The article says, "His conclusion: The space elevator could be built with existing technology—minus the super-lightweight tether necessary to make the whole thi

The article says, "His conclusion: The space elevator could be built with existing technology—minus the super-lightweight tether necessary to make the whole thing work." In other words, it cannot be built with existing technology. NASA uses the idea of "Technology Readiness Level (TRL)" [1] to help assess speculative technology, the (obvious) idea being that each stage of deployment of a technology relies on passing tests at previous stages. On this scale, it's not clear to me that space elevators are at TRL1 ("basic principles observed and reported") yet. Space elevators depend critically on having a material that's strong enough to build the cable. Feasible designs for climbers, debris avoidance systems, power transmission and so on, can't make up for the lack of this critical component. [1] http://www.hq.nasa.gov/office/codeq/trl/trl.pdf http://www.hq.nasa.gov/office/codeq/trl/trl.pdf