  A multi-purpose low-earth-orbit system of rings circling the earth - the "LEO
ARCHIPELAGO" - is proposed as a means of solving or bypassing many major
problems hindering man's quest to get into space. A fiber-optic ring about the
earth would be an initial testing and developmental stage for the ring systems,
while providing cash-flow through a LEO-based, high-band-width, world-wide
communication system. A Low-Earth-Orbit-based space-elevator system,
"Sling-on-a-Ring," is proposed as the crucial developmental stage of the LEO
Archipelago. Being a LEO-based heavy-mass lifter, rather than earth- or
GEO-based, it is much less massive and therefore less costly than other
proposed space-elevators. With the advent of lower-cost, higher-mass transport
to orbit, the options for further space development (e.g., communications,
space solar power, radiation dampers, sun shades, and permanent LEO habitation)
are greatly expanded. This paper provides an update of the Sling-on-a-Ring
concept in terms of new materials, potential applications, and trade-offs
associated with an earlier model. The impact of Colossal Carbon Tubes, CCT, a
material with high tensile strength, extremely-low density, and other favorable
properties and new technologies (e.g., solar-powered lasers, power beaming to
near-space and earth, and thermal-control systems) on the development of
associated LEO-Ring systems (e.g., "Solar-Shade Rings" and "Power Rings") is
also explored. The material's effect on the timeline for the system development
indicates the feasibility of near-term implementation of the system (possibly
within the decade). The Sling-on-a-Ring can provide a less-expensive,
environment-friendly, mode of access to space. This would pave the way (via
eventual operation at >1000 tonnes per day by 2050) for large scale development
of space-based technologies.
