A vacuum airship, also known as a vacuum balloon, is a hypothetical airship that is evacuated rather than filled with a lighter-than-air gas such as hydrogen or helium. First proposed by Italian Jesuit priest Francesco Lana de Terzi in 1670,[1] the vacuum balloon would be the ultimate expression of lifting power per volume displaced. (Also called "FLanar", combination of F. Lana and the Portuguese word "flanar," which means wandering.[2])
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