The first colour photograph taken on the surface of Mars taken by Viking 1, the first landerViking 1, 21 July 1976Vintage chromogenic print on resin coated Kodak paper, 25.4 x 20.3 cm (10 x 8 in)Footnotes:Launched on Augt 20, 1975, Viking 1 became the first unmanned spacecraft to land successfully on Mars eleven months later on July 20, 1976.This colour picture of Mars was taken July 21 - the day following Viking 1's successful landing on the planet.The local time on Mars is approximately noon. The view is southeast from the Viking. Orange-red surface materials cover most of the surface, apparently forming a thin veneer over darker bedrock exposed in patches, as in the lower right. The reddish surface materials may be limonite (hydrated ferric oxide). Such weathering products form on Earth in the presence of water and an oxidizing atmosphere. The sky has a reddish cast, probably due to scattering and reflection from reddish sediment spended in the lower atmosphere. The scene was scanned three times by the spacecraft's camera number 2, through a different colour filter each time. To assist in balancing the colours, a second picture was taken of z test chart mounted on the rear of the spacecraft. Colour data for these patches were adjted until the patches were an appropriate colour of grey. The same calibration was then ed for the entire scene.