A satellite of mass 7500 kg orbits the Earth in a circular orbit of radius of 7.3(10^6) m (this is above the Earth's atmosphere). The mass of the Earth is 6.0(10^24) kg. What is the minimum amount of energy required to move the satellite from this orbit to a location very far away from the Earth? We are supposed to employ the Energy Principle to solve this problem, so we start with: K_i + U_i = K_f + U_f We know that K (at low speeds) = (1/2)*m*(v^2) and U = -GmM/r Using the Energy Principle, we know that K_f - K_i = U_i - U_f ΔK = -ΔU = -GmM[(1/r_f) - (1/r_i)] Since r_f is very large, ΔK = GmM(1/r_i) Using accepted and aforementioned values, ΔK = [6.7(10^-11) * 7500 * 6(10^24)]/[7.3(10^6)] This got me approximately 4.13(10^11)J, which is apparently incorrect. What am I doing wrong?