by Rod Pyle
A new problem arises: there is a short circuit in the TEGA that could affect its operation. This may or may not have been related to the excess vibrating of the sample screen. Either way, the decision is made to stop examining the most promising soil samples and go directly for a water-ice sample, just in case the entire thing stops working. This decision comes right from the top at NASA HQ.
But where to gather the icy sample? The debate on sampling-site selection seems endless. Each trench, each dig area near the lander has its own issues. Some have to do with hardness, as the sample needs to be scraped from hard ice with the drill-like rasp on the sampler arm. Others have to do with positioning: if the ice is embedded in the wall of a trench, it's harder to get at, and so forth, and so on. Regardless, a decision must be made. And there is another consideration: some of the ice nearby seems to be deposited by wind and weather over time (it is, after all, near the surface in a polygon that is formed by thermal changes over time); other ice would appear to have been sheltered and locally formed (as with the white bits found beneath the surface). Mission planners must decide which they prefer, and quickly. It is a battle between sure bets and long shots, between safe procedures and good science. And the mission is very nearly half over…sol 45 is now fast approaching.
It is about this time that the tests they have been conducting with the sample arm—by scraping at the presumed water ice that NASA so dearly wants—indicate that this is not an effective way to get ice samples. They will need to be harvested with the rasp on the end of the sampler arm. This will require up to five days/sols to complete. The midpoint of the mission is upon them, and the attention of many is refocused on other science results like atmospherics, meteorology, and imaging. But time is a-wasting.
Then, three instruments—the robotic arm, its camera, and the TEGA all get uppity on the same day and go into safe mode. They seem to want a day off. In the end, it turns out that the arm ran into a rock while it was carrying out an experiment. Now, when we say “ran into,” remember that this thing moves v-e-r-y slowly…so it's more like it gently nudged a rock. But when you have a half a billion dollars worth of spacecraft working up on Mars, you tend to be careful. So the computer onboard shut it down.
The procedures are reviewed, new commands are sent skyward, and Phoenix is ready for action once again. On sol 52, they are finally ready to get some ice. The arm is pushed up against the suspect white material…the rasp is initiated, and starts spinning…and it works. The icy soil, harder than concrete, had met its match. But this is just a test. A few more sols pass before the real thing takes place.
Finally, at the two-thirds point of the mission, with the clock ticking loudly, some Slurpee®-quality ice slush is transported into the TEGA oven. Things look good. But then the “Oven Full” sensor, that pesky photocell, says, “Nope—not so.” There does not appear to be enough material to heat for a reliable result.
It turns out that the ice samples were sticking to the scoop. This polar mission was turning out to be much harder than doing similar work elsewhere on Mars, and that's already hard enough. It took a third try, on sol 63, before success. The sample was delivered…the TEGA baked it…and the result: water. H2O. Agua. They found part of what they came for, and all (apparently) that NASA HQ sought. There is water on the surface of Mars—and that's a fact.
Soon the other instruments had been fed and given a chance to do their analyses. It turned out that there was perchlorate in the soil after all, just as the “no-life” hypothesizers had maintained while interpreting the confusing life-science findings of Viking. Perchlorate, that nasty, reactive, chlorine-riddled, water-polluting, and rocket-fuel-making chemical was present in the icy soil. This was, like the water story, big news.
Finally, near the end of the mission, calcium carbonate (the same stuff that TUMS® is made of) was discovered in the soil surrounding Phoenix. And it's a compound formed in the presence of water…
Phoenix lasted 155 sols, a bit less than double the ninety-day primary mission. At that point, Martian winter was settling in, intense cold was seeping into the circuitry, and there was simply not enough sunlight reaching the solar panels to power the lander. It went into safe mode, shutting down systems and entering a state of hibernation. Not long afterward, one of JPL's orbiters spotted Phoenix in midwinter, completely encased in dry ice. It was later noted that the solar panels appeared to have cracked from the cold and the weight of the icy buildup.
