Curiosity

by Rod Pyle

  With the advent of modern rocketry in the twentieth century, these simple ideas became elaborate plans. No less a personage than Wernher von Braun, alleged Nazi and father of the Saturn V rocket that took America to the moon, labored on the problem. In his 1953 book Das Marsprojekt (The Mars Project), von Braun envisioned an armada of ten enormous spacecraft assembled in Earth orbit by reusable space shuttles. This fleet would embark sometime around 1965 for a three-year round-trip, including a yearlong stay on the surface of the planet.

  The elaborate scheme was presented in a simplified form in Collier's magazine and generated a great deal of enthusiasm with the American public. This was further fueled by von Braun's appearances on episodes of Walt Disney's TV program Disneyland, which were of course set in Tomorrowland. The capstone episode for von Braun was titled “Mars and Beyond,” and it seemed that we would be heading off to Mars any day now, preceded by a trip to the moon. It all seemed so simple, though vast and expensive. What was not known at the time was the harsh nature of the interplanetary environment, with astronaut-frying radiation that would accumulate during the long flight, as well as the fact that the Martian atmosphere was later discovered to be too thin to support his designs for winged gliders for landing the explorers. Still, it was a grand vision that stirred the imaginations of millions of Americans.

  Then, in 1965, robots intervened, stealing the limelight away from the rugged human explorers of von Braun's imaginings. The truth about Mars would be far crueler—and bleaker—than anyone could have imagined.

  As a youth I watched the American Apollo program's race to beat the Soviet Union to the moon play out, a contest the United States won handily. There had been a brief moment when it seemed the Russians might be the first to accomplish a manned lunar flyby, but the landing itself was never really in question. NASA's machinery, technology, guidance, and navigation techniques were generally superior.

  After losing the space race to America, the Soviets claimed they were never really reaching for the moon after all, that they intended to pursue the peaceful exploitation of Earth orbit with a space station (a feat they accomplished in 1971 with their Salyut space station, two years before the United States matched the feat with Skylab). It was a significant achievement.

  But there was another, quieter race between the global superpowers. The Soviet Union and the United States had been competing in space since 1957. In 1961, Russia attempted to fly Venera 1 past Venus, but the spacecraft lost contact with Earth after a week. Venera 2 suffered a similar fate, but the die had been cast in robotic exploration. In the same year, the Soviets did successfully orbit the first man in space, and in that case beat the pants off the United States. This rankled. NASA, at that point only three years old, was famously ordered by President Kennedy to land a man on the moon by the end of the decade. They were also more quietly given a mandate to explore the planets. A second, less public space race was born.

  The United States reached Venus in 1962 with the Mariner 2 spacecraft. Along with a strong push to develop and fly robotic craft to reconnoiter the moon for Apollo, NASA ordered JPL to start pressing for Mars and Mercury as well as Venus. Of these, the Martian flights would be the most spectacular. This also threw down the gauntlet at the feet of the Soviets, who had Mars plans of their own. Their first Mars rover would beat Curiosity by forty years…sort of.

  The flights of Mariner 4 past Mars in 1965, Mariners 6 and 7 in 1969 and the orbital mission of Mariner 9 in 1971 were all significant successes. In the same time period, the Russians hurled a number of probes toward Venus with the intention of landing on that hellish planet. From 1966 through 1970, no fewer than five landers failed in various stages of their missions (though Venera 4 did transmit data during its descent before failing). Finally, in 1970, Venera 7 landed on the surface, enduring the 900°F temperature and well over 1,000 psi pressure for twenty-three minutes before succumbing.

  But Mars eluded the Soviets. In the same time frame, roughly 1960 through 1975, fifteen Soviet robots were sent to Mars. This shadow space race spawned a number of US attempts as well: six Mariner probes were sent to the same destination. But the results were spectacularly skewed: the US was four for six. The Soviets? Zero for fifteen. It was an amazing string of almost total failure for the Union of Soviet Socialist Republics (USSR).

