Curiosity Read online

  Events are occurring rapidly. Data from multiple onboard radars are guiding the machine to a landing inside Gale Crater, and within that into a landing zone called a “landing ellipse” due to the shape. It is just over five miles in width, and its long axis is twelve miles. It is the most ambitiously accurate landing attempt yet, and from what the folks back home can see, as smooth as any to date. The rocket pack/descent stage and its associated winching mechanism, collectively dubbed “sky crane,” is working perfectly. In the final phase of what looks like a landing cycle designed by Rube Goldberg, or possibly Wile E. Coyote, the descent stage slows to a walking pace and sky crane begins to winch the Curiosity rover down via four cords, each about sixty feet long. It is by far the most complex interplanetary robotic undertaking in history.

  Manning is at one of the rearward consoles, not quite with the old guys in the back but not with the youngsters at the front either. He's watching the system he led his team to create—not just sky crane but the whole landing system—and probably also thinking about the last-minute fixes he applied to Curiosity while it was already bolted atop the rocket, ready to launch. It was a close thing.

  Al Chen is on the console as the operations lead for this critical phase of the mission and also the voice of MSL tonight. He is in his thirties, is married with three kids, and is normally a pretty unassuming guy. MSL has thrust him into the limelight, and his announcements come over the speakers in hushed, almost-unbelieving tones: “Sky crane deploying.” It's JPL shorthand for “Holy s—! This damn thing works!” A collectively held breath releases and some scattered cheering issues forth, followed by applause. Then, a few moments later: “Touchdown confirmed—we're safe on Mars!”

  The room goes nuts as controllers, scientists, engineers, and other associated JPL’ers erupt in heartfelt cheers. In a nearby building, inside the press room, normally stoic and hardened reporters from the major TV networks, newspapers, and periodicals just lose it. It is true pandemonium. Curiosity has arrived…and done so to perfection.

  On Mars, MSL's rocket pack, comprising the engines and the navigational unit that brought the rover to the surface, has long since detached and flown off to crash a few miles distant. After a muffled thump, silence returned to Mars.

  It will later be concluded that the rover alighted about 1.5 miles from point zero, well within the landing ellipse. It's a true pinpoint landing, as close to Mount Sharp, their primary objective, as anyone dared to hope.

  Fig. 2.1. THE VOICE OF EDL: Al Chen on the console shortly before touchdown, narrating the entry, descent, and landing phases like a play-by-play. Image from NASA/JPL-Caltech.

  Once the machine is secured, a jubilant EDL team bursts forth from mission control, heading to the press room (in more normal times, JPL's auditorium), wearing matching powder-blue polo shirts and chanting “Eee-Dee-El! Eee-Dee-El!” in triumph. It is a rare moment of collective joy and outright, raw emotion for these normally reserved people as they literally dance across the university-like quad. And it is well deserved.

  Grotzinger smiles broadly, hugs a few people, pumps even more hands, and prepares for the press conference soon to follow. Rob Manning is mobbed by well-wishers, smiles like the punch-drunk engineer he is (he has been at this for eight intense years and has not slept much for almost thirty-five hours), and heads off to a series of interviews. Joy and Vandi hug coworkers and then begin to think ahead. Unlike Grotzinger, they do not have the camera lights and questions of a press conference to distract their attention from the challenges that lie before them. Both return to thinking about the larger mission—the upcoming milestones needed to ensure that the rover can accomplish its primary objectives.

  Bobak Ferdowsi takes a moment to check his smartphone and discovers that in the past few hours, he has become an Internet meme and instant sensation. But there is not time for that now; he has people to congratulate and a rendezvous with a pillow. Ashwin feels the glow begin to fade a bit. He is responsible for coordinating the moment-to-moment science activities of the mission, a massive job, and tomorrow things will get very busy regardless of how much—or how little—sleep he manages to get. Nonetheless, he will remember the landing as one of the high points of his life.

