A space elevator is a proposed transport system connecting Earth's surface directly to space using a tethered cable. Primarily envisioned to reduce exorbitant rocket launch costs, it aims to provide sustainable and energy-efficient space access. The concept requires a geostationary anchor in space and a base on Earth, connected by a carbon nanotube or similar high-strength cable. Centrifugal forces from Earth's rotation keep the cable taut. Elevator cars, powered by solar energy or lasers, would climb this cable. Status: uncertain but decidableApproach: material research, modeling, fractal architecture