Mariner 10 launch. Mariner 10 spacecraft launching on top of an Atlas-Centaur rocket at Cape Canaveral (now Kennedy Space Centre), Florida, USA on 4 November 1973. This unmanned spacecraft was the first to fly past Mercury. It mapped nearly half of the planet's surface and measured its day and night temperatures. Contact with Mariner 10 was lost on 24 March 1975.