Gaetano Crocco was a leading Italian aeronautical and aerospace designer, military officer (rising to the rank of general), and founder of the Italian Rocket Society in 1951. Crocco designed a number of airships in the early part of the twentieth century and switched to designing rocket engines in the 1920s. Among his many contributions to the theory of spaceflight was a paper in which he showed that a spacecraft could, in theory, travel from Earth to Mars, perform a reconnaissance Mars flyby (that is, not stop over in Mars orbit), and return to Earth in a total trip time of about one year.¹

 

Reference

1. Crocco, Gaetano A. "One-Year Exploration-Trip Earth-Mars-Venus-Earth." Rendiconti del VII Congresso Internanzionale Astronautico, Associazione Italiana Razzi (1956): 227-52; paper presented at the Seventh Congress of the International Astronautical Federation, Rome, Italy, 1956.