9D-USTE Spacetime Curvature Modulation: A Purely Geometric Mechanism for Anti-Gravity Propulsion without Exotic Matter

We propose a novel framework for anti-gravity propulsion derived from the dimensional reduction of a 9-dimensional Ultra-Spacetime-Time-Energy (9D-USTE) manifold. The fundamental spacetime structure is strictly defined as a product of a 3-dimensional macroscopic space and a compact 6-dimensional internal manifold (9D = 3 + 6), where time is treated as a dynamic evolution parameter rather than an additional spatial dimension. Unlike traditional Alcubierre-type metrics that rely on exotic matter violating energy conditions, our model achieves localized curvature modulation via the topological sign inversion of the 6D internal scalar curvature R₆. We demonstrate that a geometric phase transition in the internal manifold induces a controllable effective cosmological constant Λeff in 3D space, enabling repulsive gravitational effects. This purely geometric mechanism preserves causality, satisfies all energy conditions at the fundamental 9D level, and naturally reduces to classical gravity in the low-energy limit, providing a consistent and physically viable foundation for gravitational engineering and advanced propulsion.