The multi-stage space elevator offers an alternative to the single-ribbon design, making it possible to construct the elevator with present-day materials. Details of the multi-stage design and technology are presented, including stability calculations, prototype planning and cost estimates.

The subject selected for this 2013 study is the Space Elevator Tether Climber. The objective of the one year study was to survey current concepts and technologies related to tether climbers, identify critical issues, questions, and concerns, assess their impact on the development of space elevators, and project towards the future. The following are a few of the conclusions: * The study used the concept of "constant power" as a baseline because of its ability to lower design requirements on the tether climber. * The mass breakout of 6 MT for a climber and 14 MT for customer payloads seems feasible. The estimate is that with a travel time of one week to GEO seven tether climbers can be on a tether simultaneously. * The communication architecture should be integrated into the space elevator infrastructure and nodal layout. * Solar power, as the sole source, appears achievable. * The use of laser power as the sole source also seems achievable.