Lava tubes and related flow structures were first recognized upon examination of
Viking orbiter images, and later identified using orbiter imagery from Mars Odyssey, Mars Global Surveyor, Mars Express, and Mars Reconnaissance Orbiter.
The left image is a portion of
Viking Orbiter 1 frame 070A13, the middle image is a portion of MOC frame shown normally, and the right image is the same MOC frame but with the brightness inverted to simulate the approximate lighting conditions of the Viking image.
(Copyright 1998 by Calvin J. Hamilton) Martian Atmosphere This oblique image taken by
the Viking orbiter spacecraft shows a thin band of the Martian atmosphere.
This oblique image taken by
the Viking orbiter spacecraft shows a thin band of the Martian atmosphere.
A 1970s photograph of the surface of Mars from
a Viking orbiter (left) appeared to trace the outlines of an ancient ocean.
The Viking orbiters saw dust devils in the mid-1970s, but researchers weren't sure how much dust they threw into the atmosphere.
In 1976
the Viking orbiters imaged a formation resembling a human visage; many people believed the Mars «face» was created by intelligent beings even after newer pictures exposed the hill as an eroded pile of rocks.
Combined,
the Viking orbiters and landers returned more than 50,000 photos.
It has a strikingly resemblance to a human face, especially in older images taken by
the Viking Orbiters.
Not exact matches
After studying
orbiter photos, the
Viking site certification team considered the original landing site for
Viking 1 unsafe.
Mars has a relatively well studied climate, going back to measurements made by
Viking, and continued with the current series of
orbiters, such as the Mars Global Surveyor.
Team members mate the
Viking 1 Lander (top) and
orbiter in Kennedy Space Center's Spacecraft Assembly and Encapsulation Facility on Dec. 11, 1974.
A long lull followed the
Viking mission; NASA launched its next Red Planet explorer, an
orbiter called Mars Observer, in 1992.
Mars has a relatively well studied climate, going back to measurements made by
Viking, and continued with the current series of
orbiters, such as the Mars Global Surveyor.
In the triptych at the top of the page, the image of Parana Valles on Mars was acquired by the
Viking 1
orbiter on September 13, 1976.