Oberth effect is named after a physicist who passed away in what year ?
Oberth effect:  The maneuver and effect are named after Hermann Oberth, the Austro-Hungarian-born German physicist and a founder of modern rocketry, who first described them in 1927. Hermann Oberth: Hermann Julius Oberth (] ; 25 June 1894 – 28 December 1989) was an Austro-Hungarian-born German physicist and engineer.
1989