A remote sensing satellite is deployed in a circular sun-synchronous orbit with inclination 96.85 degrees.
A. Calculate orbit altitude. I did this and got 349km.
B. The spacecraft coefficient is 200 kg/m^2. Solar conditions during the spacecraft launch are characterized by the solar flux F10.7 = 90. Is the orbit altitude sufficiently high for the spacecraft to operate through the estimated 2-year life time? What would be the spacecraft approximate lifetime if it is launched during solar maximum?
C. What is the maximum distance from the spacecraft to the horizon? I got 2139 km.
D. What is the maximum possible swath width? I got 12094 km.
E. What is the maximum possible time in view? I got 1560 seconds.
F. What is the ground speed of the subsatellite point? I got 7.3 km/s
G. The ground communications station is located at the satellite ground track. What is the communication time if the local conditions limit spacecraft visibility to elevation angles larger than 18 degrees?
The Attempt at a Solution
Assuming I got A,C,D,E,and F correct, I need help with B and G. For part B, I know the solar flux is related to the atmospheric density. If i get the atmospheric density I can use that, the radius of orbit and the ballistic coefficient to calculate the change in radius per revolution, and can calculate # of revs in a given time period since I know orbital velocity. I just don't know how to find the atmospheric density, rho, in the equation below which relates what I just talked about..
delta R(per rev) = -2*pi*(1/ballistic coeff)*rho*R^2
For part G, I have no clue where to start or what to do.