1. The problem statement, all variables and given/known data An earth satellite is observed to have a height of perigee of 100 n mi and a height of apogee of 600 n mi. Find the period of the orbit. 2. Relevant equations (1) Period = (2*pi/sqrt(mu)) * A^(2/3) (2) rp+ra = 2A Where: Mu is the Standard Gravitational Parameter 4X10^5 (km^3/s^2) rp is radius of periapsis ra is radius of apoapsis A is the semi-major axis of an elliptic orbit. 3. The attempt at a solution I converted nautical miles to km, and used equation (2) to obtain A=648.2 km. (185.2km+1111.2km)=2A; A =648.2km I then plugged my value of A into the Period equation to obtain an answer of .744. I can't quite figure out the units for this number. It looks like it would be seconds, but that seems like a pretty unreasonable solution if it is. I know orbital periods are usually calculated in AU, but if I calculate in AU, I don't know what to do with the constant Mu, which is in km^3/s^2. Any help would be greatly appreciated! Thanks!