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The picture was grainy and ill-defined, a blur of white curving across a black background. It would take months of painstaking analysis to determine what it really showed. But one quick glance gave the scientists at Caltech's Jet Propulsion Laboratory the most important message of all: from 135 million miles in space, their spacecraft, Mariner IV, had sent home the first closeup portrait man has ever made of the far-off planet Mars.
While all the world watched and waited, the ambitious timetable of U.S. space exploration had been put to its most demanding test. And the high, undulating whine of JPL's computers seemed to change subtly into a cry of exaltation. Mariner had made it.
This was the triumphant climax of an eight-month experiment. The picture pulsing back across the far reaches of space marked the final payoff. For those pictures, JPL's boss, Physicist William Pickering, and his crew had sweated out Mariner's launch from a Cape Kennedy rocket pad; the agile combination of men and computers in the Pasadena lab had solved complex equations of trajectory with split-second precision; the members of the Mariner team had kept a close watch as they monitored their spacecraft's every signal.
By week's end, three pictures were made public. The second and third shots, like the first, showed broad, desertlike areas but few outstanding surface markings. The first photo had been snapped from a distance of 10,500 miles, catching the planet at 11 a.m. Martian time. Through a slight trajectory miscalculation, Mariner was 500 miles off its intended course and caught Mars in a slightly different pose than expected—the camera focused on a 192-mile segment in the Martian area known as Phlegra. The next shots were made as Mariner swept past the eastern edge of Trivium Charontis in the direction of the southern polar cap.
Where the first and second pictures overlap, there is a twelve-mile-wide dark spot that JPL picture analysts believe is genuine and not a camera smudge—but what it is, they are not sure. The third picture, snapped from 9,500 miles out, is the most interesting one so far. The contrasts are sharper, bringing out the first distinctive features to be seen in the Mariner pictures: some faint suggestion of shallow craters similar to those on the moon, and a long depression that could be a valley.
More pictures are on the way. They may reveal much more of what Mars looks like because they will cover areas generally thought to have a more varied terrain. Unlike the first shots, the later pictures were made in afternoon lighting, and shadows should bring out sharper contrasts. It will be weeks, though, before they are released.