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Viking 1 was the first US spacecraft to land on the surface of Mars and send back surface images. It launched from Cape Canaveral on August 20, 1975, landed July 20, 1976, and continued sending data until November 11, 1982. Viking 2 launched September 9, 1975 and operated on Mars until 1980.
The objective of these missions was "to obtain high resolution images of the Martian surface, characterize the structure and composition of the atmosphere and surface, and search for evidence of life." (https://nssdc.gsfc.nasa.gov/planetary/viking.html)
Exploring the Martian atmosphere meant measuring the wind in Mars' low-density atmosphere. NASA and the aerospace firm TRW (now part of Northrup-Grumman) looked for an instrument that could measure low wind in such an atmosphere. They chose a TSI anemometer, a small (about two inches long) pyrex glass rod coated in metal. The metal conducts an electrical current; the anemometer senses changes in the surrounding environment with data from the current.
TSI engineers worked with TRW to design the anemometers to withstand the shocks of space travel and extreme conditions on Mars' surface. TRW built an extendable boom and circuitry to hold the TSI sensors and protect them in operation on the planet.
Six TSI anemometers flew to Mars, three installed on Viking 1 and three on Viking 2.
According to the Lunar and Planetary Institute (managed by the Universities Space Research Association (USRA)), the Vikings missions "were phenomenally successful; most of what we know about Mars comes from the Viking mission." Among the things we learned was that wind on the surface of Mars averages 10-20 miles an hour. Viking measured "speeds of up to 113 kilometers (70 miles) per hour during dust storms." (https://airandspace.si.edu/exhibitions/exploring-the-planets/online/solar-system/mars/wind/)
Decades later, scientists are still analyzing the images and data captured by Viking. Happy anniversary, Viking!