  Not so the United States. From its late start and shortly after that string of embarrassing second-place accomplishments, NASA quickly and quietly turned things around with the robotic cold warriors called the Mariners.

  Of these, Mariner 4 merits recounting. It was launched just a few weeks after its twin, Mariner 3, failed due to a malfunction of its launch cover. Mariner 4 launched successfully and raced off to arrive at a point in space that would allow it to miss Mars by a few thousand miles, snapping images as it raced past the planet at interplanetary speeds. That was the hope anyway. With just one successful Venus mission under its belt, NASA could only plan and hope for the best.

  Mariner 4 would succeed brilliantly but would not be kind to the romantics among us.

  By this time, 1965, much was known about Mars. But these investigations had been conducted at the small end of large telescopes—some of which gathered optical light, some of which gathered radio signals. But all were firmly rooted on Earth and limited by that restriction. As previously stated, it was a tough way to observe, and in this era before computer-controlled adaptive optics and the like, it took a still night and a keen astronomer's eye to make much of what one could see. Also as previously mentioned, radio telescopes had the advantage of cutting through this atmospheric mishmash but still suffered from radio “noise,” both from earthly sources and the great cosmos above. It too took skill to separate the wanted from the unwanted.

  While much had been learned about Mars since the days of Galileo, it was nothing compared to what could be gleaned from even a fast flyby of the planet by a robot. But what had been learned by this time, the early 1960s, had already thrown a wet blanket on the followers of Lowell and others of his ilk. It was suspected that Mars had a much thinner atmosphere than predicted at the turn of the century—as little as one-tenth of Earth's, it was thought. There was also pitiful little water indicated by spectroscopic studies. Oxygen was almost nonexistent. What was not known was what might be seen on the surface once Mariner got close. There was a phenomenon that had been studied since the advent of larger optical telescopes in the nineteenth century called “the wave of darkening,” which was a seasonal phenomenon that occurred roughly every two years (one Martian year). Each of these waves appeared to be related to polar ice changes and seemed to indicate that something was spreading from those regions to the equator on Mars. Was it plant life, as many had predicted over the decades? Was it a series of dust storms caused by seasonal changes? Or was it perhaps merely an illusion, as others thought? This query would have to wait for the robots to do their work. One thing did seem certain: the canals, so often observed in the nineteenth century, were far less apparent in the twentieth. It was not good news for Lowell's believers.

  It is worth noting that the optical coating of lenses, that is, the depositing of a thin layer of special elements on lenses to cut down on reflection, did not come into wide use until the twentieth century. This may be what first killed the canals of Lowell and Schiaparelli—it has been postulated that the nineteenth-century astronomers may have actually been mapping the reflections off the eyepiece of the capillaries in their retinas. The antireflective coatings of later years may account for the reduction in observations of canal-like features—we will never know for sure. But Lowell would surely be ashamed if he realized that his vast empire of brilliant Martians was actually just meandering blood channels in his eyeballs.

  A personal note—I was nine years old when Mariner 4 flew past Mars, and I followed the mission carefully (as carefully as a nine-year-old can follow anything). After all, JPL was only about three miles from my house. In fact, I later discovered that my childhood home was within the bla
st radius of Soviet nuclear warheads aimed at both JPL and Caltech—that's kinship. In any case, I felt a sense of connection with the robotic programs being conducted from there. Of course, as a youth steeped in the science-fiction movies and books of the day, I was wedded to Lowell's romantic fantasies as much as anyone had ever been. My father had taken me on a trip to Lowell's observatory in Flagstaff, Arizona, and there I had seen the gigantic (to a nine-year-old) telescope Lowell had used to create his elaborate illustrations of Mars. My primary memory besides the amazement I felt when I saw this wonderful, polished, brass and steel star-cannon was my surprise that the massive wooden dome that housed it rotated on a series of automotive wheels and tires. It seemed an ill fit for the grandeur of the enterprise.

