1. The problem statement, all variables and given/known data On high 150km above the surface of Mars, there is satelite That is ciculating arround Mars. What's his bypass time? Radius of Mars is 3400km. 2. Relevant equations 3. The attempt at a solution I found equation like this : t= (2*r(R+h)^(3/2))/(sqrt(g0*R^2)) R=r+h r=3400km h=150km But when i try to calculate like this, i totally miss the actual time. I know bypass time(solution) is 110 minutes.