Date: 20 May 1971
A technician checks the soil sampler on an earlier generation of Mars lander -- Viking -- in this 1971 photo. Viking 1 became the first spacecraft to land safely on Mars on 20 July 1976.
The robotic arm scooped samples of the Martian soil, emptied it into a hopper on the lander, which analyzed it with three scientific instruments.
NASA's Viking Lander was designed, fabricated, and tested by the Martin Marietta Corp. of Denver, Colo., under the direction of the Viking Progect Office at Langley Research Center, Hampton, Va. The lander drew heavily on the experience gained from the Ranger, Surveyor and the Apollo Programs in the areas of radar, altimeters, facsimile, cameras, soil samplers, and landing gear.