I understand there are a group of tethered balloons that are more or less permanently stationed at 15,000 feet = 4.5 kilometers altitude in the USA south west. I presume there is occasional lightening damage and occasional loss. Since these are to detect drug traffic the lightening data may be difficult to access. Liftport and the Dr. Brad Edwards plan is to locate the first few space elevators in an ocean local near the equator where thunder storms are very rare. None the less rare lightening losses are expected, so the first elevator or two will not be designed for humans.<br />I agree, the effects of sprite, elve, blue jet, or other super discharge are not known, nor is it known how well the ribbon will conduct electricity. My guess is the ribbon will not conduct as well as copper or steel.<br />Could an ion engine maintain long term an altitude of 50 miles, while dangling a mile of #30 copper wire, with soon to be available technology, to study elves, sprites and blue discharge? Neil