The US has been selling off its helium reserve, established in the 1920s to provide gas for airships – but even so, shortages have been occurring. Some scientists believe a finite reso... Read more
The bloon consists of a 129 m (423 ft) diameter and 96.5 m (316 ft) high sail that carries a 4.2 m (13.7 ft) diameter pod with room for four passengers and two pilots into near-space. While... Read more