  Hundreds of others on-lab, and hundreds more offsite, pop champagne corks and toast success tonight. They enjoy the moment, as well they should, for tomorrow engineers, scientists, and managers begin a multimonth grind known as Mars Time—their days will match Martian days, known as “sols,” which add forty minutes to each twenty-four-hour Earth day. The world will soon become a surreal, time-shifted place to the bleary-eyed participants in Curiosity's mission. But tonight is for celebration.

  On Mars, the dust has settled around the unmoving rover. A few clicks and whirs can be heard from the inside as the Hazcams pop open lens coverings and begin imaging the immediate surroundings. Other mechanisms restrained for landing free themselves, and heating systems power on for the cold Martian night ahead.

  Curiosity has arrived, and the greatest adventure Mars has known is about to begin.

  Exploring Mars has been a passion of earthbound scientists for centuries. Few thought of actually going there until the mid-1800s, but notions of Mars as a planet where beings might exist date back nearly two hundred years earlier. Christiaan Huygens, a Dutch astronomer and cosmologist, published a book in 1698 that speculated about life on the red planet. This idea bloomed in the 1800s, but it would be much later that the idea of exploration of the planet with humans was taken seriously. The idea of using machines to do so came later still. Many early visions harkened back to the golden age of earthly exploration, which was not conducted by robotic machines—there weren't any to do so yet. These voyages were accomplished by men in square-rigged ships that traveled to distant and forbidding places to plant the flag of their nations in faraway lands (and often cause disease and destruction to rampage through the native inhabitants). Surely, the thought went, the exploration of Mars would be accomplished in a similar fashion—by men (probably military) in rocket ships.

  While many over the centuries thought of traveling to other worlds, it was not until Mars was understood as a planet—that is, a place—that these notions gained any sophistication. But even very early observers with scientific grounding began to notice things about Mars that were telling. In the fourth century BCE, Aristotle noted that Mars was occulted by the moon—Mars clearly passed behind it. This led him to the conclusion that Mars was farther away from Earth than the moon was. While this may seem painfully obvious to us today, at the time little was known about anything in the night sky; certainly Mars had not yet been identified as a world.

  The earliest observations of Mars centered on its color. Few objects in the night sky exhibited any hues other than white, and none were as ruddy as Mars. So it is not surprising that the planet became intimately identified with all things violent—war, famine, and death. The various mythic figures that Mars became associated with were murderous at worst and portended a bad day at best. It was the Hannibal Lecter of celestial bodies.

  Ancient Babylon, Egypt, and China all had deities associated with Mars. To the Babylonians, Mars was associated with Nergal, a deity of fire and destruction. To the Egyptians, Mars was Horus the Red, associated at first with the harvest, but later with violence. China and other Asian cultures saw the planet as representing fire and all its unpleasant associations, and eventually with mayhem. You didn't want Mars (or Nergal, Horus, or even the combustible Asian version) dating your daughter.

  The Greeks also worshipped Mars as a god, named Ares, who carried with him the usual unfortunate associations. Though he was the son of Zeus, king of the gods, and his wife Hera, who was beautiful and wise, Ares was a wayward scoundrel and simply could not live up to his parent's accomplishments without getting into trouble. Perhaps the fact that Hera was also Zeus's sister may have been a factor—a troubled gene pool indeed.

  The Romans had a similar interpretation of the god they renamed Mars.
While they imported his virtues—or lack of them—from the Greeks, in Rome the red planet's penchant for violence was considered a big plus. Since the empire would conquer and rule by force, paying homage to Mars's psychotic tendencies made a certain amount of sense. The one thing the Roman Mars did have over his predecessors was a measure of intelligence—in many previous iterations, he was downright doltish. If the Romans made him a violent and warlike being, they also made him a smarter one. He went from being Steinbeck's Lennie to TV's Dexter in one sweeping cultural iteration.