  At the time, Lowell Observatory was in the odd spot of wondering what Mariner might find on Mars, and how it might compare to the vision of its founder. Astronomy had long since moved on from Lowell's Mars, but some, like the readers of the illustrious Ray Bradbury and his 1940s fictions about Mars, were steadfast—it wasn't over until it was over; the fat lady had not sung; and Mariner had not yet flown past the red planet. There was still a chance, no matter how small. But the red sand was flowing through the hourglass, and time was running short.

  On July 14 and 15 of 1965, Mariner 4 made its kamikaze dash past Mars. The magnetometers searched for a magnetic field (and found little), the radiation detectors recorded their findings, and the TV camera snapped 22 and 1/2 grainy, low-resolution images of the planet as it hurtled by. Data were recorded to an onboard tape recorder for later playback, since transmission rates this early in the digital-imaging game were dreadfully slow.

  Back at JPL in Pasadena, the numeric data were coming down, but it would take much longer to photographically print the ghostly black-and-white images. Impatient scientists took some of the data printouts, which were, after all, numeric indications of gray values, and with a set of colored crayons made something like a paint-by-the-numbers kit and created the first close-up images of Mars.

  A small historical aside: when the guys in the white shirts and skinny ties wanted to color-in the printout, they had nothing but gray pencils at the lab, so they ran down to a local Pasadena art store. The snotty clerks there (they were still that way when I went to art school in the 1980s) told them that they did not carry actual crayons—those were for little kids. They did, however, carry greasy pastel paint sticks. The engineers had their choice of yellow-orange flesh tones, or blue and green. They opted for flesh tones—otherwise, our first color images of Mars might have looked more like a blob of algae. That resulting hasty drawing, in all its fleshy grandeur, still hangs on a wall at JPL today.

  Then the actual pictures came out from the darkrooms. The aforementioned scientists gathered ’round, passing the prints from person to person while they were still dripping wet. They were dim, fuzzy, and monochrome…but to them, beautiful. Here was proof at last that Mars was not home to canals, forests, or oceans, but that it was indeed a dry, apparently lifeless desert. The images showed craters not unlike those seen on the moon, and little else. The romantics had their images of a fecund, inhabited Mars shattered in an afternoon. The cities, the oceans, the planet-girdling canals built to save a dying culture vaporized. It was a bad day to be a romantic, and I remember it with a bitter taste.

  Fig. 4.1. FIRST FROM MARS: This is the first image transmitted by Mariner 4 in its 1965 dash past Mars. The 22 1/2 images it sent back were low-resolution, indistinct…and enough to convince the scientists that Mars was as dead as the moon. Image from NASA/JPL-Caltech.

  Four more Mariners would be shot into space for a rendezvous with the God of War. Mariners 6 and 7 were also flybys, reproducing the mission of Mariner 4 with greater precision and passing far closer to the planet (for those of you who are counting, Mariner 5 went to Venus). But it was the final Mariner effort that really stunned the planetary-science world.

  In a replay of the Mariner 3 failure, Mariner 8 aborted its Mars mission when the rocket booster failed and exploded. Mariner 9, which had been programmed with slightly different objectives than its twin, would now have to do the work for both, mapping the red planet from its equator to the poles.

  Mariner 9 reached orbit without undue drama in November 1971 and sped off to Mars. But this was a Mariner with a difference: it was far larger and heavier, and it carried a quantity of rocket fuel that would allow it to brake into Martian orbit. On November 14, 1971, it did just that and entered orbit around Mars…right in time for a planet-girdling dust storm.

  When the storm abated a month later, JPL turned the cameras back on and started imaging the planet from close up. First, three massive circles appeared above the settling dust—and the planetary scientists realized that they were looking at the largest volcanoes ever seen, on any planet. Then, as the clouds continued to clear, more and more features swam into view. Within a few months, the machine had mapped a goodly portion of the planet, and what the scientists saw stunned them.

  The dead, arid Mars suggested by previous flights was now visible in stunning resolution (for the time), and a whole new story began to form. There were what looked like ancient river deltas, alluvial fans, canyons, fissures, and other features whose origin clearly involved sculpting by water, and lots of it. Lowell's romantic (and apparently once-wet) Mars recovered by one tiny increment, and we now saw it as a complex and still-active world.

