What Our First Close Look at Mars Actually Revealed

Not long after I graduated from college, I convinced my  father to come with me on a trip into thin desert air. He got on an airplane with me, something he’d only done a few times in his life, and we flew from Kentucky to Atlanta and then on to Tucson. We rented a car and drove deep into Arizona’s Old West country, to a hill over a kilo-meter above the San Pedro River Valley. There was a little hotel, which closed several years ago, at the Vega-Bray Observatory.

We checked in, then went to examine the telescopes. There was a 46-centimeter reflector beneath a roll-off roof, a couple of 30-centimeter Meades, and a half-meter Maksutov-Cassegrain. We zeroed in on a 20-centimeter Newtonian scope optimized for planetary viewing, which we moved to the observing deck just after dark. There was no tracking system or computer on it, just a sighting mechanism, which was all we needed. My father knew everything about the night sky.

He had spent a good deal of my childhood in the backyard with sky maps from Astronomy magazine tucked beneath his elbow. As much as my father would have loved training for a career in geology or astronomy, he’d needed a job to make ends meet, and he’d found one working with the state health department, just like my grandfather had. I’d seen the night sky many times through his oversized binoculars, which invariably wobbled in my hands, even though he always tried to hold them steady for me.

By this point in my life, I’d been to places like Lick Observatory and Mount Wilson Observatory. I’d spent my summers interning at NASA, and I’d visited the giant domes. I’d seen the data that state-of-the-art telescopes could collect flickering on computer screens. But there was something different about seeing the sky through a medium-range telescope at Vega-Bray.

That night in the desert, I sensed for the first time what Galileo and other early astronomers must have felt, something that’s been lost in the age of computers. Planetary science used to be an amateur enterprise. Before the dawn of the Space Age, every single practitioner had a direct relationship with the night sky. They were awake when others slept, alone with their science and their thoughts, enveloped by the vast physical world. To point the barrel of a telescope at a tiny dot in the sky and then see it as a world, that dot, that very one right there! Of all the thousand pinpricks of lights, that one is different. That one’s threaded by rings. That one has tiny moons, suspended like marbles. That little alabaster hat is a polar cap. That one is a world.

Standing there in the cold night air with my father, the telescope at my eye, I felt connected not only to Mars but to Galileo, to Huygens, to Newton, to Herschel. You can’t see something like that and not yearn to see it better. As I squinted, making adjustment after adjustment to the dials of the telescope, all I wanted was to fly up to it. Or at least keep the image still. I cursed the atmosphere that wouldn’t allow it—the same sky that keeps us alive, brings us rains, and softens our shadows. Even the rarefied air of Arizona tremored and swirled and maddeningly made heavens flicker away. Caught in the grasp of longing and frustration, I could understand why, by the twentieth century, we had to leave our own planet behind.

Two hundred and thirty-one days after Mariner 4 had launched, on the night of July 15, 1965, the tiny levers of the telex machine at JPL began ferociously clicking. Leighton must have felt a surge of emotion: The Mariner 4 pictures would be the first ever close-up images of anything beyond the moon, as the mission to Venus hadn’t taken any pictures. Leighton poignantly recognized the difference between knowing something about a place and actually seeing it, and so did his imaging team. As Bruce Murray, then only a postdoc, realized, “Looking at a planet for the first time . . . that’s not an experience people are likely to have very often in the history of the human race.”

The data packets were being flung from Mars to Earth, captured in the huge bowl of the tracking station at Goldstone Space Communications Complex in the Mojave Desert and transmitted across California via teletype to JPL’s Voyager Telecommunications section. To Leighton, it seemed that the bits of the picture were like pearls, strung kilometers apart on a string from Earth to Mars. The data rate was only eight and a third bits per second, so it would take eight hours for the first image to be fully transferred. Eight hours of nail-biting, eight hours of pure suspense.

The day before, as Mariner 4 was approaching Mars, the operations team had decided to relay a command, DC-25, with an updated stretch of code to initiate a platform-scanning action, which would identify the planet, followed by a second command, DC-26, which would ensure the camera stopped and didn’t record over the images. The data received before the code was sent suggested that the tape recorder had started and stopped, but there had been some anomalous errors. The tape recorder was also a flight spare, swapped in at the last minute because of a technical problem with the original. It would still be hours, possibly days, before the computers could assemble a real photograph, and now some were second-guessing whether the commands should have been sent, whether they might somehow confuse the computer.

Dick Grumm couldn’t stand the wait. He was in charge of the tape recorder, and he and a few other engineers began brainstorming ways they might check the data. It became a contest of sorts, and the winning idea was to print the single-stream data—groups of digits, indicating the brightness of each pixel—onto a reel of ticker tape. As the engineers began snipping the tape into strips and pinning them to the walls, Grumm popped over to a local Pasadena art store in search of six shades of gray chalk, one for each bit of the six-bit image. He ended up with a pack of Rembrandt pastels. “Chalk” was for schools, not artists, he discovered, and anyway, chalk wasn’t made in six shades of gray.

Upon his return, a massive paint-by-numbers artwork had been assembled and was now ready to be filled in. The Mariner 4 image that would eventually be shared with the public was black and white, but Dick’s ticker-tape interpretation with colors corresponding to the brightness scale came to life with pastels ranging from light-yellow ochre to burnt umber to Indian red. He had tried a purple color scheme, then a green one. But the red one seemed to best mimic the gray scale. It just happened to mimic the colors of Mars too.

