பகிரப்பட்ட ஒலி

Imagine swinging a stone on a string in the dark. If you release the stone at precisely the right millisecond, it arcs perfectly around a distant boulder and returns directly to your hand without requiring any further effort. This is not just a thought experiment; it is the foundational astrodynamics governing humanity’s next great leap. The Apollo programme relied on short-duration excursions, but the modern era demands a sustained, multi-planetary presence.