  Then the Viking program, a mission as audacious as it was evolutionary, took final form. In the making since the early 1960s, these twin massive probes—each with an orbiter and lander—would head off to a rendezvous with Mars in 1976. The orbiters would continue the work of the Mariners: map the surface, search for a magnetic field, and in general explore the regions above the planet. But the landers would be something brand-new and amazing.

  It should be noted here that the United States was not technically the first nation to land on Mars. The Soviet Union had enjoyed a string of early successes (after a fashion) with the exploration of Venus. That planet—both closer and easier to navigate to from Earth—was to become to domain of Mother Russia for quite some time. The USSR had an early advantage of larger rockets than the United States, and their probes to other worlds reflected this. Huge, bulbous, and bizarre looking, these spacecraft were heavy and unwieldy, but the Soviets had lifting power to spare, so it was a nonissue. As it turns out, the bulkiness of the Russian spacecraft had a simple origin: their electronics were not up to the task of operating in a hard vacuum (as the US spacecraft had done since the beginning), so the Russians pressurized them. In short, they created the equivalent of small, pressurized space capsules to house their electronics and protect them against the harshness of space. As a result, the machines looked as much like a disease as they did like planetary probes, but they worked—sometimes.

  So the Soviet Union had flown a chain of tough spacecraft to Venus with some success. But when they sent missions off to Mars (which they did with staggering regularity) the game changed. Mars is hard, as more than one JPL employee has stated with chagrin, and has remained beyond the scope of Soviet (and later Russian Federation) technology for decades. But when one of those doomed Russian spacecraft, Mars 3, joined Mariner 9 in Martian orbit, five years before the Vikings arrived at the red planet, a Soviet lander detached from the orbiter and managed to set down on Mars. Once on the surface, the machine began to take a picture to celebrate the triumph of the Worker's Paradise over the decadent West—and then it died, having transmitted just seventy lines of video gibberish. It survived there for a scant fifteen seconds. But the Soviet Union did not give up easily (ask a German soldier from World War II) and continued to send a string of spacecraft to Mars for decades. None have made it to date.

  Of interest to the American Mars rover planners, the first rover on Mars was not actually Pathfinder's Sojourner, as is so often stated. The Mars 3 lander had a tiny rover on board, which was truly revolutionary for its time. It looked like a maimed Hoover vacuum cleaner
without the handle, was attached to the lander with a roughly forty-five-foot cable, and was designed to gimp along on two skids that would lift, move forward, and nudge the rover along with them. It was actually an ingenious system and, while limited in scientific scope, was well ahead of its time. Unfortunately, it died along with the Mars 3 lander.

  The United States, meanwhile, had been spending copious amounts of money designing and building the Viking spacecraft, especially the landers. Not content with making better maps from orbit, and not satisfied with landing there merely to perform basic surface analysis, Viking's designers upped the ante substantially—they wanted to look for life. The results of this life-science orientation would set the stage for every Mars surface mission to come, and would ultimately steer mission decisions for Curiosity.

  Fig. 4.2. BRILLIANT BUT FLAWED: The USSR's Mars 3 mission was comprised of an orbiter, a lander, and a tiny rover sent to Mars in 1971. The lander is seen here. It could have been a spectacular all-in-one mission, but design flaws and bad luck resulted in useless pictures of a dust storm–covered planet and a dead lander. Image from NASA.

  The Viking program would enjoy a budget that later JPL program managers could only fantasize about. While the mission was flown six years after the semiofficial end of the space race, it was proposed, designed, and built at the height of that contest for technological domination. The $1 billion budget would equate to something like $7 billion today…a truly vast sum by current standards and one we are unlikely to see again for a single planetary program (perhaps if they found a pyramid on Mars…). But during the Apollo years, it was just a trickle from the roughly 5 percent of the US budget spent on the overall space program.