Mars panorama from Mars-4 (1)

The first in an armada of four spacecrafts launched in 1973, Mars-4 failed to enter orbit. During its flyby - on February 10, 1974 -, it returned 12 photographs from the 52mm "Vega" phototelevision camera, all through the red filter. It also returned 2 panoramas from the optical-mechanical cameras. Image data was returned digitally by pulse position modulation.