This is the proof test model of the Viking Mars Lander. For exploration of Mars, Viking represented the culmination of a series of exploratory missions that had begun in 1964. The Viking mission used two identical spacecraft, each consisting of a lander and an orbiter. Launched on August 20, 1975 from the Kennedy Space Center in Florida, Viking 1 spent nearly a year cruising to Mars, placed an orbiter in operation around the planet, and landed on July, 20 1976 on the Chryse Planitia. Highlighted in this image is the terminal descent engine of the Viking Mars Lander.