Conrad Haas (1509–1576)
Was Zeugwart (equipment manager) and Arsenal Master at Sibiu (Hermannstadt), Transylvania, since 1551. Between 1529 and 1556, he wrote a book in which he described rocket technology, involving the combination of fireworks and weapons technologies. This manuscript was discovered in 1961, in the Sibiu public records (Pars Archivi Cititas Cibernensis Varia II -37). In this work Haas dealt with the technical details of rocket construction, explaining the working principles of a rocket. He described many rocket types, including the multistage rocket, bundled rockets, and the idea of modern spacecraft. His work also dealt with the theory of motion of multi-stage rockets, different fuel mixtures using liquid fuel, and introduced delta-shape fins and bell-shaped nozzles. In the last paragraph of his work, he wrote:
But my advice is for more peace and no war, leaving the rifles calmly in storage, so the bullet is not fired, the gunpowder is not burned or wet, so the prince keeps his money, the arsenal master his life; that is the advice Conrad Haas gives.
Before discovery of Haas' manuscript, the first description of the three-stage rocket was credited to the Polish artillery specialist Kazimierz Siemienowicz in his 1650 work, Artis Magnae Artilleriae Pars Prima ("Great Art of Artillery, Part One").