This 4 kilometer diameter feature near the edge of the South polar residual cap was recognized in Mariner 9 and Viking Orbiter images taken in the 1970s, but its origin could not be inferred.

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This 4 kilometer diameter feature near the edge of the South polar residual cap was recognized in Mariner 9 and Viking Orbiter images taken in the 1970s, but its origin could not be inferred.

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Size: 4827px × 3621px
Location:
Photo credit: © NASA/World History Archive & ARPL / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: 1970s, 4, 9, archival, archive, astronomy, cap, diameter, edge, exploration, feature, historical, history, images, inferred., kilometer, mariner, mars, nasa, orbiter, origin, planet, polar, recognized, residual, south, space, structure, viking