Re: Drag at Orbital Altitudes

[EMAIL PROTECTED] (Mike Miller) wrote in message news:<[EMAIL PROTECTED]>...

> 
> 2) How much would drag be reduced (percentage wise) if the station
> operated at 600km vs 400km? (For the sake of argument, say the station
> could get there in the first place.)

Hi Mike,

The atmospheric density is approximately 25 times less at 600-km
versus 400-km.  9.89x10^-14 kg/m^3 at 600-km and 2.62x10^-12 kg/m^3 at
400-km (based on MSIS atmospheric model with a solar flux [F10.7]
number of 120, taken from 2nd edition of SMAD).  Since atmospheric
drag is directly proportional to density, the drag force should
decrease by about a factor of 25.  (this ignores the small change in
velocity from being in a higher circular orbit)

Patrick Marsden