NASA’S Viking program

The Viking program of the mid-1970s was a triumph in space exploration

NASA’S Viking program was the first mission to return numerous images and scientific data from Mars. It comprised two identical spacecraft – Viking 1 and Viking 2 – each with an orbiter and a lander.

Both launched using a Titan Iiie/centaur launch system. Viking 1 launched on 20 August 1975, reaching Mars after a ten-month journey. The orbiter took images and transmitted them to NASA, who used them to choose a site for the lander. On 20 July 1976 the lander separated from the orbiter and landed in an area called Chryse Planitia. For more than six years the lander took images and collected data from the surface. The orbiter’s fuel ran out on 7 August 1980, while the lander shut down on 13 November 1982 when a mistake during a software update caused its antenna to go down.

Viking 2 launched on 9 September 1975, reaching Mars orbit on 7 August 1976. The lander touched down in the Utopia Planitia on 3 September. Viking 2’s mission did not last as long as Viking 1; the orbiter shut down after a fuel leak about two years after arrival, while the lander had a battery failure after three-and-a-half years. Together Viking 1 and 2 provided more than 50,000 photographs of Mars.

Lander After circling the planet for landing site selection, the lander detached from the orbiter and landed on the surface via parachute. Star tracker The star tracker pointed the orbiter towards Canopus, a star in the southern constellation of Carina. THE VIKING SPACE PROBES A closer look at how the probes worked Solar panel Solar panels converted solar energy into about 620 watts of electrical energy for use by the orbiter. High-gain antenna The high-gain antenna communicated with ground control on Earth, sending back images and data. ©Dkimages Attitude control thruster This thruster on the Viking orbiter was a small rocket engine that steered the orbiter towards Mars. Low-gain antenna The low-gain antenna was a secondary antenna to be used if the high-gain antenna failed. Thruster engine This engine burned a liquid bipropellant rocket fuel mixture to propel the orbiter.