Red Rover

by Roger Wiens

  In giving Mars talks to various groups, John had noted that the public had identified the most with the crater site that contained a large river delta. This was a feature everyone could relate to—it showed that there had truly been a river and a sea there at one time. The site, called Eberswalde, also captured the imagination of Ed Weiler, the top NASA official involved in the decision. Eberswalde appeared to have a slight lead over all of the other crater sites. John thought we might be able to build a consensus around Eberswalde. We really did want as strong a consensus as possible on whatever site ended up being selected.

  The meeting began. There were presentations and discussions on each of the four sites. Each one still had strong proponents. The first two days went by with nothing to break the tie. We were being worn down by the tedium of the long meeting. The final day would mostly be “open mic” for whoever had anything more to present. The evening before, I had been cornered by Bibring and another French colleague. We had talked for several hours about all the details, about what ChemCam would do at the different sites, and about various other developments in the field. In the end, Bibring looked me in the eye and announced, as he gripped my hand, “You will vote for Mawrth. I know you will make the right decision.”

  All the next day, I could see Bibring pumping for votes among the different Curiosity team members. Like his Parisian French, his English came out faster than most Americans could speak. But, if anything, the hard lobbying seemed to be turning people off. Several new presentations were made, but still there was no front-runner. John Grotzinger’s thoughts that Eberswalde might rise to the top clearly were not being fulfilled. After some final statements, the Mars community meeting was adjourned without a decision.

  It would be up to the Curiosity team to decide the matter the next day.

  The Curiosity session was held in a new building on the Caltech campus, a welcome change of scenery after too many days in hotel meeting rooms. We all piled into a large lecture hall. Although our group was much smaller than the community gathering, there were still nearly fifty of us. Notably absent were Bibring and some of the spectroscopists, who were not officially part of Curiosity. John Grotzinger took the floor and welcomed us. He immediately called for a vote to see where the team stood. We all held our breath, fearing a continued stalemate. But this time there was a clear ranking. Bibring’s favorite site came in a distant third. Two of the crater sites, Eberswalde, with its river delta, and Gale Crater, with its tall stack of sedimentary layers, were at the top, but Gale had a significant edge. We had the whole morning, so we discussed a number of things. Would delaying the decision help? The engineers and navigation team could wait a few months if we really needed more time to decide. But no, no one thought more time was needed. In the end, one more vote was taken after the fourth-place site was removed, and again Gale was on top. The meeting ended and we grabbed lunch.

  The inner circle met for the afternoon. We discussed landing safety. Again, Gale had several advantages here—it was near the equator, and the landing area seemed to have fewer large boulders and steep slopes than the other sites. The engineers would like this choice as well. Gale would be the place.

  The results of the Curiosity meetings were to be kept secret. We didn’t have the final authority, which rested with the selecting NASA official. He would likely take our advice, but one shouldn’t presume to be sure of the outcome. Ed Weiler would be briefed in Washington within three weeks. Then the news would come out. Unfortunately, the results leaked out early. Bibring was furious that his site was not picked. He and some of the NASA officials found themselves in an unrelated meeting just two weeks later, where, in front of the crowd, he had strong words to condemn NASA officials if they did not pick wisely. A rumor suggested that Bibring believed that life in our solar system had started at Mawrth before coming to Earth, and we would miss our chance to learn about our origins if we did not land there. Bibring wrote letters to various people up the chain of command and even managed to have breakfast with the head of NASA, where he used the opportunity to discuss the matter. Meanwhile, in June, a news article came out, beating NASA to the punch in announcing the landing site. The article, which didn’t quote its sources, read like a tabloid. It was now NASA’s turn to be upset. Bibring’s site would certainly not be selected, but NASA also decided to postpone the announcement to let the dust settle. Finally, in July, after the last space shuttle had made its final voyage, the Mars landing site was announced during a special Mars event at the Smithsonian Museum. Curiosity would go to Gale Crater.

