Curiosity

by Rod Pyle

  That does sound like a blast. I asked others to see how their experiences compared.

  Lauren DeFlores had worked on the MER mission, then the Mars Phoenix lander in 2008, so she was by now an old hand at Mars Time. But Curiosity threw her a new challenge—or perhaps it's more precise to say that the mission's timing did. She was an integration engineer for the ChemCam and DAN instruments, but she was also soon to have her third child.

  “Mars Time on MSL, the first ninety sols, was also my first trimester of pregnancy. I actually think it worked out really well because no one could tell how tired I was because everyone was tired.” She smiled. “I think one of the greatest things is that our project management does do is every time there's some sort of large event they think of our families first. That provides unconditional support, dealing with people who are working with ungodly hours. So during that whole ninety sols I was working probably ten to twelve hours a day, or per sol, only sleeping for a few hours, and coming back for another shift. It was pretty rough in the first months, and then it got a little better. I was pregnant, but my husband took care of the kids.”

  Good man, he. I began to think that this Mars Time thing was pretty interesting, so I thought, why not try it? As a writer, I work bizarre hours anyway, so I gave it a shot for a week. At first I did not notice much. And since my hours are normally all over the place, it was not a big deal. So I extended it a few days…and then it begins to really catch up with me. By day 6, my cat was looking like me as if to say, “What the heck are you doing in my part of the house at this hour?” and my son simply slept through it. I gave up. Somehow, without the unifying experience of being on a mission, it was just not the same writing about it and being sleep deprived.

  While my son may not have been interested, participants in the mission with younger children found it sometimes made quite an impact. David Oh, a flight director for the mission whom I spoke with as Mars Time came to a close, took an unusual step. “For the first month after landing, my whole family joined me on Mars Time. And we jumped a time zone per day, every day, for thirty days, going all the way around the clock. We got to explore Mars at JPL and Los Angeles at night. It was a great adventure for my whole family.” His kids seemed grateful that they found an International House of Pancakes that was open twenty-four hours.

  At the end of the three months, shifts adjusted to normal working hours, and many nonlocal team members went home, adding jet lag to the wacko schedule change. For some it was three hours to the East Coast, to others it was ten or twenty as they headed off to Europe or Asia. But to a person they agreed: Mars Time, grueling though it is, is a wonderful and unifying experience. Watchmaker Garo Anserlian would surely agree. After a surge during the early days of Curiosity, he still sells the occasional Mars watch to anyone willing to pony up the few hundred dollars it costs to make one. When I have a few hundred extra dollars, I just may treat myself to one.

  Exploring Mars is a team effort. From a human-resources point of view, it has been such since the 1960s. Prior to that time, Mars was a telescopic object. As we know, astronomers like Schiaparelli and Lowell spent hundreds of hours at the eyepiece, drawing what they saw. This was by its very nature a solo or small-group endeavor.

  When NASA and the Soviet Union's space-exploration efforts got underway in the late 1950s, large teams were needed to accomplish the gargantuan tasks placed before them. By the time of the United States’ Mariner missions to Mars, small groups of senior scientists worked with larger groups of subordinates—both science people and engineers—to accomplish these large projects.

  Today, partnerships surrounding Mars have taken new forms. The intricate operational ballet between the rovers on the surface, the orbiters circling the planet, and even Earth-based observations of Mars, require great precision in planning and execution to be successful. These overlapping data streams, when properly coordinated, have provided ever more detailed and dense sets of information about Mars—its surface, atmosphere, geological composition and characteristics, radiation environment, and much more. Without this suite of robotic explorers and people working in concert, missions like MSL would not be possible.

  In the 1990s, in the same time frame as Pathfinder, came the largest advance in orbital imaging in twenty years, the Mars Global Surveyor. This is the mission that set Mike Malin and Ken Edgett onto the path toward realizing that there had been sedimentation processes taking place on Mars. It was the first real jump in understanding the Martian surface since the Viking orbiters mapped the planet in the 1970s, which in turn set the stage for the MER and MSL missions. And, while it was generally accepted since the early 1970s that water must have had some role in shaping the tortured landscape the orbiters saw below them, the MGS mission was the first time the scientists began to understand the true nature of, and role of, water in the grand story of Mars.

  Fig. 19.1. EYES ON MARS: The Mars Global Surveyor spacecraft arrived at Mars in 1997 and operated for nearly a decade. It provided the first high-resolution look at Mars and the first orbital images since Viking in the 1970s. The tube at the bottom of the spacecraft is not a rocket, it is Mike Malin's camera. Image from NASA/JPL-Caltech.

  Then the current generation of orbiters were sent out to Mars—the Mars Odyssey orbiter in 2001 and the Mars Reconnaissance Orbiter in 2006. Both were eventually tasked as relay stations for the MER and MSL rovers, handling the retransmission of the copious data that comes back from the ground-based machines. It has been a huge advantage over the line-of-sight, ground-based messages that Pathfinder was restricted to, opening up the bandwidth tremendously. And as we have seen, bandwidth is a huge enabler of—or limitation to—science performed on the surface of Mars.

