Mariner IV images returned

(Trivia note: some of these images can be seen pinned to the noticebard at Tidbinbilla in this February 1966 meeting of dignitaries present for the opening of Orroral Valley.)

Three different versions of image 01, with various enhancements in an attempt to bring out details.

Preserved by Les Whaley. Scanned by Colin Mackellar.

This JPL bulletin was sent to the DSN stations along with copies of the images –

Dated 4th August 1965, Mariner Mars '64 Bulletin 52 accompanied sets images for members of the DSN team. Click the image for a 700kb PDF file.

This scan is of a copy of the original release, hence the poor quality of the images.

Preserved by Les Whaley. Scanned by Colin Mackellar.

Here’s the main text of the bulletin:

This bulletin has been issued to provide each of you with reproductions of all the Mariner IV television pictures and the complete text that accompanied their official release.

Initial scientific interpretation of Mariner IV photography statement by television scientific investigators:

Professor Robert B. Leighton. California Institute of Technology, Principal Investigator
Professor Bruce C. Murray, California Institute of Technology
Professor Robert P. Sharp, California Institute of Technology
Richard K. Sloan, Jet Propulsion Laboratory
J. Denton Allen, Jet Propulsion Laboratory

Man’s first close-up look at Mars has revealed the scientifically startling fact that at least part of its surface is covered with large craters.

This is a profound fact which leads to far-reaching fundamental inferences concerning the evolutionary history of Mars and further enhances the uniqueness of Earth within the solar system.

Frame number 11 of the Mariner sequence must surely rank as one of the most remarkable scientific photographs of this age.

The existence of martian craters is demonstrated beyond question: Their meaning and significance is, of course, a matter of interpretation. The seventy craters clearly distinguishable on Mariner photos nos. 5 through 15, range in diameter from 3 to 75 miles. It seems likely that smaller craters exist, and there also may be still larger ones than those photographed, since the Mariner photographs, in total, sampled only about one percent of the martian surface.

The observed craters have rims rising a few hundred feet above the surrounding surface and depth of a few thousand feet below the rims. Crater walls so far measured seem to slope at angles up to about 10°.

The number of large craters per unit area of the martian surface is closely comparable to the densely cratered upland areas of the Moon.
If the Mariner sample is representative of the martian surface, the total number of craters of the sizes so far observed is more than 10,000 compared to a mere handful on Earth.

In appearance, the martian craters closely resemble impact craters on Earth, both artificial and natural, and the craters of the Moon. Craters of widely different degree of preservation and, presumably age, are distinguishable.

A few elongated diffuse markings are present on the Mariner photos but at this early stage of analysis no conclusions can be offered concerning them. On frame no. 13, one such feature looks like a part of the edge of a very large crater and, perhaps significantly, lies near the border of a martian dark area.

In southern sub-polar latitudes, where the season is late mid-winter some craters appear to be rimmed with frost, particularly in frame 14.
Some mention must be made of features looked for but not seen on Mariner photos. Although the flight line crossed several "Canals," sketched from time to time on maps of Mars, no trace of these features was discernible. It should be remembered in this respect that the visibility of many martian surface features. Including the “Canals,” is variable with time.

No Earth-like features, such as mountain chains, great valleys. Ocean basins or continental masses were recognized.

Clouds were not identified and the flight path did not cross either polar cap.

The following are some of the fundamental inferences to be drawn from the Mariner IV photos:

In terms of its evolutionary history, Mars is more Moon-like than Earth-like. Nonetheless, because it has an atmosphere, Mars may shed much light on early phases of earth's history.
Reasoning by analogy with the Moon, much of the heavily cratered surface of Mars must be very ancient — perhaps two to five billion years old.
The remarkable state of preservation of such an ancient surface leads us to the inference that no atmosphere significantly denser than the present very thin one has characterized the planet since that surface was born. Similarly, it is difficult to believe that free water in quantities sufficient to form streams or to fill oceans could have existed anywhere on Mars since that time the presence of such amounts of water (and consequent atmosphere) would have caused severe erosion over the entire surface.
The principal topographic features of Mars photographs by Mariner have not been produced by stress and deformation originating within the planet, in distinction to the case of the Earth. Earth is internally dynamic giving rise to mountains, continents and other features, while evidently Mars has long been inactive. The lack op internal activity is also consistent with the absence of a significant magnetic field on Mars as was determined by the Mariner magnetometer experiment.
As we had anticipated, Mariner photos neither demonstrate nor preclude the possible existence of life on Mars. The search for a fossil record does appear less promising if martian oceans never existed. On the other hand, if the martian surface is truly in its primitive form, that surface may prove to be the best -- perhaps the only -- place in the solar system still preserving clues to original organic development, traces of which have long since disappeared from Earth.

The Mariner photos will profoundly affect scientific views about the origin and evolution of planetary bodies in the planetary solar system

Below is an incomplete set of the images provided to Tidbinbilla. Higher resolution scans are available on request.