  chapter

  twenty-one

  BACK TO THE CAPE

  IT WAS PITCH BLACK WHEN THE RADIO CAME ON AND GWEN poked me awake. But I was happy to get up. This was going to be the start of a fine adventure. It was November 2011, almost exactly a decade since I had been at Cape Canaveral for the launch of the Genesis mission. A lot had happened in the intervening years. Genesis had flown and landed. Its science team had—wonder of wonders—published the results. And, just as amazing, we were now sending a new invention to the surface of Mars. Other things had happened as well. The space shuttle Columbia had failed to make it back to Earth; our SCIM mission was never selected; and, ultimately, the space shuttle fleet had been retired.

  Gwen and I had raised our children during that decade. Carson was now eighteen and taking trips to visit colleges and universities. Isaac was in high school. I thought back on the last launch trip with the family. That time we had their grandparents along and still we could hardly keep up with the little boys. Now they were sophisticated teenagers. What a difference a decade makes!

  The airline had changed its schedule after I had booked my flight, making it necessary for me to get up two hours earlier than I would have liked. As compensation for the premature wake-up, I hoped to glimpse our reason for the trip, the planet Mars, which, according to the night-sky guides, was now shining with increasing radiance in the morning sky. Unfortunately, there were high clouds overhead. I could see a diffuse glow from the Moon, but I could not make out any stars. Maybe the clouds would go away in time, before the dawn became too bright. I drove through our small town and down the mountains into the Rio Grande Valley. As I took the bypass around Santa Fe, the clouds seemed to be thinning, but it would likely be too late. I could also see the first light of morning behind the Sangre de Cristo Mountains. Sure enough, a short time after turning onto I-25, I saw my first patch of clear sky, but there were no stars to be seen; it was too light.

  Gwen and I texted each other after I reached the airport. She and the boys would come on Wednesday, after school had dismissed for Thanksgiving break. The week promised to be a full one. Tuesday would be a triple-header: a meeting for the science team and then a news conference, and finally a talk for a group of educators there for the launch. For Thanksgiving Day, our French colleagues had organized an international soccer tournament, and after that—the launch.

  Next to the launch itself, the soccer tournament was the highlight of the week. The Sun was shining brightly when we got to the playing fields. The warm weather and the verdant St. Augustine grass belied the fact that it was late November. A large group was milling around near the entrance to the fields, mostly clustered around Pierre-Yves Meslin, the French organizer of the tournament, and Bruce Barraclough, our project manager. Back in Los Alamos, Bruce had refereed soccer games for years. Here he was wearing a polo shirt rather than his striped referee’s shirt—he was going to play this time. People were dressed in various types of clothing: some, especially overseas colleagues, had professional-looking soccer outfits. Others were dressed in jeans or casual shorts. Sylvestre and his wife Armelle had brought one of their four daughters with them from France, and in spite of her size, nine-year-old Colombe was determined to play. Carson and Isaac were also ready for action.

  The crowd continued to grow. It was a grand reunion of all the people I had worked with in the past seven years, along with many scientists and technicians from other instrument tea
ms. In all, over 140 people showed up for the tournament. The organizers divided the players into eight teams for double elimination. Each game consisted of two ten-minute halves on short fields. The members of the Spanish team named themselves “World Champions,” though they proved to be much better at science than soccer, ending up in eighth place. The winning French team had to rub it in. Fortunately, everyone practiced restraint and there were no injuries, either to bodies or to egos. Afterward everyone enjoyed a picnic lunch. My family finished off the day by picking up a ready-made Thanksgiving dinner at the grocery store and hosting Sylvestre and French team member René Perez and their families in our one-room condo. We told them about the events that, on another shoreline in North America four hundred years earlier, had led to our celebration of this holiday.

  The reason we were all here, of course, was the impending launch of Curiosity to Mars. No matter where I was or what I was doing, my mind was always picturing the Atlas V rocket with Curiosity on top, sitting on the launchpad not far from the surf.

