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.
Lunokhod programme
After the destruction of the original Lunokhod, Soviet engineers began work immediately on another lunar vehicle. "Lunokhod 1" (vehicle 8ЕЛ№203) was the first of two unmanned lunar rovers successfully landed on the Moon by the Soviet Union as part of its Lunokhod program. The spacecraft which carried "Lunokhod 1" was named "Luna 17". "Lunokhod 1" was the first roving remote-controlled robot to land on another world.