known as a "Nemitz Ring-City", or "doughnut train"
is an improvement on the O’Neill space city concept first
developed by Gerard
K. O’Neill. The MetroCircus design offers incremental
growth and development of space city systems, allowing a learning
curve towards building full-fledged O’Neill space cities.
MetroCircus is a moving train on a circular track. It has
no front or back, it’s a seamless circle, or a circular track
full of cars. The train may use wheels on the track or be
a mag-lev system. The MetroCircus is inside a 1 kilometer
diameter circular trench or tunnel in an asteroid or small
planet, like Eros or Ceres. A train track is placed on the
outer wall of the trench or tunnel. The MetroCircus runs
on the track, producing simulated gravity by centripetal force.
main advantage of this design is that the moving structure
does not include the radiation shielding mass. This enables
far less massive structures and enables the early development
of large-scale habitable structures with simulated gravity
on the Moon or asteroids.
construction method can vary, from multiple cars to a welded
construction for a completely solid circle. The hull could
be up to several inches thick and made of nickel-iron or aluminium.
One kilometer in diameter is large enough to reduce or eliminate
debilitating coriolis effects. A one-kilometer MetroCircus
would run at about 150 kph to simulate 0.40 gravity.
get on and off the moving city, another track runs alongside.
A ‘commuter bus’ accelerates to match speed with the city,
then workers and materials are transferred.
thanks the Artemis Society International, http://www.asi.org,
a non-profit research foundation, Gregory Bennett, and Mike
Delaney for providing supporting technical analysis and MetroCircus