03 Nov 1973: Mariner 10 heads to Mercury

On this day in 1973, NASA launched Mariner 10. It was the first craft to take close-up photos of Mercury, and the first to explore two planets (Venus was the other).

Artist’s rendering. (NASA via Wikimedia Commons)

More info on Mariner 10 and the program in general:

• Mariner 2 was the first craft to fly by another planet, Venus
• Mariner 9 is now in Areocentric orbit; it is predicted to crash into Mars in 2022
• Mariner 10 was the first craft to use the gravitational slingshot maneuver to bend and accelerate its course
• it was the last craft to explore Mercury until MESSENGER in 2011, which completed 4,000 orbits before crashing into the planet’s surface in 2015
• Mariner 11 and Mariner 12 were transformed into Voyager 1 (Jupiter, Saturn, Titan) and Voyager 2 (Jupiter, Saturn, Uranus, Neptune), both of which launched in 1977.