I was searching around for some images to use for a public talk and stumbled across some work that had been posted at unmannedspaceflight.com several years ago: a couple of different amateur takes on the Mariner 4 image catalog, the first set of photos returned from Mars, dating to July 14, 1965. These were long before my time and as such I find myself totally unable to imagine myself having no knowledge of what Mars looked like up close, and then seeing these photos. What would I have made of them? Would I have been disappointed that they looked cratered like the Moon? Would I have understood what I was seeing at all?
Before I show the photos, here's a context map. Yes, the base map actually has canals drawn on it. It's a 1962 Air Force map drawn specifically for Mariner 4 mission planning (learn more about that here).
Location map for the Mariner 4 Mars images
A base map shows the locations of all of Mariner 4's images of Mars, shot on July 14-15, 1965. Your eyes are not deceiving you: the base map on which the footprints are drawn has canals on it. This was, indeed, the map used by NASA to plan the encounter.
Here's one take on the complete catalog, assembled by Ted Stryk. He's worked his usual magic to bring out more coherent detail than would have been visible in processed images of the time.
NASA / JPL / Ted Stryk
The Mariner 4 image catalog
A little commemorative compilation of the Mariner 4 images, along with the nearest decent context image of the correct hemisphere in the International Mars Patrol collection in the lower right hand corner.
Piotr Masek asked what really was visible in the images, and produced comparisons of most of the Mariner 4 photos to later Viking ones. Click on the photo to see ten more Mariner/Viking comparisons. Would we have come to different conclusions then, if we'd only been able to see slightly more clearly?
NASA / JPL / Piotr Masek
Mariner 4 images with Viking Orbiter comparisons
Mariner 4 didn't only see cratered terrain, but the images lacked the clarity needed to see Mars' more Earth-like features. This is Mariner 4 image #3. Click through to see many more such comparisons.