Alan correctly points out what I MISSED in my initial post. I looked at the mean motion and the eccentricity but failed to mentally calculate the PERIGEE. Had I done that, or used an elset with the perigee and altitude, I would have known that drag was a major factor. Thanks for the "education" Alan. Ron At 09:08 AM 3/22/98 +0000, you wrote: >Regarding his binocular obs of this GPS PAM-D, Ron Lee ><ronlee@pcisys.net> writes >>... >>21892 >>1 21892U 92009C 98080.88376902 .02011925 -67434-6 80885-3 0 5618 >>2 21892 34.4286 7.5870 0932503 256.3201 93.2584 14.2112852414899 >>... >>Just looking at the elset with a mean motion of 14.2, sure seems odd >>that it is due to decay around 21 April. > >But its perigee is around 150-155 km and it is certainly feeling the >drag. It passed through mm=12.0 on December 21, mm=13.0 on February 14 >and mm=14.0 on March 16. An evolution to decay on April 21 has it >reaching mm=15.0 on April 9 and mm=16 about 28 hours before re-entry. In >fact, my prediction of April 21 (as for many of the dates in my latest >decay list) assumes that the mean atmosphere density will decrease a >little from its recent high value - if current conditions continue, its >decay could occur a few days earlier still. I include current elsets for >this in both dklist.tle and select.tle, available via my WWW page. > >Alan >-- > Alan Pickup | COSPAR site 2707: 55d53m48.7s N 3d11m51.2s W 156m asl > Edinburgh | Home: alan@wingar.demon.co.uk +44 (0)131 477 9144 > Scotland | SatEvo satellite page: http://www.wingar.demon.co.uk/satevo/ > > >