In the last three elsets posted for USA 129 r, #24681, ndot2 has changed from .01518 to .02490 to .01330 I have checked ndot2 and MM of all the elsets I have saved, and searched for an approximate best fit, using my decay program and its log function and graphs. The conclusions are highly speculative, and I have not investigated the effect on agreement with elset epochs (or observation fits) Except for the 1996 elsets, there is no indication of significant errors in MM, but the decay element, ndot2, ( which does not appear to deviate more than 10% from my smoothed function, averaged over a day or so) shows much larger variations in the elsets posted. Using SatEvo on the published elsets naturally shows a similar large variation, decay Jan.25-Feb.05. Substituting my smoothed values in the elsets, I get a smooth set of decay predictions, but there is a gradual progression from Feb.03 to Jan.29. The SatEvo evolution of the 97001.5 elset shows a decay rate more constant than my smoothed function (and the average of the posted elsets), with decay on Feb.03. This also leads to a Mean Motion on Jan.17 of 15.518, much less than the given 15.560. This looks like the behaviour of a large eccentricity orbit, whereas the posted (and smoothed) elsets behave like a less eccentric orbit, increasing the decay rate more rapidly. There could be many explanations to this: 1. SatEvo's atmosphere model is generally incorrect. 2. The atmosphere is currently much different from average 3. The density at perigee has increased considerably last two weeks. 4. The perigee is moving over the equator, making it lower. 5. The eccentricity of the rocket's orbit is lower than computed. I see no evidence for the first four points. Argument Of Perigee has moved from 138 down to 69 degres, according to elsets, still at quite high latitudes. Reducing e by 0.01 and using the smoothed 97001.5 elset, SatEvo gives ndot2=0.0150 and MM=15.5380 on 97017, closer to posted, and smoothed, elsets. If it is possible to fit an orbit with smaller eccentricity to available observations, the higher perigee would also explain the strangely low decay rate, which has puzzled analysts from the discovery, leading to speculations of a very large mass. Elsets posted ndot2 ndotdot6 MM e : 96365.52702280 .01097930 00000-0 15.12918679 0533247 96365.52701960 .01098464 00000-0 15.12923644 0537085 96366.58430690 .01220474 00000-0 15.15596164 0542171 97 01.50791800 .01244224 00000-0 15.17919842 0531505 97 02.56192110 .01020686 00000-0 15.20047638 0528127 97 04.53436490 .00959924 00000-0 15.23839338 0506368 97 06.56741040 .00954858 00000-0 15.27717527 0498408 97 07.54926320 .00964146 00000-0 15.29637502 0492390 97 08.52975180 .01097522 00000-0 15.31910590 0476076 97 09.50886640 .01078668 00000-0 15.33990437 0479853 97 11.78648514 .01625000 00000-0 15.40570033 0435000 97 11.85243630 .01446399 00000-0 15.40455303 0442942 97 13.47262092 .01510000 00000-0 15.45505325 0435000 97 13.53835740 .01510046 00000-0 15.45676063 0419000 97 15.79859908 .01435000 00000-0 15.52064688 0417000 97 15.86402340 .01433330 00000-0 15.52210943 0394003 97 16.82909254 .01518000 00000-0 15.55387590 0361000 97 17.15133102 .02490000 00000-0 15.56077282 0367600 97 17.15133102 .01330000 00000-0 15.56077282 0367600 Smoothed ndot2 and MM : 96999.5270 .0088 15.1419 97000.5843 .0090 15.1607 97001.5079 .0093 15.1776 97002.5619 .0096 15.1975 97004.5344 .0102 15.2364 97006.5674 .0109 15.2791 97007.5493 .0112 15.3008 97008.5298 .0116 15.3233 97009.5089 .0121 15.3465 97011.7865 .0132 15.4040 97011.8524 .0132 15.4057 97013.4726 .0142 15.4501 97013.5384 .0142 15.4520 97015.7986 .0158 15.5197 97015.8640 .0159 15.5218 97016.8291 .0167 15.5532 97017.1513 .0169 15.5640 Modified ndot2, SatEvo : 97001.50791800 .00930000 45818-4 15.17760000 0531505 97002.56211304 .00944832 48026-4 15.19736316 0523287 97004.53498376 .00974889 53259-4 15.23522713 0507553 97006.56837831 .01011840 67695-4 15.27558736 0490796 97007.55032268 .01032343 71594-4 15.29565822 0482468 97008.53096375 .01054022 75874-4 15.31611592 0473984 97009.51027969 .01076992 80590-4 15.33698302 0465333 97011.79006428 .01136375 93627-4 15.38740921 0444446 97011.85508996 .01138206 94016-4 15.38888827 0443833 97013.47867365 .01186434 10472-3 15.42661701 0428221 97013.54353366 .01188476 10519-3 15.42815738 0427583 97015.80947713 .01266641 12581-3 15.48373622 0404608 97015.87409737 .01269086 12645-3 15.48537481 0403931 97016.84257291 .01307388 13746-3 15.51032217 0393627 97016.90708221 .01310055 13819-3 15.51201067 0392930 97017.16504894 .01320878 14144-3 15.51879749 0390128 97024.78353371 .01823859 34880-3 15.75265625 0293826 97031.45609024 .03440123 19963-2 16.07188873 0165581 Modified ndot2 and e, SatEvo : 97001.50774305 .00929997 62649-4 15.17759675 0431506 97002.56192820 .00950420 66599-4 15.19741761 0423178 97004.53475331 .00992667 75933-4 15.23573386 0407087 97006.56800778 .01042263 87120-4 15.27708615 0389737 97007.54983073 .01068836 93491-4 15.29781033 0381048 97008.53030564 .01097376 10079-3 15.31904598 0372153 97009.50940250 .01128170 10913-3 15.34083225 0363053 97011.78841543 .01210652 13359-3 15.39407103 0340930 97011.85341268 .01213264 13435-3 15.39564650 0340278 97013.47614457 .01283590 15646-3 15.43613401 0323574 97013.54096433 .01286644 15761-3 15.43780003 0322889 97015.80513140 .01408355 20401-3 15.49870065 0297967 97015.86968900 .01412323 20579-3 15.50052161 0297226 97016.83713060 .01475882 23309-3 15.52845045 0285888 97017.15921977 .01498921 24387-3 15.53803142 0282012 97024.56742993 .02819396 15002-2 15.82717261 0170017 97028.75740449 .83712563 45316+1 16.41344923 0016512 ------------------------------------------------------------ -- b_gimle@algonet.se +46-8-7428086 (home) -- -- 59.22371 N, 18.22857 E AND member of : -- -- http://www.algonet.se/~b_gimle seesat-l / seesat-d -- -- bjorn@tt-tech.se +46-8-59095783 (office)-- ------------------------------------------------------------