Abstract We present a general solution to the flatness problem by proposing a fundamental mechanical equivalence between mass and space. By treating space and mass as the sole universal identities, we derive a vacuum force $F_0 = 4\pi GM$ and a corresponding minimum acceleration threshold, that is $H_D=4 \pi G$, which is found to be the same as MOND's acceleration $a_0$. This framework establishes a mass-area equivalence $M = 4\pi R_L^2$, leading to a density parameter $\Omega$ that is identically equal to unity ($\Omega = 1$) across cosmic time. Our results naturally recover the Hubble relation and provide a theoretical basis for the observed flat geometry of the universe without requiring inflationary fine-tuning, offering a novel synthesis of gravitational flux and spatial pressure.