The Viking 1 lander touchs down on Mars' Chryse
Planitia (the Plains of Gold), becoming the first spacecraft to
land safely on another planet.
Viking 1 and Viking 2, which lands about 45 days
later in a different location, take photographs and collect other
science data on the Martian surface. The landers conduct three biology
experiments designed to look for possible signs of life. These experiments
discover unexpected and enigmatic chemical activity in the Martian
soil, but provide no clear evidence for the presence of living microorganisms
in soil near the landing sites.
Meanwhile, the orbiters continue imaging
and between them, image the entire planet at what was then high
resolution. The orbiters also conduct atmospheric water vapor measurements
and infrared thermal mapping. Viking 1 orbiter also flies within
90 kilometers (56 miles) of Phobos to take images of this larger,
inner moon of Mars.
Space Science Data Center