Although the apogee/perigee difference of ISS is of the order of 10 km, the drag increase when perigee is near the equator should be noticable. The natural precession rate would be 3.8 d/day, and perigee at asc or desc node would occur at 47.5 day intervals. Reboosts appear to disrupt the smooth precession, and this period seems to be near 45 days over a long interval. > If it were closer to 28 days, I would suspect it to modulated by > the moon. Are there some other periodicities in the ISS equation > of motion that would have that period? > > Jim. > > On Mon, 19 Apr 2004, Moritz Heger wrote: > > > Hello everyone, > > > > This is slightly off-topic, as it does not directly stand in > > relation with visual satellite observing, but I do not know > > where to ask elsewhere. > > > > Looking closer on the BSTAR drag value of the ISS over time, > > I noticed that it is varying by around 10% with a period of > > about 20 days. ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Wed Apr 28 2004 - 04:06:46 EDT