design was completed, it was difficult to find anyone who could manufacture its advanced design. The program managers were later praised for fending off pressure to go with a simpler, less advanced imaging system, especially when the views rolled in. The program did however save some money by cutting out a third lander and reducing the number of experiments on the lander. Overall NASA says that $1 billion in 1970s dollars was spent on the program, which when inflation-adjusted to dollars is about $ billion. Mission end The craft all eventually failed, one by one, as follows: The Viking program ended on May 21, 1983. To prevent an imminent impact with Mars the orbit of Viking 1 orbiter was raised on August 7, 1980, before it was shut down 10 days later. Impact and potential contamination on the planet's surface is possible from 2019 onwards. The Viking 1 lander was found to be about 6 kilometers from its planned landing site by the Mars Reconnaissance Orbiter in December 2006. Message artifact Each Viking lander carried a tiny dot of microfilm containing the names of several thousand people who had worked on the mission. Several earlier space probes had carried message artifacts, such as the Pioneer plaque and the Voyager Golden Record. Later probes also carried memorials or lists of names, such as the Perseverance rover which recognizes the almost 11 million people who signed up to include their names on the mission. Viking lander locations See also References Further reading On Mars: Exploration of the Red Planet Viking Orbiter Views of Mars The Martian Landscape SP-425 Analytical Chemistry feature article about the Viking spacecraft's scientific mission Viking '75 spacecraft design and test summary. Volume 1 Lander design – NASA Report Viking '75 spacecraft design and test summary. Volume 2 Orbiter design – NASA Report Viking '75 spacecraft design and test summary. Volume 3 Engineering test summary – NASA Report External links NASA Mars Viking Mission Viking Mission to Mars (NASA SP-334) Solar Views Project Viking Fact Sheet Viking Mission to Mars Video A diagram of the Viking and its flight profile Article at Smithsonian Air and Space Website The Viking Mars Missions Education & Preservation Project (VMMEPP) VMMEPP Online exhibit 45 years ago: Viking 1 Touches Down on Mars Spacecraft launched in 1975 Missions to Mars NASA programs Astrobiology Derelict landers (spacecraft) 1976 on Mars 1975 in Florida