Viking program
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The Viking program consisted of a pair of identical American space probes, Viking 1 and Viking 2, which landed on Mars in 1976. The mission effort began in 1968 and was managed by the NASA Langley Research Center. Wikipedia
First flight: September 9, 1975
Start date: October 1968
Cost: roughly one billion dollars
Launched: 2
Manufacturer: Jet Propulsion Laboratory / Martin Marietta
Missions: Viking 2 and Viking 1