After the long Martian winter, about two Earth years later, JPL attempted to contact Phoenix, just in case it had survived the long, dark night. There was no response. But this would have been merely a bonus; the plucky machine had succeeded beyond its designers' expectations already, met its mission objectives, and made a number of major discoveries.
Two years earlier, in its final message to Earth, just before it began shutdown procedures, Phoenix flashed a last bit of binary code for anyone who could decode it to hear. It was a defiant last statement as it headed into the cold polar night…
“01010100 01110010 01101001 01110101 01101101 01110000 01101000”
That's binary code for “TRIUMPH.” A bittersweet good-bye from a small, inexpensive, and very successful machine.
Tucson is not the kind of place where you expect a polar explorer to live. And from his compound out in the Arizona desert, surrounded by saguaro cactus and scrub, Peter Smith's view is the, um, polar opposite of the icy environs he has spent time exploring (Smith pulled a stint in Antarctica testing protocols for Phoenix and spent time in the Arctic as well). But perhaps the soil is sufficiently ruddy to bring some familiarity to the scene. Or perhaps it's because he didn't start his planetary-science life with the arid deserts of Mars but with an even more frigid place.
“I was working with a professor named [Martin] Tomasko, an A-level scientist at the University of Arizona, and we were studying the atmosphere of Titan, Saturn's mysterious moon. It has a thick, cloudy atmosphere, so the surface had never been seen. Was it earthlike? Did it have weather? Did it have methane rain? There were lots of questions and few answers.
“We were making computer models of Titan's atmosphere to match the data collected by Pioneer and Voyager flybys, but it was very difficult to bring those models into a conclusion. Deep in the atmosphere, we had no idea what was happening; we were just making guesses. So we proposed to build and operate a camera for the new Cassini mission, which included a lander called the Huygens probe built by the Europeans and designed to descend to the surface of Titan on a parachute.
“Our proposal activities began in 1989, and Huygens actually landed on Titan in January 2005, so it was a sixteen-year commitment to solve this mystery about what was going on in the lower atmosphere and surface of Titan. Dr. Tomasko was quite enthusiastic about doing this and inspired my enthusiasm. My background had been in optical engineering, so I became project manager once our proposal had been accepted, and spent a lot of time at Lockheed Martin in Denver where the camera, now called DISR [the Descent Imager/Spectral Radiometer], was being designed and built. JPL managed our contract with NASA, and representatives from ESA [the European Space Agency] provided the interface to the Huygens probe.
“Scientist to manager was a difficult transition, because contract negotiation, program-management techniques, and quality-assurance methods aren't taught in school. Frankly, sitting in a room with Lockheed Martin's contract lawyers, Marty and I felt like sheep about to be shorn. Sometimes we would make baaaa noises when contract topics were particularly arcane yet potentially vitally important.”1
But despite Smith's modesty, the mission was a success, and new opportunities were on the horizon: “After a few years working on the DISR [Titan] project, there was a NASA announcement of an opportunity to build a camera for Pathfinder, to be the first Mars lander since Viking twenty years before. I had never written a paper about Mars, I hadn't read a book about Mars, I knew essentially nothing about Mars, and yet I knew how to build cameras. We had numerous parts that we were assembling i
nto the descent imager, including lenses, detectors, and electronic control circuits. A subset of these parts became the basis of a Mars camera proposal. Lo and behold, it won the competition over cameras designed by the top Mars scientists in the country…. This dark-horse victory allowed me to leave the long-term Titan project and become a principal investigator.
“After building a prototype at Lockheed Martin, we brought the project to Tucson at the University of Arizona. Now, understand that we had never actually built any flight hardware before, traditionally considered an engineering challenge outside the ability of a university, but we bucked the trend and did it.
“After a thrilling landing on the Martian surface on July 4, 1997, we had a huge success tracking the Sojourner rover as it drove around the spacecraft, and we got tremendous response from the public. It was really fun, and of course I got pushed out from behind the scenes and on stage at the press conferences. Again, this requires talents that you don't learn in school.
