sentences: )"Viking 1" held the record for the longest Mars surface mission of days (over 6 years) or Martian solar days, until that record was broken by the "Opportunity" rover on May 19, 2010.Following launch using a Titan/Centaur launch vehicle on August 20, 1975, and an 11-month cruise to Mars, the orbiter began returning global images of Mars about 5 days before orbit insertion.