> If a drag factor in an elset is higher than the true drag experienced by > the object traveling through the upper atmosphere, then if the observer > looks for the object based on an ephemeris generated by a propagator > using the elset, then the observer will see the object later than > expected. Oh, now I see that I at first incorrectly interpreted your statement. Thanks for your answer! > Btw: Can someone explain how to derive the ballistic coefficient B (mass/(drag > factor*cross-sectional area)) from the Bstar drag term in the 2line elsets? The > Spacetrak report says something like: B=rho/(2*Bstar) with rho=2.461*10^-5 > kg/m^2/Earth radii. But with the Progress TLE above (Bstar=0.70872*10^-3 in > 1/Earth radii) I realy don't think that B=0.017.. kg/m^2 is right! The ballistic > coefficient of a Progress freighter should be around 200 kg/m^2 in the worst case. And, I forgot to multiply 'rho' by the value of Earth radius (~6378 km). So, the ballistic parameter for Progress is around 100 kg/m^2 for this 2line elset - really (too) high drag as you said, Walter. Cheers, Sebastian ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Wed Aug 29 2001 - 16:29:56 PDT