When a jumpy public-relations team got word of what was happening, they went to find Grumm immediately. They didn’t want the restless press to seize upon some messy makeshift picture instead of an actual image of the Martian surface. Grumm refused to stop, arguing that this was engineering work, that he simply needed to verify that his tape recorder was working. They let him continue behind a movable partition, guarded by a security officer. But the press did find out, and they began to push into the room: the pencil-and-paper reporters, the television broadcasters, the radio men. With the gaps in the strips, the 200-by-200-pixel square frame was elongated into a rectangle, but soon, the edge of the planet was clear. Mariner 4 had taken the first close-up picture of Mars.

Even though the image was half planet, half blackness of space, it was still hailed around the world. The largest-circulation French daily printed the first of the final images, once it was rendered by the computer, across five columns of its front page. it’s marvelous, read the huge banner of The Evening News of London. As soon as the picture was placed into the hands of Pope Paul VI, he wrote across it, vidimus et admirati sumus—“we saw and we gazed in wonder.”

The camera had fog in it and some of the scan lines failed, causing streaks across the frame. “The resolution was awful,” recalls JPL engineer John Casani. “You really couldn’t see much.” But the images would presumably get better as Mariner 4 came closer and closer to the planet, imaging it as the sun struck the landscape more obliquely, picking up more contrast.

Among the streaks in the first two images, one dark area appeared to be real. It was twenty kilometers wide, shaped somewhat like a W. With the arrival of the third image, other possible features were identified, including a smaller smudge, just three kilometers across. Low hills perhaps? The first three images were released to the press for a quick look. As for interpreting the images, the center director urged patience. He reminded the public that the team’s collective human strength was reaching its limits.

Leighton began utilizing some electronic tricks to improve the quality, like erasing the clearly aberrant lines that arose from faulty scanning. But when he got to frame seven, he stopped in his tracks, struggling to believe what he saw. He called Jack James, the mission director, and the then project manager, Dan Schneiderman, into a small, secure room and showed them the tiny Polaroid of the video scope. It wasn’t at all what they had expected. They stared at the image in quiet disappointment. Eventually, Schneiderman uttered what they all knew to be true: “Jack, you and I have a twenty-minute jump on the rest of the lab to go out and look for new jobs.”

Scarcely anyone had been prepared for what frame seven revealed, much less what they saw in the next dozen images. “My God, it’s the moon,” thought Norm Haynes, one of the systems engineers. There were craters in the image, all perfectly preserved, which meant the planet was in bleak stasis. The crust hadn’t been swallowed by the churn of plate tectonics, but, more important, the surface hadn’t been worn down by the ebb and flow of water. Preserved craters meant there had been no resurfacing, no aqueous weathering of any kind resembling that of the Earth. As with the moon, it appeared there had never been any significant quantity of liquid water on the surface—no rainfall, no oceans, no streams, no ponds.

Stunned, the Mariner 4 team didn’t publicly release the images for days as they tried to understand the implications of what they were seeing. Finally, they scheduled a press conference. Lyndon Johnson, who had been following the spacecraft closely, hosted it at the White House. Just a few months earlier, he’d made the mission a centerpiece of his inaugural speech, addressing a country still reeling from John F. Kennedy’s assassination. He’d asked the crowd to think of their world as it looked from the rocket hurtling into space, how it was like “a child’s globe, hanging in space, the continents stuck to its side like colored maps.” He asked them to imagine their fellow passengers on a dot of Earth, to realize that we all have but a moment among our companions. Now, with the results of Mariner 4 in hand, that dot of Earth felt more isolated than ever before.

When Leighton took the podium in the East Room on July 29, two weeks after the flyby, he explained how man’s first close-up look at Mars had revealed the fact that large craters covered at least part of the surface. “A profound fact . . .” he said somberly, as his head swayed slightly to the left. He read from his notes about the nearly seventy craters in the images, ranging from five to 125 kilometers in diameter. Leaning into the microphone, he described how the density of their occurrence was “comparable to the densely cratered uplands of the moon.” It was “a scientifically startling fact.”

Upon seeing the pictures, Lyndon Johnson sighed, “It may be—it may just be—that life as we know it . . . is more unique than many have thought.” The mission’s instruments also revealed that the air on Mars was terribly thin. The pressure was minuscule—only a few thousandths of the pressure on Earth—which helped explain why the incoming meteors hadn’t burned up. The tiny whiff of carbon dioxide that had been detected with a spectrograph from Earth, and had been assumed a trace constituent, turned out to be essentially the entire atmosphere on Mars. The ground temperature was a frigid minus 100 degrees Celsius, and there was no evidence of any kind of protective magnetic field. The images were pockmarked all the way until they fell off the face of the planet.

The reality of the cold, hard, desolate world was beyond anything that scientists had imagined, beyond even the imaginations of the great science-fiction writers. “Craters? Why didn’t we think of craters?” Isaac Asimov, upon seeing the Mariner 4 images, reportedly asked a friend. The possibilities for the planet had disintegrated, our wild imaginings abraded to nothing. Humanity had spent centuries envisioning Mars as similar to the Earth, but Mars was bombarded, blighted, empty. On July 30, The New York Times declared, dispiritedly, what those at the press conference had struggled to say for themselves: Mars was probably “a dead planet.”

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From The Sirens of Mars by Sarah Stewart Johnson. Used with the permission of Crown. Copyright © 2020 by Sarah Stewart Johnson.