Nasa missions-
Viking missions
Discoveries
Viking One was the first successful space craft to land on Mars. The Viking One worked on Chryse Planitia until November 1982. The 4 Vikings provided many new information about Mars' natural surroundings, environments and history. As a result it produce a clear overall image of Mars' cold weathered and the reddish volcanic soil under the thin dry carbon dioxide atmosphere. And lastly, providing evidence of ancient river beds and huge floods.
Technology
The technology was used for the orbiter is a imaging system, atmospheric water detector, infrared thermal mapper. And the technology used for the lander is a imaging system, gas chromatograph, seismometer, x-ray fluorescence, biological laboratory, weather instrument package (temperature, pressure, wind velocity), and a remote sampler arm.
Contribution to Our Knowledge
This Viking One mission made us understand how Mars was like billions of years ago and the discovery of river beds and floods suggests there may even be life forms or aliens from Mars. And that Mars has something in common with Earth with fact of Mars being carbon, nitrogen, hydrogen, oxygen and phosphorus.