Adrien Cater

On July 21, 1976, the media published the first color image sent back by Viking Lander 1 – which portrayed Mars with a very earth-like blue sky.

This error – quickly identified and corrected by NASA (the sky of Mars is actually a reddish-beige color) – was due to an error in the calibration of the onboard cameras. Amongst other hypotheses, it is believed that the color chart attached to the lander, used to give the cameras a ‘known’ neutral grey reference, was tainted with red martian dust. By unknowingly using a reddish-grey to calibrate the cameras, the images acquired a cyan tint due to counter-correction, yielding the blue sky.

This episode helped feed the various pseudo-scientific and conspiracy theories which surround most NASA anecdotes.

Seeing as that no-one has ever been to mars, one must question the notion of a faithful reproduction of an image, of which nobody has seen the original.