1973: Mariner 10 (NASA)

Mariner 10 was a robotic space probe launched on 3 November 1973 to fly by the planets Mercury and Venus. It was launched approximately 2 years after Mariner 9 and was the last spacecraft in the Mariner programme (Mariner 11 and 12 were 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 t