  Also working above Mars is the European Space Agency's Mars Express (ME) orbiter, which had provided its own trove of visual and other enticements about Mars starting in 2004. One key observation of ME was the apparent existence of measureable amounts of methane in the Martian atmosphere, which can be an indication of biological activity. Since methane does not last long in the Martian air, the reasoning was that it must be continually replenished to be observable. Curiosity has tried to sniff for methane on a number of occasions since touchdown but has failed to detect any, so the jury is out on this one…it might be that the ME indications were erroneous, or perhaps that there is some source of the methane that has nothing to do with processes taking place in and around Gale Crater where Curiosity's measurements were taken. It's nice to imagine a huge subterranean grotto filled with Mars microbes—or Mars cows, six-legged giraffes, or something—generating the gas somewhere near the poles where it would be harder to detect. But that's just my own wishful thinking. I'll always be a bit of a Lowellian optimist. I love science and adore the Mars exploration program, but it would have been keen (to use the vernacular of the day) if Mariner 4 had spotted some canals and a few oceans or forests. Or a herd of a thousand eight-legged thoats (Edgar Rice Burroughs's imaginary Martian steed), moving in unison. But once again, I digress. Back to reality.

  Before the orbiters would give a helping hand with rover data, they would first assist in defining a place to land. By the time the MER mission plans were being finalized, with guidance from Pathfinder and the Mars Global Surveyor data, water was becoming the primary focus—some might say obsession—of the Mars program. There is lots of other great stuff to study, but water-based processes provide tremendous information on the weathering, geological transformation, and landscaping of Mars, and of course is critical to life as we understand it.

  Central to the observation of watery processes on Mars is how it has affected the terrain, exactly what hand it had in the evolution of the Martian environment, and, hopefully, an understanding of when those processes occurred. We've already learned how Mike Malin's observations and hypotheses about water—as seen from orbit—affected some of the landing-site candidates for Curiosity's mission. It's also worth understanding how the orbiters assist in such research. And who better to tell us th
an Ken Edgett—Mike Malin's trusted associate, the man who spent the better part of a decade working ten- to fourteen-hour days looking at well over a quarter million (yes, over 250,000) images of Mars taken from orbit, and the same guy who co-led our grueling trip to Death Valley.

  Edgett is a consummate space scientist and geologist, which is to say that he lives the science. In his spare time—what little there is—he writes children's books about science as well as adult-level science fiction, both of which have been published. Prior to joining Malin Space Science Systems (MSSS), he developed and led a science-education program for kids called Mars K–12 at Arizona State University, where he received his doctorate. He has also worked on children's science television programs, and much more. If anyone is committed to bringing science to young people, this guy is. You can feel his passion for Mars. He practically crackles with excitement, and he is one of the few scientists of his stature whom I have met who will willingly allow emotion to color his expression; not in a gooey, join-hands-and-sing-Kumbayah sort of way, but in confessing that remembering certain moments, like when he realized the true nature of a site he was researching on Mars, or a moment of discovery with MER or MSL, choked him up and still can. Hell, some of those same moments choked me up and I had no involvement in the program. Had I been in his shoes, directly responsible for some of these discoveries, I probably would have fainted dead away.

  I'm going to let him tell his story because at its best, science is the unraveling of a grand mystery, and who doesn't love a good mystery? What is important is how it is told. I spoke to Edgett from his office at MSSS. We began with his work on the Mars Global Surveyor mission, for which MSSS built the high-resolution camera.

  “Every day, starting in 1998, I was in here staring at maps of Mars, looking at where the spacecraft's orbit would go and try to decide what to take pictures of, along with Mike and his team. But I did a lot of it. As we gathered this data, we started to look at what are the most important things that we were finding. There was just so much to discuss. You're peeling the skin off of the cream that rises to the top. There was so much good stuff, we didn't even get to do the cream, so to speak!” This was when I began to understand Ken's passion for Mars. You could hear it in his voice, the way some people talk about their most cherished memories. He then spoke of some of the same pivotal scientific papers (the ones Grotzinger had mentioned to me) as being critical to understanding sedimentation on Mars and being responsible for revising the process of choosing landing sites. “One of the important papers was in 2000…what we both [he and Malin] thought of as the most important from that whole [MGS camera] experiment was the sedimentary-rock observations. Before we did that work in 2000, when people talked about Mars they did not put the words sedimentary and rocks together in the same phrase or the same sentence. It just wasn't something that people were thinking about.

  Fig. 19.2. KEN EDGETT PONDERS: Ken Edgett listens to a question during a press conference at JPL. His folksy demeanor and passion for K–12 education has encouraged many young people to become involved with the sciences. Image from NASA/JPL-Caltech.

