The Engine is a Gravity Modulator: How Everyday Machines Redirect the Direction of Gravitational Fall Within the Fundamental Speed Theory

We demonstrate that, within the Fundamental Speed Theory (FST), every engine functions as a gravitational modulator by creating a directed gradient in the FST motion field that locally redefines the direction of gravitational fall. We extend this to a universal principle: every material body possesses its own effective gravitational constant G_eff, modifying the G_eff of nearby bodies through its kinetic energy density. The effective gravitational constant of a planet is derived from angular momentum content as G_eff ∝ ρ·M·v_rot/R, normalized to Earth. This formula is validated against the Sun, predicting the solar-to-terrestrial gravitational strength ratio to within 4.2% of the observed value. Results: Jupiter 186.0, Saturn 26.6, Uranus 4.7, Neptune 7.6, Earth 1.0, Mars 0.075. Using the required orbital velocity v_required = √(2·G_eff·M_p²/(M_m·r)), and calibrating with Earth's Moon and Phobos, we obtain a linear relation between velocity deficit δ and recession rate: r_dot = 0.73·δ + 71.2 cm/yr, with critical threshold δ_crit = -97.5%. Applied to 26 moons across six planetary systems, 25 are predicted to recede. Triton, long believed to be decaying, is predicted to recede at +7.0 cm/yr. The smallest, closest moons recede fastest; the largest, most distant recede slowest. All predictions are falsifiable through astrometric monitoring. FST's central strength is explanatory economy: seven phenomena explained by one mechanism—the modification of G_eff by organized motion.