Viking consisted of two twin orbiters and landers, with experimental chambers in the landers to conduct three biology experiments.

50 years ago, NASA sent 2 spacecraft to search for life on Mars – the Viking missions' findings are still discussed today

Source: space
Source Link: https://www.space.com/space-exploration/launches-spacecraft/50-years-ago-nasa-sent-2-spacecraft-to-search-for-life-on-mars-the-viking-missions-findings-are-still-discussed-today