  “I could show you a couple of abstracts [for scientific papers] where people speculated that certain Martian meteorites might have been sedimentary rocks, but that was not the thinking of the mainstream Mars science community. People weren't thinking about the presence of rocks on Mars formed from sediment. We knew Mars had sediments because it had sand dunes that have formed by wind—that's a sediment, but they are modern dunes [that is, soft sand and not sedimentary rock]. We knew that the polar caps have layered stuff in them as well. And the thinking was [that] this was a mix of dust that had settled from the atmosphere, which would form a sediment, and ice, which froze in the atmosphere. We knew about that since Mariner 6 and 7. From Mariner 9 we also knew that there were exposures of layered material in places like Valles Marineris [the largest valley on Mars].

  “The key item here is that while these areas were recognized as containing layered deposits of some kind, they were not thought of being like earthly, old cemented sedimentary rock. It seems odd, looking back, but it was just not the way people looked at it. They weren't discussed as being units of rock, and the distinction of that mind-set is they might not have been, they might have been piles of loose, unconsolidated layers of dust or ash or something.”

  But when someone spends eight years looking at hundreds of thousands of photos of Mars, images of increasingly higher resolution and clarity, something seems bound to shift. “Back in 1999 and 2000 we were seeing all these layered rocks. And we could make the case that these were rocks. They were hard. They held cliffs. The cliff would tell you something about the hardness of the material. Craters could be preserved in them. So we told that story in the paper that Grotzinger was talking about. That was a tipping point…that Mars is different—there are sedimentary rocks.”

  Then, among the literally dozens of other papers Edgett worked on during those years, came the 2003 discussion of sedimentation on Mars in a river-delta region near Eberswalde Crater, an area that became a top contender for an MSL landing. “To Malin and myself that area was the smoking gun that some of these sedimentary rocks really were deposited by water. When we wrote that paper in 2000, we talked about bodies of water because a lot of these are in craters, and craters could be a basin where you might have water but couldn't really demonstrate that water did anything.” They had to consider the alternatives to water-deposited sediment to cover all the angles. “We also talked about ways to [create the landform] purely by atmosphere-blown sediment and things like that.” That is, windborne sand and dust as opposed to water-moved sediments.

  They were being cautious, but what they were seeing seemed to lead in only one direction: “One of the things we saw were places where you have repeated layers of similar thickness repeating over and over again.” Rocky strata. “Our experience told us how you can do that with the right kind of fluid properties.” Again, earthly analogues were supplying information that could be applied to what they saw on Mars, and the conclusion led to water.

  In 2003 they were able to confirm their suspicions. “We saw a delta in Eberswalde Crater. That feature is sedimentary rock. It is hard, it has eroded, and the erosion enhanced the appearance of the feature. Where there were stream channels in the delta, now those channels are ridges, they are raised above the surroundings because now they are coarser or more cemented than the surrounding material. That was an indisputable smoking gun that there was a river, a delta, and it went into perhaps a body of water.” It was conclusive evidence of water-deposited, hard-rock strata. And a smoking gun is always welcome in a good mystery tale.

  “These were very ancient sediments that record what kind of environment it was back whenever they were deposited. So then when you fast-forward to the question of why [we chose] Gale Crater and Mount Sharp, the answer is because you have a five-kilometer-high pile of these sedimentary records, which are records of different environments over some period of time. Of course we haven't gotten to Mount Sharp yet and we will never actually do the whole five-kilometer thickness of it, but you have got to think big!” The last statement is said with a flourish, and it makes sense, coming from him. Both these men, Malin and Edgett, had to be thinking big to make the claims they made when they made them. A lot of scientists in a similar situation might have sat on the idea for much longer or waited for even more (possibly redundant) evidence. It can be dangerous to swim upstream too soon in scientific circles.

  Now, when most of us see something compelling and convincing, we form an opinion. But science is a process of forming an opinion based on observed evidence (your hypothesis), then working like mad to prove that you are wrong before you proclaim that you might be right. Edgett discovered an irony—the more images he stared at, the less certain about some things he was. “What happens is that when I see as much data as I have, I find that it makes me more reluctant to really jump in and try to interpret any of it! In some ways it makes me a
better scientist, and in some ways it makes me a worse scientist. The way it makes me a worse scientist is that I am not publishing, and you know it is a publish-or-perish world.” Huh. You would think that a guy who published six major papers in 2000 alone might not have to worry, but what do I know.

  “The way it may make me a better scientist is that I've seen a lot, I've observed a lot, and I still feel like I'm still doing that now with the data from the Mars Global Surveyor and Curiosity. A lot of what I have observed is still in my head being processed.” He made an analogy of how young children who learn multiple languages from the start sometimes take longer to speak any of them. “I've been doing this for going on sixteen years now, and I feel as if I'm still learning the language. I'm not ready to speak, I'm just learning it. What happened in my case, because I look at all this data and I see all these things, you think you know what's happening on Mars. Then Mars throws something new at you, and you suddenly realize what you thought you knew is garbage and you've got to think it through again. And I always get knocked backwards by that process. I should point out this doesn't stop everyone in my field right? The science goes forward, and people [are] finding great things and writing papers about them and announcing discoveries all the time. But I'm always a little more worried and cautious because I've seen too much.”