Agreed about the view it represents. It's also how Orbit Architect depicts it so I am confident of the inclination it represents - 97°.5. Ted and I have just been discussing it offline. If you look at the video screen grab at http://www.zarya.info/Gallimaufry/Unha3SS.php#3D there is an 'extra island' in the Pacific about 150° azimuth from Taiwan. It is the satellite depicted on the orbit at about the time of separation from Unha 3. The location is close to the one I estimated on the original map near the top of my web page. It represents the situation about 10 minutes after launch and is consistent with the NOTAM areas and a dogleg by stage 3. The only question is whether it is genuine, and there doesn't seem to be anything to say it isn't Bob Christy On 11/04/2012 20:54, satrack@libero.it wrote: > I used Ted's TLEs to reproduce the same 3D perspective, for both 97.5 and 94.5 > deg. The first one seems to > match well. > > http://www.satflare.com/CmpInc97.html > > By the way, in the original picture, the orbit is plotted ECI, so the Earth > rotates with respect > to the orbit. This means that the same perspective is obtained only at the > correct time, which is > around 02.45 UTC, if using Ted's TLEs. > > At the previous link I uploaded also the workspace, in case someone wants to > work with these > views. > > Regards, > Simone > > >> ----Messaggio originale---- >> Da: bob@zarya.info >> Data: 11-apr-2012 18.49 >> A: "Seesat-L"<SeeSat-L@satobs.org> >> Ogg: Re: North Korea satellite: retrograde ground track displayed in launch > control centre >> I have used a piece of iPad software to reproduce the screen image >> showing the orbit. It tells me the inclination is 97°.4. >> >> There are copies of the two images here: >> http://www.zarya.info/Gallimaufry/Unha3SS.php#3D >> >> Bob Christy >> >> On 11/04/2012 02:36, Ted Molczan wrote: >>> Included in some of the video shot by journalists covering North Korea's > upcoming rocket launch, are launch control >>> display screens depicting a southbound ground track that to the eye looks > close to that of a sun-synchronous satellite >>> orbit. It has been discussed on the NSF and NK forums. I have been working > to estimate the orbit implied by the ground >>> track and to evaluate its consistency with the location of the launch site, > NOTAMs, and other information issued by >>> North Korea. >>> >>> The first images I saw had insufficient resolution or coverage to > confidently estimate the orbit. Fortunately, late last >>> night Charles Vick informed me of the following video, which is the > clearest I have seen yet: >>> http://www.youtube. > com/v/GpjGwG414rY&hl=en_US&feature=player_embedded&version=3 >>> The relevant scene appears for several seconds beginning at 01:56 elapsed > time. >>> Notice that the track begins on the other side of the Earth, rises above > the northern limb, then proceeds south over >>> China, the Korean peninsula and so on. The track appears to be a 3D > representation of the initial orbit around the >>> Earth. >>> >>> Based on a notional launch on 2012 Apr 12 at 02:30 UTC, and assuming a 500 > km circular orbit, I estimate that the orbit >>> is inclined approximately 94.5 deg: >>> >>> 1 79802U 12103.11415511 .00000000 00000-0 00000-0 0 05 >>> 2 79802 94.4500 182.0500 0002000 359.9726 179.8827 15.21000000 00 >>> >>> I estimated the inclination and RAAN by trial fit to a couple of reasonable > clear land marks visible on the display. >>> Since the orbit has been plotted as a 3D representation, there is potential > for parallax error in the ground track, but >>> it is mitigated by the more or less perpendicular vantage point. I estimate > the RAAN and inclination are accurate to >>> within several tenths of a degree. >>> >>> The epoch is of no special significance; it and the mean anomaly have been > chosen to place the orbit near the launch >>> site about 4 min after lift-off, which is a useful rule of thumb to > estimate the location of a newly satellite within >>> its orbit. >>> >>> I was especially interested to determine whether the 94.5 deg orbit > intersects with the 88.7 deg inclined ascent >>> trajectory, and whether the location is plausible for the 3rd stage firing. > Here is a plot of both trajectories: >>> http://satobs.org/seesat_ref/misc/NK-2012-retrograde-1a.jpg >>> >>> Here is a view near the ascent trajectory: >>> >>> http://satobs.org/seesat_ref/misc/NK-2012-retrograde-2a.jpg >>> >>> The point of intersection is near 28.25 N, 124.5 E, about 1270 km downrange > of the launch site, which seems to be in >>> rough agreement with the plot of altitude vs. range in this recent analysis > by David Wright (see Fig.2): >>> http://allthingsnuclear.org/post/20730991602/a-comparison-of-north-koreas- > unha-2-and-unha-3 >>> The orbit is not sun-synchronous, but better than the 88.7 deg orbit > implied by the NOTAMs, for the stated purpose of >>> the satellite. Sun-synch orbits precess +0.9856 deg/d. The 88.7 deg orbit > would precess at -0.1730 deg/d; the 94.5 deg >>> orbit would precess 0.5917 deg/d. >>> >>> To be precisely sun-synch, a 500 km orbit must be inclined 97.4 deg. The > apparent nearly 3 deg deficit may be an >>> indication of the performance limitation of the launcher. I do not exclude > the possibility that the displayed track was >>> faked to mislead the news media, but it should not have been more difficult > to produce a high-fidelity fake, assuming >>> the work was done by the trajectory specialists. Considering the relative > position of the numerals 4 and 7 on a keypad, >>> a simple, honest typo also cannot be excluded. >>> >>> Ted Molczan >>> >>> >>> _______________________________________________ >>> Seesat-l mailing list >>> http://mailman.satobs.org/mailman/listinfo/seesat-l >>> >>> >>> ----- >>> No virus found in this message. >>> Checked by AVG - www.avg.com >>> Version: 2012.0.1913 / Virus Database: 2411/4926 - Release Date: 04/10/12 >>> >>> >> _______________________________________________ >> Seesat-l mailing list >> http://mailman.satobs.org/mailman/listinfo/seesat-l >> > > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.1913 / Virus Database: 2411/4928 - Release Date: 04/11/12 > > > _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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