The first successful mission to Mars occurred in 1965, when Mariner 4 flew by the planet and returned 21 images. Although fuzzy and grainy, the pictures revealed a rugged, cratered terrain similar to parts of the Moon.
The technology for obtaining spacecraft photos of Mars and returning the information to the Earth has steadily improved since then. The HiRISE camera on the Mars Reconnaissance Orbiter can reveal surface features about half a meter in size.
The first image of Mars returned by the Mars TV camera on Mariner 4.
Mariner 4
NASA image
Improvement in Imaging
As the capabilities of spacecraft imaging systems advanced, the Martian surface could be viewed with increasing clarity and detail.
A. Image of Mariner Crater on Mars from Mariner 4.
Mariner 4
NASA image
B. View of the same crater acquired decades later by the Mars Odyssey spacecraft.
Mars Odyssey, THEMIS
NASA/JPL/Arizona State University image mosaic
C. An enlarged area from the previous image shows details of a small crater.
Mars Odyssey, THEMIS
NASA/JPL/Arizona State University image
D. The Mars Reconnaissance Orbiter reveals features on the small crater's rim.
Mars Reconnaissance Orbiter, HiRISE
NASA/JPL/University of Arizona image
E. A close-up from the previous image shows gullies on the crater rim. The central gully is about 30 meters (100 feet) across at its widest point.
Mars Reconnaissance Orbiter, HiRISE
NASA/JPL/University of Arizona image
