Scenario 1: A small mass is moving away from a large mass, slows down, reverses direction such that at t=0 it has an instantaneous velocity of 0 wrt height r. Scenario 2: An identical small mass is moving directly toward the large mass such that it arrives at height r with a velocity relative to r at t=0. So at height r at t=0 a small mass will be present, in scenario 1 it will be stationary for an instant, in scenario 2 it will have an instantaneous velocity. I'm wondering about the difference in the small mass momentum between the two scenarios... does a difference in momentum change the magnitude of the "gross" gravitational influence at r? In other words, does motion radially through the gravitational field effect the magnitude of influence? How are momentum variations accounted for if not? Does it work out that rate changes in radial momentum just balance out with the "gross" force of position to be the same "net" force? Is it improper to think of masses moving forward or backward through the gravitational field encountering different magnitudes of "gross" force compensated by momentum changes? Is it like the velocity of light being invariant - net gravitational acceleration experienced by a mass is always independent of its motion or momentum?