  The Atlas line of rockets had had a long and successful history. The first one was developed in the late 1950s as an intercontinental ballistic missile. However, it was the booster of choice when NASA needed a reliable rocket for the orbital flights of the Mercury program in the early 1960s. Surprisingly, it was not strong enough to support its own weight unless the fuel tanks were filled with either liquid or pressurized gas: it used what were called balloon tanks—tanks whose thin walls, along with the internal pressure, provided the support for the upper part of the rocket. Not having any dedicated support structure made the Atlas rockets much lighter than they would have been otherwise, allowing more payload mass to be sent to orbit. At least one rocket had lost pressurization in its tanks and collapsed in the early 1960s, but this was a rare event. The rocket continued to be used for dozens of unmanned launches for the military over the next several decades.

  The Atlas line was almost totally redesigned in the 1990s. Internal support was added to the tanks, among other changes. The new vehicle actually used a Russian-designed RD-180 engine, which was ironic for a rocket that started out as an ICBM in the Cold War. The Atlas V that was to launch Curiosity was officially a version 541, which meant that it had a payload faring 5 meters (16 feet) in diameter, four solid-fuel strap-on boosters at its base, and a single-engine Centaur second stage. The main core of the first stage held large tanks of kerosene and liquid oxygen and stood more than 100 feet tall. The total height of the rocket was about 200 feet, and it weighed nearly 350 tons. The most recent Atlas V launch had been in early August, sending the Juno spacecraft toward the planet Jupiter, where it would achieve orbit after five years on a mission to study the interior of the giant planet.

  The Curiosity flight plan called for a morning launch with a window of about two hours each day. A couple of minutes after launch, the rocket would drop its four expended solid-fuel boosters. The payload faring covering the Curiosity capsule and the second stage would be released at T equals three and a half minutes. The main booster would continue to burn for a little over four minutes from launch, achieving an altitude of 100 miles and going several hundred miles downrange. After separation, the upper stage would insert the spacecraft into an elliptical Earth orbit. However, before completing one revolution, at the proper position relative to Mars, the engines would fire again for eight minutes to direct Curiosity out of Earth orbit and toward the Red Planet. Four minutes later, the Mars cruise stage would be separated from the second stage and on its way.

  This was the first major launch at Cape Canaveral since well after the conclusion of the Space Shuttle program, with the last shuttle, Atlantis, returning to Earth July 21. It was of significant interest for people who wanted to see another launch as well as to the many people excited about the future of Mars exploration. The crowd on hand to watch was estimated at around thirteen thousand. Since I had missed the Genesis launch, this would be my first one.

  At last the long wait was over. The excitement in the crowd grew as the last minutes, and then seconds, ticked away. The countdown reached zero and everyone was suddenly quiet, but only for an instant. A loud and continued roar rose from the crowd as we saw the smoke, the flame, and the ascending rocket. I shouted, “Go, go, go!” as the vehicle cleared the tower. Seeing it from this distance, I couldn’t help thinking how much it looked like all of the rocket launches I had seen in our backyard as a kid. Now trailing a long tail of fire, the vehicle disappeared momentarily into a cloud, then reappeared above the cloud layers. Finally, the sound of the engines reached our ears as a low and sustained rumble. The rocket arced out over the Atlantic Ocean and grew smaller and smaller. A TV monitor showed the long-range view of the rocket for a short time, and then everyone headed back to the buses, talking excitedly.

  During the ride back from the viewing area, we continued to receive e-mails from JPL on the temperature of our instrument, as well as public announcement tweets indicating that all systems were working well and the final separation of the capsule had been successful. We breathed a sigh of relief. A Russian mission to Mars’ moon, Phobos, which had launched just weeks earlier, had failed to leave orbit and was doomed to crash back to Earth. It made us all the more thankful for our success, and reminded us of the risky journey ahead.

