> Space is extremely cold, so achieving a super-conducting state is simply a matter of shielding the cable from the sun. Not quite so simple. If we're talking

> Space is extremely cold, so achieving a super-conducting state is simply a matter of shielding the cable from the sun. Not quite so simple. If we're talking about a cable near the earth, where the sun sometimes shines, there are always two heat paths -- from the sun to the cable, and from the cable to deep space. It's not easy, nor is a way self-evident, to make the cable fall to deep space temperatures at a reasonable cost, given that the sun is providing heat energy that must be diverted.