Viking 1
Viking 1 was the first of two spacecraft (along with "Viking 2") sent to Mars as part of NASA's Viking program. On July 20, 1976, it became the second spacecraft to soft-land on Mars, and the first soft lander to successfully perform its mission. (The first spacecraft to soft-land on Mars was the Soviet Union's Mars 3 on December 2, 1971, which stopped transmitting after 14.5 seconds.) "Viking 1" held the record for the longest Mars surface mission of days (over 6¼ years) or Martian solar days, until that record was broken by "Opportunity" on May 19, 2010.
Cape Canaveral Air Force Station Launch Complex 12
On 27 August 1962, Mariner 2 was launched by Atlas-Agena B 179D, the first spacecraft conduct a successful flyby of another planet when it flew past Venus on 14 December 1962. On 28 July 1964, Atlas-Agena B 250D launched Ranger 7, which was the first fully successful Ranger mission. On 28 November 1964, Atlas-Agena D 288D launched with Mariner 4, which provided the first close-up pictures of Mars.