In 1971, the Soviet landing capsule of Mars-3 became the first spacecraft to land on the red planet. Two cycloramic cameras were installed, mechanically scanning vertically with a resolution of 500 pixels, a complete sweep would transmit a 6000 line panorama and 4 lines per second.  The signal was to be relayed to Earth by the main spacecraft, which went into orbit around Mars.

Unfortunately, contact with the lander was lost about 20 seconds, and only 79 lines of data were received.  As on the Venera landers, the video signal would have been periodically interrupted by bursts of digital science telemetry.  In the portion of the signal that was received, the beginning portion is this digital telemetry, followed by about 15 seconds of video with the characteristic sync pattern sent during the retrace interval.

The images above are derived from a photo of the signal as it was printed on a paper plotter, and a glimpse of the signal was also shown in a Soviet documentary film.  Only one camera transmitted initially.  If the lander had functioned, the second camera was to be activated a day later.  With an orange filter in one, and a green filter on the other, the two cameras would have provided stereoscopic views and color information.

The image has sometimes been turned on it side, and the pattern of data in the initial telemetry burst has been misinterpreted by amateur enthusiasts as an image of the horizon of Mars.  The actual video signal starts a few seconds later.  It was gray and featureless, despite intense analysis by Soviet experts hoping to find some hint of the Martian terrain.

At the time, Soviet scientists proposed that the probe was damaged by a sand storm on Mars.  It is more likely that the telemetry signal was broken off because the orbiter was not well positioned.  Privately, one of the camera builders told me that he fears the video was blank because the capsule had tipped over, or perhaps was covered up by its parachute (recent possible location of the Mars-3 lander by NASA’s Mars Reconnaissance Orbiter suggests the parachute landed far away from the capsule).

After some discussions with Arnold Selivanov about this, he became interested in the problem again and published a new highly processed view of the video signal.  Is it a view of the Martian surface, or video signal noise?  Difficult to be certain, but still an historically interesting image.

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