1) The moving object progressively shrinks in length (from the outside stationary observer's point of view)
2) Time aboard the moving frame progressively slows (from the outside stationary observer's point of view)
3) The mass of the clock, and any other mass-containing object aboard the moving frame, progressively increases (from the outside stationary observer's point of view)
Certainly mass effects the fabric of space, but these effects wouldn't come into play here with such low mass objects. There isn't anywhere near the amount of mass here to bend the light beam's path. To bend a light beam's path, you need extreme amounts of mass, somewhere around the mass of the Sun. In fact, it was the bending of light coming from planet Mercury around the Sun which helped confirmed Einstein's GENERAL Theory of Relativity. Special Relativity only applies to things moving at a constant velocity (straight line, constant speed, basic inertial motion), while General covers it all.