Mariner 9 was more sophisticated than the earlier Mariners. The first Mariners were technologically advanced enough to get to Mars but could only fly by the planet; Mariner 9 was able to orbit Mars. In fact, Mariner 9 was the first probe to orbit another planet. Mariner 9 was equipped with two television cameras, and from its Martian orbit, beamed back 7,329 photos of the red planet. With its infrared spectrometer and ultraviolet spectrometer the probe studied the planet's atmosphere. An infrared radiometer measured surface temperatures.
From its position in orbit, Mariner 9 provided the most extensive data to date on the planet and laid the groundwork for the Viking mission that touched down landers on Mars. Mariner 9 offered scientists a revolutionary new look at the red planet, opening their eyes to fascinating features such as the gargantuan Olympus Mons volcano and the great Valles Marineris canyon, and piquing their interest in bizarre channels that looked as if they must have been formed by running water.
The new, sophisticated technology of an orbiting probe was the first step in making Mars a human destination.
