Yet the dirigible airship never entirely went away. About 250 nonrigid blimps have been built for use as observation posts or advertising billboards. As a cheaper alternative to satellites, the European Space Agency is considering using solar-powered airships that would soar to a height of 20 kilometers. A reincarnation of the zeppelin company in Friedrichshafen, where the original airships were built, produces the New Technology Zeppelin, a small triangular-shaped craft that offers ''a tranquil tourist experience'' from the panoramic windows of its gondola. Despite this pedigree, the CargoLifter project, the most ambitious since the age of the zeppelins, faces large challenges.
German banks warn that it is a highly speculative investment.