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In youth the chin was strong, the gaze steady. Now, more than 20 years later, the Face on Mars does not appear to be its old self. The Mars Global Surveyor (MGS) snapped two new photos (centre and reversed at right) of the much-touted ‘face’ — actually a mesa of resistant rock in the Cydonia region of Mars — during a close pass of the planet last Sunday (5 April).

Now you see it, now you don't: Mars Global Surveyor has shown the famous ‘face’ to be a rocky mesa. Credit: MALIN SPACE SCIENCE SYSTEMS

The new image was taken from a range of 444 km; each picture element has a resolution of 4.3 metres. Where some had imagined eyes, lips and a nose in the 1976 Viking picture (left), there now appear peaks, ridges and other features that show the face to be a natural geological formation.

The MGS is attempting several such targeted observations before resuming aerobraking operations in September to lower its orbit. And for the US space agency NASA, taking the picture was a relatively simple way to silence conspiracy theorists who claimed t hat it had been trying to cover up evidence of the former presence of an ‘intelligent’ being on the planet.

But targeting small objects with Surveyor's fixed-view camera is “technically very challenging”, says Michael Ravine of Malin Space Science Systems in San Diego, California, whose camera took the image.

Last week's attempts to photograph the much smaller Viking landers and Mars Pathfinder were not as successful. The camera track missed the Pathfinder and Viking 1 altogether, and the Viking 2 image was overexposed. But the MGS team will have two more chances before the end of April to get it right.