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.
2012 in spaceflight
Numerous significant milestones in robotic spaceflight occurred in 2012, including the landing of NASA's "Curiosity" rover on Mars in August, and the first commercial resupply missions to the ISS in May and October. The latter also marked the first fully operational use of SpaceX's Dragon spacecraft. Elsewhere in the Solar System, NASA's "Dawn" spacecraft completed its mission to 4 Vesta in September 2012, while China achieved its first asteroid flyby in December.