Theoretical Framework for the Construction and Sustainable Operation of a Space Elevator —Top-Down Orbital Construction, Triple-Spacer Sliding Mechanisms, Twin-Shaft Cargo-Passenger Segregation, and Deep Space Exploration Efficiency—

This paper proposes a realistic and sustainable space elevator architecture that resolves structural fragility and extreme maintenance costs. By adopting top-down orbital construction, a non-collapsible space-anchored structure is achieved. The system integrates a triple-spacer sliding maintenance method, a mandatory twin-shaft design separating cargo and passengers, and a self-sustaining economic model. It further positions the elevator as a low-energy gateway for deep space exploration.