Giuseppe Colombo & the Mariner 10 mission
"Giuseppe (Bepi) Colombo (1920-1984) was an Italian mathematician and engineer. He suggested that NASA's Mariner 10 mission could flyby Mercury repeatedly when choosing the right orbit. Following his suggestion, the mission indeed made three successful flybys of Mercury in 1974/75."
Mariner 10 was an American robotic space probe launched by NASA on November 3, 1973, to fly by the planets Mercury and Venus. It was launched approximately two years after Mariner 9 and was the last spacecraft in the Mariner program (Mariner 11 and 12 were allocated to the Voyager program and redesignated Voyager 1 and Voyager 2). The mission objectives were to measure Mercury's environment, atmosphere, surface, and body characteristics and to make similar investigations of Venus. Secondary objectives were to perform experiments in the interplanetary medium and to obtain experience with a dual-planet gravity assist mission.
Mariner 10 was the first spacecraft to make use of an interplanetary gravitational slingshot maneuver, using Venus to bend its flight path and bring its perihelion down to the level of Mercury's orbit. This maneuver, inspired by the orbital mechanics calculations of the Italian scientist Giuseppe Colombo, put the spacecraft into an orbit that repeatedly brought it back to Mercury. Mariner 10 used the solar radiation pressure on its solar panels and its high-gain antenna as a means of attitude control during flight, the first spacecraft to use active solar pressure control.