“So I had ideas of how a press conference should be. You know, NASA didn't do the best job of promoting these missions, they are talking heads behind a long desk and they can be very dry, they rarely show any emotion. So I wrote up this blurb, assuming it would be successful, and I was the first speaker at the press conference.”
Seated next to him at the press offering was Daniel Goldin, the then NASA administrator. Goldin may have had his own ideas about how a press conference for a major planetary mission should be run, but if so, he didn't share them with Smith: “With Goldin seated right next to me, I started describing the mission as a trip to Mars like a real person would experience it. My camera had a personality. But it was not able to get the best seats on this mission and went economy class. With the parachute crammed down the back of its neck, and a solar panel pressing against its face, the trip was very uncomfortable crushed in between all these components. It took months to get there, then all of a sudden bouncing along on the ground on airbags, bam-bam-bam, finally stopping as the airbags deflate. The solar panels unfold and now the camera named IMP is finally able to raise its head; this is what he saw. And with that introduction, I showed the first panorama taken by the camera.
“So I'm giving that kind of a talk, from the point of view of the camera…as I'm halfway through, I look over at Dan Goldin and he's glaring at me like ‘You are out of business…,’ so now I'm thinking, oh my god, maybe I shouldn't be doing it this way…but the press was enjoying it and we were having fun. Then I showed the first image from the surface of Mars in twenty years and they were really excited, we got a big standing ovation! It was fun and I was really enjoying my new role as camera guy bringing pictures of Mars to Earth.
“The next time I saw Goldin was at a planetary-science meeting…. [H]e recognized me in the audience, so as he left the stage he came right across the room to me and shook my hand. I guess he remembered me for my public-relations ideas. Mission success is what it really takes.”
It was at this moment that Smith realized what space exploration was about for him: “It was exciting for people everywhere; I felt that this was one of the positive things we do in America and give away freely to the world, and so I was very excited about contributing in a small way. Our weather satellites, monitoring of the environment, exploring the planets, all of this is what NASA does for the world and what we as American taxpayers have supported for fifty years. We develop new technology, encourage our young people—it's such a positive message, and that's why I love working for NASA. People need to understand, we don't ship $250 million into space, it's all spent right here in our universities, NASA centers, and aerospace companies. The data advances the science and our knowledge of our solar system. That's where the money goes.”
It is said that no good deed goes unpunished, and NASA's next foray to Mars would seem to have proved this maxim: “The next mission was the Mars Polar Lander [MPL], and I had built another camera system [for it]; it launched in early 1999 with a landing scheduled for December 3, 1999. On the day of landing, it separated from the cruise stage, went into the Martian atmosphere, and was never heard from again. What could we do?”
Between the loss of the Mars Polar Lander and the Mars Climate Orbiter (MCO), NASA and JPL were due for a period of intense internal review.
“I had to fire all the people that worked for me; the mission was over. NASA canceled the next mission, the 2001 Surveyor, on which I was an instrument scientist. My team shrank from thirty-five employees down to one employee. So I limped along for a couple of years until I could propose Phoenix, and Phoenix was the rebirth of the 2001 Surveyor Lander that was mothballed because of these crashes. I had experience with the lander and was a natural PI [principal investigator] for the mission, although frankly, it wasn't even my idea.”
It was not a pleasant time for anyone involved, but they would rise from the ashes of defeat, and brilliantly. The idea came from Dr. Chris McKay, a Mars researcher from NASA's Ames Research Center: “What can be done with the hardware which remains at JPL from the [canceled] Mars Surveyor Lander mission?” he asked.
“We had the Surveyor spacecraft and the instruments that were delivered for its mission. We had a launch date. But we had no science goals, so I had a few weeks to provide the vision that would make the mission attractive to the science review board. This was exciting stuff—what if you could do any mission that you wanted to? I'm just a lucky guy, able to propose a mission to the surface of Mars. My mind went into high gear.
“So many possibilities; I thought about the chances for finding life, about where I would look, under what rock, how would we get there, and what would we do. What instruments would we need? That exact week, one of the professors in my department published a paper about finding ice under the northern plains of Mars. Even though you see it in camera pictures as a dry, dusty plain, he could probe under the surface using gamma rays and neutrons, and could see down about a meter, and his team found that there was a solid ice layer right under that surface. He did this with the Mars Odyssey orbiter, using the gamma-ray spectrometer.”
