Over 50 years ago, on July 20 1976, NASA achieved something quite incredible for humanity and photography. At precisely 05:12 PDT the space agency successfully touched down on Mars with the Viking 1 lander, beginning the search for life on our celestial neighbor.
Just 25 seconds later, the spacecraft – now stationed on Chryse Planitia, a smooth, circular plain in Mars’ northern hemisphere – snapped the first ever image of the surface of the Martian world.
Forty minutes later, back at mission control, the image began to appear on the computer monitors, slowly forming line by line from left to right.
Dr Thomas Mutch (1931-1980), who led the Viking lander imaging team, later described the moment: “I studied the black screen, waiting for that narrow strip that would signal the first few lines of the first picture. And it appeared. A sliver of electronic magic.”
But instead of a rugged, red, dusty landscape embodying the amazing feat that the space agency had just achieved, the Viking 1 lander snapped a somewhat underwhelming black-and-white patch of rocky ground no more than a few meters square.
Aside from the sprinkling of rocks, the only real point of interest in the image was one of the spacecraft’s landing pads visible in the bottom-right corner. Despite this, Dr Mutch would time and again describe the picture as “incredible.”
While the act of beaming the first-ever image of the Red Planet’s surface back to Earth, 140 million miles away, was certainly groundbreaking, the image itself was never meant to be an awe-inspiring depiction of the world that had for so long captivated astronomers.
It was, in fact, a health check – a photographic thumbs-up to Dr Mutch and the rest of mission control that the Viking 1 lander had successfully completed its trip to the surface and was ready to begin collecting data from ground level.
The following day, Viking 1 captured its first-ever color image, finally revealing the rocky desert surface of the Red Planet as astronomers and the rest of the world had truly envisioned it.
To take this image, as well as the initial famous black-and-white frame, NASA mounted a pair of 16.1lb / 7.3kg facsimile cameras about a meter apart on Viking 1’s upper deck.
Instead of capturing a whole frame at once, each camera used a vertical array of photodetectors and a pivoting mirror to scan the Martian landscape line by line, operating like a slow fax machine to deliver a stereoscopic (3D) view.
For grayscale images, light passed straight to the detectors without filters. These took less time to record and transmit back to Earth – ideal for immediate post-landing checks – which is why NASA programmed Viking 1 to render the first image in black-and-white.
Color photos took significantly longer to process, as the cameras needed to scan the exact same scene three separate times, each time passing the light through separate red, green and blue optical filters.
Back on Earth, mission control computers – which received the image data at 250 bits per second via the Viking 1 orbiter – combined the three individual color channels into a single photograph.
By the late 1990s, Mars research vehicles had shifted from static landers like Viking 1 and later Viking 2 to mobile rovers able to roam the Martian landscape in their pursuit of signs of life.
In 1997, as part of the Pathfinder mission, NASA landed the Sojourner rover, which valiantly analyzed Martian rocks and soil for a total of about 85 Earth days – a month beyond its expected lifespan.
To this day NASA continues to explore the Red Planet with rovers like Perseverance, which landed in 2021 looking for evidence of past microbial life.
However, none of these mobile research missions would ever have been possible without Viking 1 and the initial grayscale image captured on its facsimile cameras 50 years ago, which provided the first vital clues about the planet’s regolith.
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