Mariner 9 as Catalyst

In May 1971 NASA launched Mariners 8 and 9. Mariner 8 failed at launch, but Mariner 9 succeeded in moving toward Mars. NASA was fortunate to have had two Mariner launches in 1971. When the Mars program was revived after the Voyager demise, Newell, as NASA associate administrator, argued for spending extra money for a second Mariner. Webb had gone along with this view, as had Paine when he became NASA Administrator.38 Shortly after the Mariner launch, the Soviet Union sent two probes, which it called Mars 2 and 3, toward the Red Planet.39 NASA determined that the USSR spacecraft were much heavier than U. S. probes. That could only mean that they not only were orbiters (as were Mariners 8 and 9) but carried landers, and possibly even biological detection equipment. NASA sought to establish contact with the Soviets to see if there could be some cooperation in the respective endeavors, but the Soviet Union

remained secretive about the objectives of its Mars program. The goal of Mari­ner 9 was well known—to orbit Mars and take photos of as much of the planet as possible. The aim was to scout possible landing sites for Viking—places both safe and promising potential habitability. But if the Soviets succeeded in landing with their probes, they would leapfrog Viking by more than four years.

By November, it was clear that the United States would reach Mars first with Mariner 9. There was considerable speculation and debate among scientists about what Mariner 9 would see. A host of scientists associated with the Mariner program gathered at JPL’s mission control center in Pasadena, California, as the probe approached. Sagan, optimistic as ever, was a principal investigator on the project and eagerly awaited.

On November 12, the evening before Mariner was scheduled to go into orbit, a remarkable panel discussion was held at Caltech, entitled “Mars and the Mind of Man.” There were numerous media representatives there to hear the discus­sion and also interview Sagan and other scientists. The panel was chaired by New York Times science editor Walter Sullivan. In addition to Sagan, the key planetary scientist on the panel was Murray of Caltech. Science fiction writers Arthur Clarke and Ray Bradbury also were on the panel. Both had written of life on Mars.

Sagan and Murray had become prominent antagonists on the Mars life issue. Sagan pointed out that scientists (like Murray) had been too quick to reject the possibility of life-forms on Mars. “There have been excesses in both directions,” argued Sagan. “And one direction was the premature conclusion that there isn’t life on Mars.” While data were incomplete, said Sagan, all the necessary ele­ments of photosynthesis—the life process of plants—existed on Mars: water, sunlight, and carbon dioxide. The ice caps, which advanced and receded with the change of seasons, could leave pools of water that could contain life forms.

The science fiction writers were in Sagan’s corner, but Murray dismissed such views. He charged that even good scientists (like Sagan) were deluding themselves. Life on Mars was “wishful thinking.” He attributed such thinking, which made scientists misinterpret data, to a “deep-seated emotional desire” on the part of humanity to find “another Earth” somewhere. Mars was not that Earth.

Privately, Sagan and Murray would debate at length. Andrew Chaikin has written that Sagan’s comments would “make Murray want to roll his eyes.” Sagan was three years Murray’s junior, but they appeared to be on “opposite sides of a generational divide.” They respected one another and would eventu­

ally become friends. But with Mariner 9 in the offing, they simply disagreed strongly. Sagan privately once snapped at Murray, “You at Caltech live on the side of pessimism.” Murray did not respond, but thought, “And you at Cornell, Carl, live on the side of optimism.” Murray, on the panel, told Sagan and the others he accused of “wishful thinking” that Mariner would settle the issue, and he expected it to provide “the observational stick” to force Sagan and his allies to recognize reality.40 For Murray, the absence of evidence proved his point. But Sagan came from a different perspective. As he later wrote, “The absence of evidence is not evidence of evidence.”41

Everyone would have to wait a while, however. The next day, Mariner 9 suc­cessfully moved into Mars orbit. Going into Mars orbit was itself a great first. But a huge dust storm swirled about Mars, obscuring almost totally images of the planet. NASA decided to simply let Mariner 9 go around and around Mars and wait out the storm.

Meanwhile, later in November, the two Soviet probes joined Mariner 9 in circling the Red Planet. The USSR spacecraft did not have the fuel to match that of Mariner 9 and thus wait a lengthy time to see Mars. They soon released their landers. Only one made it successfully to the Mars surface. This landing was indeed a significant first. However, something went wrong and after 20 seconds the probe’s communications ceased. It transmitted no images of Mars.42

The next round of Mars exploration thus depended on Mariner 9, once the waiting was over. In late December 1971 the dust cloud gradually cleared. Sci­entists at JPL saw four dark spots in the northern hemisphere that peered up at them. They thought them to be big craters. But eventually, as views improved, it became obvious that these dark spots were mountains, and in fact gigantic volcanoes. The scientists’ reaction at the time was a collective “Oh, my God!”43 The largest of these volcanoes had to be 15 miles high, three times the height of Mount Everest. The crater at its summit was the size of Rhode Island; its base that ofArizona. Soon they saw an enormous rift valley that extended at the Mars equator region 2,500 miles, as well as a canyon system that was 75 miles wide and 4 miles deep. Moreover, they eventually saw what seemed like channels (the “canals” of Martian lore) that might have been carved by running water.44 Mi­chael Carr, a young scientist on loan from the U. S. Geological Survey, recalled his sheer excitement when he saw the images. Mars “was a wonderland. It had unfolded before us.”45

Humanity’s image of Mars was suddenly transformed. The science fiction writers in the pre-space age had painted a Mars that was like Earth. The Mari-

ners of the 1960s had made Mars into a replica of the Moon. Mariner 9 revealed a unique planet. For the first time, earthlings saw the real Mars, and it was spectacularly different from Earth or the Moon. Murray admitted he was totally surprised. As a geologist as well as planetary scientist, he could detect signs of an extremely active planet in the past. He had himself “been the victim of his own preconceptions about Mars, even as he’d been warning his colleagues and the public not to fall prey to their own.”46 While Murray still did not believe there was evidence of life on Mars, he was now open to the possibility of being yet surprised again. As for Sagan and the exobiology community, they became more convinced that if they looked in the right places in the right way they could find life. For skeptics and optimists alike, the importance of Viking enlarged immensely.

Mariner 9 was a strong catalyst for Viking. But Viking would not succeed if NASA did not survive.