  Then Ptolemy, a Greek living in ancient Alexandria, came along in the second century CE and (surely with the best of intentions) created a model for the solar system that brought some apparent order to the chaos seen overhead, but also gummed up Western astronomy for well over a millennium. In his universe, Earth was at the center of all things, and the lights observed in the sky moved around it. These other bodies were affixed to spheres—unimaginably huge, crystalline, transparent ones—that rotated, imparting the motions observed. The obvious planets, those observable by the naked eye (Mercury, Venus, Mars, Jupiter, and Saturn), each had a crystal sphere of their own in logical order. The moon's was closest to Earth, the sun fell between Venus and Mars, and the final sphere was that upon which the stars were mounted. This system, logical from a contemporary observer's viewpoint, was to remain fixed in place (just as Earth was, at dead center) for about 1,200 years. It was one of science's longest-held misconceptions, but at least it was an attempt at science. Despite this valiant effort at understanding the solar system, the broader culture that surrounded Ptolemy continued to see gods in the heavens.

  Mars continued to be the scourge of the cosmic playground through medieval times, and not until 1543 did the red planet really become a what rather than a whom. Nicolaus Copernicus, a brilliant Polish astronomer, was finally able to build a mathematical model that supported a heliocentric system, that is, one with the sun at the center of the solar system (in fact, the sun was the center of the entire universe so far as he was concerned, but that inconvenience was cleared up much later). Then, almost a half century later, Johannes Kepler, a German scientist who worked out the laws of planetary motion, further developed the mathematical certainty of a sun-centered system.

  About the same time, Galileo Galilei began looking the planets through his telescope, observing, among other things, the distinct phases of Venus. He was also able to see the planets as objects, not just as points of light, and their massiveness and motions under a heliocentric model made even more sense. He couched his opinions somewhat, though, as he had already endured enough torment at the hands of the Renaissance church to make him gun-shy. Speaking openly of his ideas turned out to be a recipe for papal investigation and, ultimately, a lifetime of house arrest. Sometimes it sucks to be too far ahead of your time.

  It was not until the 1800s that Mars truly came into its own as a planet, apparently similar to Earth, in the minds of astronomers. While many were using telescopes at this time to observe the planets, notable among them was Giovanni Schiaparelli. During Mars's closest approach to Earth in 1877 (when the two planets’ orbits bring them closest together, an event called “opposition”), he began a series of extensive observations that resulted in one of the first true maps of Mars. Schiaparelli invented a vast network of continents and seas for the red planet, further adding to its Earth-like mystique. Mars was continuing on its long journey to being a world, a place, that could be explored and—possibly—inhabited.

  Among Schiaparelli's unintended “gifts” to Western science was the misinterpretation of his observation of linear features on Mars that he called canali. While in his native Italian this merely describes a channel (natural or not), to the English-speaking ear this sounds like “canal,” and in a profound case of mistaken identity, a great controversy began.

  Fig. 3.1. PLANETA MARTIS: Schiaparelli's Mars map of 1877 demonstrated far more detail than he was able to see through the telescope. Many of the lines seen here did not exist, and were either figments of his imagination or the possible result of eyestrain. Regardless, these charts had a profound impact on popular thinking about Mars and strengthened the tradition of naming features in Latin. Image from NASA.

  This misinterpretation was picked up and vastly amplified by an American amateur astronomer named Percival Lowell. Born of a wealthy Boston family with a fortune made in the textile business, Lowell spent years in Asia making a mark as a chronicler of Japanese culture before taking up astronomy seriously (he already had a degree in mathematics from Harvard). Once bitten by the celestial bug, however, he was unstoppable. He moved to the Arizona territory in 1894 and built an observatory in Flagstaff with the stated aim of observing Mars. Lowell commissioned one of the larger refracting telescopes of the time, an instrument twenty-four inches in diameter, to facilitate his Martian observations.

  It's interesting to note that Schiaparelli and Lowell were somewhat contemporary to one another, with their respective peak activities being offset by about twenty years. When confronted with Lowell's interpretations of his work, initially Schiaparelli was somewhat miffed, but over time he softened and moved from denial to ambivalence, then even to a certain level of enthusiasm, about the idea of artificially created canals on Mars. Even then, people seemed to know the value of good PR. Lowell was the P. T. Barnum of Mars, and if you can't beat ’em…

  Lowell took to his new life's purpose with relish. Over the next fifteen years, he spent countless nights in his cold observatory, observing and sketching Mars. Lowell also saw the elusive canals but perceived of them differently than did Schiaparelli. He charted these illusory features in much greater detail, numbering them and striving to discern some logical order to their design and placement. From these extensive and painstaking (and largely imaginary) observations, he began to develop his own theories about Mars and what—or whom—might exist there. Perhaps most profoundly, rather than limiting his ideas to scientific circles (where he met with opposition to his unique notions), he published a series of popular books between 1895 and 1908 that struck a chord with the general public.

