What Was NASA’s First Successful Planetary Probe Launch and What Planets Did the Mariner Space Probes Visit?
Mariner 2, the first successful planetary probe launch, was sent into Earth’s orbit on August 27, 1962. From there a rocket fired it on a 4-month journey to Venus. On November 28, 1965, Mariner 4 came within 540 miles (870 km) of Mars and sent back the first pictures of the planet’s surface. Mariner 6 and Mariner 7 (1969) both t
