Hello! So this is a rather stupid question, but I'm having trouble with gravitational fields, and can't exactly pinpoint what's going on. The total energy of an orbiting satellite is (due to ME = KE + GPE) (-GMm/2r), right? Well, I have found multiple statements that claim that the 'r' we use for GPE is the radius of the planetary object, whilst the 'R' we use for KE is the orbiting radius. How could this be? This means that the only possible way for ME to = -GMm/2r is for the r of the KE to match that of the GPE, which basically mean that the object MUST be on the surface, not orbiting. Pardon my ignorance, but this is driving me insane. I'm quite certain I got the R's wrong, if so I'd be really grateful for any clarification. Thanks a lot!