Smith recognized the opportunity immediately. He had just been handed the keys to an exciting mission—a newly conceived look at the icy polar region of Mars, a likely candidate for past and possibly present life. “So, they had just nailed it, found all this ice right near the surface! If we could go there and understand the history of that ice, and the minerals and the chemicals that are in association with it, that would be an incredible mission. Could that be a place like here on the Earth, where you find these Mars analogs, like in Antarctica and in the permafrost regions of the Earth? There you can find evidence of past life going back millions of years. The permafrost is the deep freezer of the earth. That's where living things are preserved. They aren't preserved in the jungles of the equator where decomposition acts very quickly.
“I once heard a talk from an Austrian scientist who sounded just like Arnold Schwarzenegger…[Smith lapses into an Austrian accent] ‘Ve gather a cubic centimeter of soil and ve put in into our DNA analyzer, and ve can re-create zee tree of life from this piece of soil from zee Siberian perr-mafrost.’ I was amazed—to think that you can re-create the tree of life for the whole Earth from one chunk of Siberian soil, just because it is all preserved there! The winds carry spores, pollens, and microbes of all sorts, and it's frozen into the soil along with the evidence of Siberian creatures. I thought maybe this happened on Mars, and so this might be a good place to look at the history of the Martian permafrost. So we wrote our mission goals around the permafrost of the northern plains of Mars.
“We chose our landing site where the strongest ice signature was seen. We wanted to understand the chemistry and mineralogy of the soil that was in contact with the ice, and to see if that ice had ever melted, because water is a very powerful agent of change chemically and mineralogically. The transition from unmodified volcanic soils that have never seen water to the altered minerals—clays, sulfates, and carbonates—produced in wet environments h
as been well studied by geologists. So we were going to look for altered minerals, and the instruments were picked just for that purpose. What about any organics associated with the ice? To answer that, we had to get a chunk of ice into our instruments and use it to make that determination.”
In May 2008, Phoenix had made its way to Mars and was preparing to land. But after the twin failures of MCO and MPL, tensions were high: “A lot of the managers at JPL were fixated on what would happen to future missions if the Phoenix mission, which of course was a low-cost ‘Scout' mission, were to fail. They felt that it could bring into doubt JPL's ability to land safely on Mars. The unknowns and what-ifs could lead one to imagining terrible outcomes; they worked themselves into such a lather. As a result, we spent a considerable amount of time preparing a press conference for failure. It was so disturbing. We actually rehearsed a press conference revealing how we had crashed on the surface because the parachute had failed.
“So, as we got to the actual day of landing, the press office had written out press releases so that they would be fully prepared after we found out what the failure mode was! We had releases for every likely failure mode, perhaps half a dozen of these things.
“As we are coming down and going through the different phases of the landing, and the failures hadn't happened, the press agent is tearing up and throwing those failure briefings into the air like confetti! I was happier and happier. So finally we got safely to the surface, and, despite predictions, two hours later the first pictures came down. Contrary to some predictions that these first pictures may not show much…they were just spectacular. That to me was one of the great highlights.”
Once on the ground, a communication error delayed the opening of the robotic arm. But it was worth the wait: “About a week later, we finally got the robotic arm working. We wanted to make sure that the landing feet were firmly anchored on the surface, that we weren't tilted up on a rock or something, so we looked under the lander and we saw that the thrusters had blown away the soil and exposed the ice that we had come to find! Unfortunately, the robotic arm couldn't reach under the spacecraft, but it could take pictures with its camera. So here we are thinking, oh my gosh, what if the ice is only under the lander and not beside it where we need it to be? Nonetheless, it was exciting, because we were pretty sure that we were going to find ice at our site. We already knew there was ice in the northern plains, but the spatial resolution was very poor in those maps, so we didn't know if there would be ice exactly where we landed.”