  The next day’s newspaper headlines around the world captured the spirit of the “Go, go, go!” I had shouted during the launch. I couldn’t believe it—we were really on our way to Mars!

  During our last night in Florida, I took a break from packing the family’s bags and walked out onto the beach. It was very late. I stepped carefully to the edge of the water; the foam from the breaking waves was the only thing visible in the dark. The winter constellations were shining brightly in the east above the ocean. I thought I could see Mars’ red glow low in the sky. I thought about Curiosity. At that moment it was somewhere between me and Mars, speeding away from planet Earth.

  chapter

  twenty-two

  SEVEN MINUTES OF TERROR

  THE NEXT MAJOR EVENT IN CURIOSITY’S JOURNEY WOULD BE the landing. The center of the action on Earth would be JPL, where the signals would be received from the deep-space network antennae.

  In comparison with the launch, landing on Mars is statistically far more risky. The Atlas V that powered the Curiosity rover up and away from Earth had a better than 95 percent success rate. In contrast, there had only been a total of six successful landings on Mars out of the many attempts by the United States, the Soviet Union, and the European Space Agency—a rate of well under 50 percent. NASA had not had any failures with its three Mars landings in the past decade, but the risk of crashing was formidable, and much greater than NASA would like to admit.

  Just after ChemCam’s 2007 cancellation, I added a new slide to the presentations I gave around the country. It showed the likelihood of success from the beginning of a hypothetical project like ChemCam to finally making measurements on another planet. Every project starts as a gleam in someone’s eye—an idea. Like a seed, an idea may stay dormant for a long time, waiting for the right season—the right environment—in which to germinate. There are thousands of ideas for planetary exploration floating around, but the likelihood of success for any one of these is extremely low. The idea has to get fleshed out, and that takes money. So the next point on my graph was winning an instrument development grant, usually from NASA for projects in the United States, but sometimes from other sources. With some money in the bank, a prototype can be built (as we built and tested precursor models before ChemCam) and the concept can be demonstrated. Still, although NASA awards new instrument grants every year, very few of them make it to flight.

  At this point the line representing the chance of success has barely moved upward and still shows a likelihood of success of less than 10 percent. The instrument concept might win another round of development proposals, potentially upping the odds a little. The next big break requires getting selected for flight. With a promised ride int
o space, a concept now has something like a 30 percent chance of making it to a destination like Mars. My chart then shows a steadily climbing line as the project passes required milestones, the two biggies being the preliminary and critical design reviews. In the case of ChemCam I showed a huge and sudden dip back to near zero labeled “Cancellation!” Fortunately, we got past that hurdle and climbed back onto the ascending curve. After that comes the instrument’s delivery to the spacecraft. As the spacecraft is tested, the probability line rises steadily. At the point labeled “launch,” the line jumps up a bit. The launch itself carries a risk of approximately 5 percent.

  The biggest single hurdle was yet to come for Curiosity. In my chart I showed the landing risk at between 20 and 25 percent. After that, the line is near the top, but not quite there yet. The last 5 percentage points were reserved for actually making the first measurement. It was possible that an instrument could make it to its destination and then not work. It had happened on a number of instruments.

  All of the times I had shown this chart to date had been well prior to launch. The chart clearly showed the audience that we were not very close yet; the odds of not making it were still nearly one in two or one in three, depending on when I showed the slide. I would point out how far we had to go in our chances for success, and the listeners would become rather sober, perhaps thinking in the back of their minds that we were crazy to attempt such a daunting feat. Then I would quickly flip to the next slide to show the same line plotted on a logarithmic scale, indicating graphically that we now had orders of magnitude better odds than when the idea was first birthed. The new slide showed the current position comparatively near the top, and the audience would invariably laugh at my sleight of hand and my optimistic viewpoint. Yet, I knew that we still had a long way to climb up the curve to success.