Security ... think about it!
To jump-start development, Nasa and Spaceward, a private foundation, are holding a $2m (£1.2m) competition this week to prove the concept, offering a prize to the team that can send an elevator just over half a mile into the sky at an average speed of 5 metres (16.4 ft) per second, on a cable suspended from a helicopter. The climb must be powered by a high-powered ground-based light or laser aimed at a cell facing Earth, a concept known as power beaming.