Robot Explorers: US Unmanned Space Missions: page 9

In 1975 another "first" was undertaken. With the advent of new and improved technologies and more sophisticated instrumentation, the U.S. set out to actually land an automated spacecraft on another planet - Mars.

Viking 1 and 2 were launched from Kennedy Space Center on August 20th and September 9th, respectively. Their mission - to study the red planet from orbit and to land two Landers on Mars to study the composition of the surface and to continue the search for signs of life, past or present, on the planet.

Although no one expected to see a Martian metropolis, it was hoped that the biology experiments on the landers would at least find evidence of primitive life.

Viking 1 went into orbit around Mars on June 19, 1976. During the orbit exciting new images were transmitted back to Earth. This huge volcano, Olympus Mons, is more than 17 miles high and 350 miles in diameters. But as fascinating as these images were, the real excitement was about to begin.

On July 20, 1976 Viking 1 Lander became the first spacecraft to successfully touch down on another planet. This is the first color picture taken on the surface of Mars, in an area known as the Plains of Gold. photo showed a bleak, rusty-red landscape. Fine red dust from the Martian soil gives the sky a salmon hue.

Small samples of the red soil were tested in three different experiments designed to detect biological processes. Although some of the test results seemed to indicate biological activity, later analysis showed that this activity was inorganic in nature and related to the planet's soil chemistry. Viking found no evidence of organic molecules.

Viking 2 touched down on Utopia Planitia six weeks after Viking 1 had landed. The second lander had a view of a more rolling landscape, one without any sand visible dunes.

The Viking Landers became sophisticated weather stations, recording wind velocity and direction as well as atmospheric temperature and pressure. Few weather changes were observed. The highest temperature recorded was 7º F at the Lander 1 site in summer. The lowest temperature, -184º F, was recorded at the more northerly Lander 2 site during winter.

Near-hurricane wind speeds were measured during global dust storms, but since the atmosphere is so thin, wind force is minimal.

viking2mars.jpg (34759 bytes)

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Copyright ©2004 Colleen Gino

Images courtesy JPL and NASA.