High Quality Content by WIKIPEDIA articles! Walter Hohmann (18 March 1880, Hardheim, Germany – 11 March 1945, Essen, Germany) was a German engineer who made an important contribution to the understanding of orbital dynamics. In a book published in 1925, Hohmann demonstrated a very fuel-efficient path to move a spacecraft between two different orbits, now called a Hohmann transfer orbit. He received his Ph.D. from the RWTH Aachen University in 1920.