----- > > Dr Marco Langbroek - SatTrackCam Leiden, the Netherlands. > > e-mail: sattrackcam_at_langbroek.org > > > > Station (b)log: http://sattrackcam.blogspot.com > > Twitter: _at_Marco_Langbroek > > PGP key: http://tinyurl.com/kur7xm8 > > ----- > > > > > > _______________________________________________ > > Seesat-l mailing list > > http://mailman.satobs.org/mailman/listinfo/seesat-l > > > _______________________________________________ > Seesat-l mailing list > http://mailman.satobs.org/mailman/listinfo/seesat-l > _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Sun Feb 07 2016 - 12:53:00 UTC
This archive was generated by hypermail 2.3.0 : Sun Feb 07 2016 - 18:53:00 UTC