I am once again confused by the meaning of a material object not being able to exceed the speed of light in any frame. If the Earth is moving at 0.9C relative to some other galaxy in the universe, then would it be possible that a vessel had travelled between that galaxy and Earth? If so, wouldn't that vessel have had to accelerate to 0.9C to reach Earth? Now, if that vessel wanted to proceed past Earth to another destination, couldn't it once again accelerate to 0.9C? If not, why not, since it would reach Earth at a relatively low speed relative to Earth and could even go into orbit like any other object? In other words, doesn't any moving vessel reach a type of rest relative to itself and other objects in its frame such that acceleration to near-C velocity is repeatedly possible, even if such high velocity has already been achieved in a prior frame of motion?