3
100 km Altitude — Equatorial OrbitDeploy and Spin Up the Rotor
The cable is unspooled from the deployment mechanism into a continuous loop encircling the Earth. Ground-based electromagnetic stations then accelerate the cable from orbital velocity (7,844 m/s) to 102% overspeed (7,999 m/s). The 2% excess velocity generates net outward centrifugal force — this is what will hold the stator platforms up.
Specifications
Orbital velocity at 100 km7,844 m/s
Target velocity (102%)7,999 m/s
Excess centrifugal acceleration0.384 m/s² per kg of rotor
Spin-up energy (20 tonnes)~640 GJ (~180 MWh)
Spin-up electricity cost~$9,000 at $0.05/kWh
Open Questions
- ?How do ground-based EM stations couple to a cable at 100 km altitude? Is this inductive, or does it require embedded conductors in the cable?
- ?How many ground stations are needed, and where should they be positioned?
- ?What's the unspooling procedure? How do you form a 40,000 km loop from a spool in orbit?
- ?What keeps the cable at 100 km during the spin-up window before excess centrifugal force kicks in?