By Kimm Fesenmaier
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BY Kimm FESENmaier Mission to Mars Close to midnight on Black Friday, 2011, John Grotzinger was standing in the swampy darkness at Cape Canaveral, snapping photos of an Atlas V rocket, when a car pulled up behind him. “Oh boy,” he thought. “This is it . I’m getting arrested.” it wouldn’t have been your typical the illuminated rocket and steel- these people have worked on what’s arrest: Grotzinger leads the team ing himself to be hauled off to jail. inside it, and that this rocket is going of scientists that had prepared the He wasn’t. The man who drove up to deliver their dreams to the surface precious payload atop that rocket— behind him that night turned out to of another planet . To see it up this the Mars science Laboratory (MsL), be one of the engineers from the Jet close in the dark of night is a reminder the most capable robotic mission Propulsion Laboratory (JPL) who had of the miracle of engineering, and that ever sent to the Red Planet. Earlier been at Cape Canaveral doing final we should never take this for granted.” that november day, a colleague had checkouts of MsL’s car-sized Mars When the rocket blasted off the mentioned to Grotzinger that his rover, Curiosity. In fact, with his escort next morning—sending MsL on badge should allow him to get and photography privileges, the engi- its 352-million-mile trip to Mars— a close-up look at the Atlas V. neer was able to take Grotzinger right Grotzinger was cheering with the And so, after a series of uncertain up to the base of the rocket. science team in the bleachers at the turns and a bit of off-roading on the Grotzinger was awestruck. “you Banana Creek viewing area. The launch beach, Grotzinger found himself in get up close and see this enormous marked the end of the first phase of the the dark, just outside the fenced-off thing that you know is going to leave mission for Grotzinger, nine principal launch pad, taking in the beauty of earth,” he says, “and you know all investigators, and their team of about 300 scientists from around the world. That team had worked with engineers to design, build, test, and integrate the suite of 10 scientific instruments that make Curiosity a fully automated, roving geological laboratory capable of collecting and analyzing samples on the surface of Mars. Now the clock is ticking down as they prep for the next phase, when they will begin receiv- ing images and measurements from Curiosity and using that data to seek evidence of a Martian environment Due to Curiosity’s size and mass, a new sky-crane touchdown system will lower the rover to the Martian surface. Once Curiosity touches down, the bridle will be cut and the descent stage will fly away. SUMMER 2012 ENGINEERING & SCIENCE 13 that could have once supported bounce landing like theirs is out of the fied the chemical signatures of clays microbial life. question. This time around, stages and sulfate minerals, which are formed that phase will begin on August 5 will jettison, an enormous parachute through interaction with water, in the of this year when—if all goes well— resplendent in orange and white (in lower parts of the mountain. On Earth, MsL will blaze through the Martian Caltech’s honor) will unfurl, and eight these minerals are often found with— atmosphere, traveling at a speed retrorockets will fire.t hen, in a dramatic and help protect—organic compounds. final act, MsL’s descent stage, posi- All this makes the mountain a promising tioned above the rover, will behave like place to begin investigating the planet’s a sky crane, lowering Curiosity on long past habitability. tethers to the surface of the planet. “We don’t know what the story is going to be at Gale Crater, but we’ve got WE LCOME TO GALE CRATER a wonderfully simple exploration model,” That action-packed entrance should Grotzinger says, “We’ll just start at the leave the rover poised on all six wheels bottom of the mountain, interrogate the inside Gale Crater, an ancient impact layers and make the crater just south of the Martian equator. measurements, and see roughly the size of the Los Angeles what the planet’s trying Basin—at 154 kilometers (96 miles) in to tell us. I don’t think diameter—the crater is the kind of place we can lose.” geologists would head to on Earth to Ideal though the search for evidence of past life. They location may be, it took hope to find organic compounds, the the scientific commu- carbon-containing chemicals consid- nity about five years to ered necessary for life. so finding the settle on Gale Crater of some 13,200 miles per