Retrograde Rotor

Early versions of the launch loop assumed that a 14 km/s, 3 kg/m rotor moved prograde relative to the launch direction. However, with transformer track windings, rather than "drag" on the rotor, the coupling can be very efficient, and can also be phased 180 degrees. This offers three advantages:

1) The per-unit-length deceleration of the rotor is smaller

• the vehicle draws energy from a much longer length of rotor
• the "rotor acceleration motors" at the surface can restore velocity with less peak power

2) The deflection of track and rotor can be smaller

• less compliance needed for the stabilization cables

And potentially:

3) The rotor can be slower and heavier for the same lift

• more flux path for vehicle acceleration, less powerful and heavy vehicle magnets needed
• for example, 12 km/s and 4.7 kg/m

• this option will be explored in the future, for now assume 14 km/s and 3 kg/m