  These widely read books built a public case for intelligent life on Mars. Going far beyond mere observation and charting of the planet, Lowell imagined a vast civilization with a form of planetary government (after all, the rulers would need to have global reach to build such a vast network of canals). This technologically brilliant Martian empire was working against the clock to save their dying world as the water vanished. Mars was much older than Earth, he reasoned, and was thus farther along in its planetary evolution. It was cooling and was water-starved, and the Martians had built the vast network of canals, complete with pumping stations, locks, and other manipulations, to bring water from the poles of the planet to its parched temperate regions. It was an elaborate mental invention, and the romance of these ideas was to last for a half century in the public mind. Lowell's ideas about how Mars lost water were not really wrong, they were just off by about 3.5 billion years. The rest, engaging though it might be, was just so much mental popcorn.

  While it is easy to dismiss Lowell's fanciful ideas today, reading his books (not a trivial undertaking) does impress one with the (admittedly misplaced) rigor of his thinking. If one starts off by accepting the idea that his Martians might actually exist, he builds a convincing case, using whatever scientific ideas were supportive to his arguments. While this is not a true implementation of the “scientific method,” it was an attempt at building a logical view of another culture that held some allure.

  Although few discuss it today, while Mars was wiling away the early twentieth century as a planet inhabited by parched, clever engineers, Venus was thought to be a sunny, humid jungle world. Little was known about the planet, and virtually nothing could be observed beneath its opaque cloud cover. Well into the 1950s, popular culture (aided by the likes of Edgar Rice Burroughs, who had his way with both Mars and Venus), Venus was the jungle world, with riotous plant growth and steaming swamps
. The truth was even more shocking than it would be with Mars, as Venus was ultimately unveiled as a hellishly hot, sterile, acidic nightmare.

  During the first half of the twentieth century, other scientists spent years observing Mars via the telescope, often striving to disprove Lowell's assertions. Using spectroscopes as their primary weapon, various observers were able to discern that there was far less water in the atmosphere than Lowell had theorized, and that the air was much thinner than appropriate for his Martian civilization. Lowell's romantic world was beginning to slip away.

  This work was, however, restricted to the evidence of the telescopic eyepiece and other earthbound methodologies of observing Mars. Under optimal conditions, with a large, well-placed telescope, and even during its closest approach, the best image of the red planet is still subject to the vagaries of what astronomers call “seeing.” Earth is covered in a blanket of air, turbulent and fickle, and air is dense enough to distort light. So even on the best of nights, the small, dim, red image of Mars swims in and out of focus, bending and flexing at the whims of the atmosphere. Profound or accurate observations of the Martian surface are difficult at best. The use of the spectroscope, a prismatic device that splits the light from a planet or star into its constituent gasses and elements, strove to overcome this limitation but was able to supply only a limited range of answers. Later, radio telescopes, unaffected by the optical properties of the atmosphere, were utilized to explore Mars but were also limited in what they could “see” on a planet and had other issues with Earth-based interference and background noise from space. In short, to really understand Mars, we would have to go there.

  This idea of traversing the great blackness between Earth and Mars had appealed to many over the years. Fiction treated it in various ways: In the worlds of Edgar Rice Burroughs, writer of the John Carter books, all you needed to do was fall asleep in the back of an enchanted cave in the Wild West and * poof * you awoke on Mars. Later on, the brilliant Russian Konstantin Tsiolkovsky and Germans like Hermann Oberth speculated on the use of rockets to carry people into space and perhaps even onto other planets. They were widely dismissed as cloudy-minded visionaries at best, crackpots at worst.