There is no need to speculate: The height decrease is nearly proportional to the drag term .00160759 (=.5*orbits/day^2). So after a week, the effect on pass time is .00160759*7*7 orbits. Multiplying by ~92 min period, this gives 7 min. For two weeks this gives 29 min, for 25 days a full orbit. This are relative to an orbit with NO drag. Because of the variability of atmospheric density, and tracking errors, we usually expect 15-20% error in the drag term, reducing the expected error to 1.5 min over a week. Quicksat prints this estimate on prediction lines, SkyMap shows it when an elset is reloaded (if the prediction date is set in advance) > Ted's last post with the most recent USA193 TLE noted a decay of ~890 > m/d. Can anyone speculate on how much error that introduces into pass > calculations over a week or so? ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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