Superheavy flux tubes do not occur in the standard model, the simplest SU(5), and the observable gauge sector based on Calabi-Yau compactification of the heterotic string. We prove that topologically nontrivial string solutions exist naturally in the flipped SU(5) model. Both light strings and superheavy strings all behave like superconducting wires. The superheavy flux tube provides a welcome alternative to the adiabatic perturbations of inflationary cosmology for generating {delta}{rho}/{rho}{similar to}10{sup {minus}4} in an almost scale-invariant way, as desired for galaxy formation.