hour. in crater on Mars, at a safe elevation with as MSL’s landing site. less time than it takes to boil a pot moderate environmental conditions, “the amazing thing is of water—a nail-biting period known made it a natural choice for the mission. that, thanks to MSL’s as the “six minutes of terror”—the The floor of Gale Crater is at a low landing system, we spacecraft will go through a series elevation relative to its surroundings, scientists got to con- of maneuvers to put on the brakes which means that if water once flowed sider—for the first time and touch down. this will be no across Mars, Gale might have been a ever—the absolute best small feat: at nearly 2,000 pounds, location in which groundwater col- places on Mars,” says Curiosity weighs more than five times lected and perhaps even emerged as Grotzinger. “the whole as much as the previously launched an ancient lake. But the main attraction time we were debating, Mars exploration rovers (Mers) at Gale is a mountain that rises five I had seasoned veter- spirit and opportunity, so an air-bag kilometers (three miles) from the crater ans telling me, ‘John, floor.t he science team has dubbed don’t get your hopes this geological feature Mount Sharp up, because in the end Above: Curiosity’s landing plan puts it within Gale in honor of the late robert P. sharp (Bs engineering constraints Crater, an impact feature on Mars that’s more ’34, Ms ’35), the beloved former chair will probably kill all of than 3 billion years old. The layered mountain at of Caltech’s then Division of Geological these choices. Be prepared to accept its center, dubbed Mount Sharp by the science sciences, who built the institute’s pro- whatever’s left on the table.’ But we team, is a major scientific focus for the mission. gram in planetary sciences. Scientists didn’t have to settle. In the end, we Right: These are replicas of the wheels on hope to use Curiosity and its scien- chose the site that was actually the Sojourner (center), the first rover on Mars; the tific instruments to read the history of science team’s favorite, and the Mars Exploration Rovers (left); and Curiosity (right). Mars by characterizing Mount sharp’s engineers could support it.” Curiosity’s wheels are approximately 20 inches strata—beginning with its oldest layers (50 centimeters) in diameter while Sojourner’s were at the bottom and inching up to those SAM I AM closer to 5 inches (13 centimeters). deposited more recently. Previous Curiosity is uniquely equipped to select, orbital missions have already identi- sample, and analyze rock and soil 14 ENGINEERING & SCIENCE SUMMER 2012 targets once it arrives on Mars. Indeed, Once Curiosity drills into a rock or wipe away traces of organics because JPL deputy project scientist Ashwin scoops some soil to harvest a sample, it is also an oxidant. So even if life had Vasavada (PhD ’98) describes the rover its six-foot robotic arm will go through once thrived on Mars, scientists would as “a Mars scientist’s dream machine.” a series of tai-chi-like maneuvers to be hard pressed to find traces of it.i n its onboard tool kit includes not only process and deliver the materials to fact, on earth—a planet that teems with devices that are the equivalent of the the rover’s belly, where they can be life—the record of life in the form of hand lens and drill geologists rely upon analyzed by two advanced onboard organic matter is rarely preserved over in the field, but also the spectrometers laboratories. one, called CheMin, will geologic time. and other analytical instruments they use X-ray diffraction to identify minerals Not to fear, though: MSL’s success might use in the lab to identify the in the sample. the other, called sAM does not hinge on finding organic chemical elements, minerals, and gases (for sample Analysis at Mars), is a suite matter. simply by driving up the mound in their samples. The rover sports sev- of three analytical instruments—two in Gale Crater, taking samples, and eral cameras that will allow it to observe spectrometers and a gas chromato- reading the layered record it encoun- its surroundings in high definition and graph—that can check for large organic ters, Curiosity will improve our under- molecules and other important chemi- standing of the evolution of Mars. And cal elements, measure isotope ratios if it can reach a spot about a quarter to look for signs of past planetary of a mile (about 400 meters) up Mount changes, and determine concentrations sharp, it should find a break point that of gases in both surface samples and may mark a geologic transition between the Martian atmosphere.