I wrote: > 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. Building on the typo hypothesis, if the ground track displayed in the launch control centre resulted from a set of orbital elements with a typo affecting a single digit of the inclination, such that 97.45 was entered as 94.45, then the true orbit can be recovered from the TLE I estimated from the track, simply by correcting the typo. Here is the TLE with the supposed typo: 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 Here is the correction: 1 79802U 12103.11415512 .00000000 00000-0 00000-0 0 06 2 79802 97.4500 182.0500 0002000 359.9726 179.8827 15.21000000 03 Adding this to the earlier plot shows that the point of intersection with the NOTAM (ascent) trajectory would be shifted farther south downrange: http://satobs.org/seesat_ref/misc/NK-2012-retrograde-3a.jpg Here is a view closer to the ascent trajectory: http://satobs.org/seesat_ref/misc/NK-2012-retrograde-4a.jpg Correcting the hypothetical error shifts the point of intersection from about 28.25 N, 124.5 E - about 1270 km downrange, to about 20.54 N, 124.39 E - about 2130 km downrange. Returning to David Wright's analysis, the caption beneath Fig.2 states: "A comparison of computer modeling of the Unha-2 launch from 2009 (red) and a potential Unha-3 launch (blue) that carries more fuel in its third stage. The solid lines show the launcher's trajectory; in both cases the launcher burns out and releases the satellite at range of about 2,100 km and an altitude of about 500 km." http://allthingsnuclear.org/post/20730991602/a-comparison-of-north-koreas-unha-2-and-unha-3 The agreement seems very good; however, there may be other trajectory simulations with different results, and the orbits I estimated from the LCC display and my plot of the NOTAMs track are not perfect, which affects the accuracy of the intersection points. Also, typo or not, the possibility that the track displayed in the LCC was faked cannot yet be excluded. Let's see what additional information North Korea provides, what additional evidence the journalists may extract, and whether anything reaches orbit. Ted Molczan _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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