DHG: Dyar Describes Her Mars Mission Work
This article originally appeared in the August 11, 2012 edition of the Daily Hampshire Gazette.
By Rebecca Everett
Four days after she watched the rover Curiosity touch down on Mars while standing in a NASA laboratory in Pasadena, Mount Holyoke astronomy professor Darby Dyar is still reeling.
"I've never seen so many grown men cry," she said, recalling the relief she and her fellow scientists felt when they watched the rover land safely Monday.
But the really exciting stuff will happen over the coming months, as Dyar and a team of researchers working from the South Hadley campus take on the paramount task of identifying the rocks on Mars. Using rock samples and a weapons-grade laser, they can establish the chemical composition of Martian rocks, revealing important information about the make-up of the planet, including whether it possesses the elements needed to sustain life.
"It's hard to be patient," she said of waiting for the results to start coming in from Curiosity. "Probably the rest of my career is going to be this project."
For Dyar, 54, a planetary scientist from Amherst, the mission is the culmination of seven years of work with NASA. The agency tapped her in 2005 to be part of a team of scientists to determine how best to analyze Mars' rocks and soil. What they came up with is an apparatus made up of a laser, a camera, and a spectrometer - an instrument used to measure light properties. Their creation, nicknamed "Chemcam," is now mounted on the Mars rover.
Standing in a small laboratory in Mount Holyoke's Carr Laboratories Thursday, Dyar explained how Curiosity uses the Chemcam to investigate Martian rocks, as the College's own Chemcam does similar work.
While rolling across the planet's surface, the rover can fire the laser at a rock up to 24 feet away, heating a tiny part of the rock to 3,600 degrees Fahrenheit and transforming it into a plasma. A fiber optic cable records the light spectrum produced by the glowing plasma, and transmits that data back to Earth.
Another Chemcam is going through the same process at Mount Holyoke in order to create a library of spectra to compare the Mars spectra to.
In the college's mineral spectroscopy laboratory, the laser shines into a small chamber that has been pressurized and filled with carbon dioxide to recreate Mars' atmosphere. In the chamber, powdered samples of Earth rocks are heated to a plasma by the laser and their spectra are recorded and transmitted in the form of a graph to a nearby computer screen.
Each chemical element in a rock puts out a unique spectrum, Dyar explained. So by comparing the spectrum of a rock on Mars to the spectrum of an Earth rock whose composition has already been identified, the make-up of the Martian rock can be determined.
To put it in less scientific terms, "we'll match it against our library of wiggly lines, and essentially figure out what's the best match," she said.
She indicated the shelves of the lab, which contain boxes with hundreds of rock powder samples, labeled and recorded to create the "spectral library" scientists can refer to when they start getting data back from the rover. Over the next few years, Mount Holyoke scientists will analyze thousands more samples to compare to the 10,000 spectral samples Curiosity will collect on Mars.
NASA awarded Dyar a $476,000 grant in June to do the analysis.
She said the Mars rover is equipped with an arm to do more in-depth analyses of rock, but it can take the rover hours to roll over to the rock, lower the arm and get to work. That's where the Chemcam's 24-foot range comes in handy.
"This way, before we go to the trouble of doing all that, we can know something about the rock and know which rocks to analyze further," she said in the lab, talking over the hum of the laser warming up.
Behind her, research laboratory manager Elly Breves did the required verbal countdown before pressing the button to start the laser.
Dressed in jean shorts and a sweatshirt instead of a lab coat, Breves went through the required safety procedures, including warning that looking at the laser could seriously damage your eyes, even though the laser is completely obscured by the Mars chamber. "Don't press any buttons," she concluded.
She killed the lights as the laser beamed into the chamber, illuminating it with an eerie green glow. The sample glowed white and seemed to pulsate as the spectrum data - the "wiggly lines" - showed up on a graph on the computer screen.
It takes less than 10 minutes to go through the process of analyzing and recording each sample, Dyar said. Breves, who is actually a chemical oceanographer, spends her days doing the spectroscopy in the lab. A UMass computer science graduate student, Marco Carmosino, is working on the software that will allow scientists to access the spectral library.
Dyar will split her time between Pasadena and South Hadley for the first 90 days of the mission, when the scientists are expected to live and work on the NASA campus to promote collaboration. After that, she will work remotely from the Mount Holyoke lab. She said the weeks before and after the landing have been exhausting, but working alongside some of the best scientists and engineers in the world is thrilling, even if she is sleep-deprived.
"This is one of those things that is so complicated, you can't do it yourself," she said. "When I was in graduate school, the goal was to write a paper and be the sole name on it. But the most exciting things in science now are done collaboratively."
She said one aspect of her work she is still getting accustomed to is "living on Mars time."
During the Martian night, the rover is inactive, or as Dyar calls it, "asleep." She and the other scientists need to do their work while the rover is "awake," during the Martian daylight hours. Since each Martian day is about 24 hours 40 minutes, each day the scientists have to go into work 40 minutes later than the day before to synch their work with the Martian schedule.
Dyar said it will be months before the database and software will be available to cross-reference the Martian rocks, but scientists have nothing but time. "The rover is nuclear powered," she said. "It's quite likely this thing could go on for 10 to 15 years."
Among the "big picture questions" Dyar said scientists are trying to answer is whether there is - or was - life on Mars.
"I think there's a good chance there was once life on Mars," she said. The Chemcam will be able to look for rocks containing carbon, oxygen, and water.
"Those are the building blocks of life, or at least, life as we know it," she said.
If an unlucky Martian did happen to cross paths with the laser-armed rover, he or she would be vaporized, she added. She is pleased the attention focused on the mission gives her a "stage to showcase" the quality of the college's science programs.
"We're a liberal arts college but we really do first-class scientific research here," she said. "Just because we don't give out PhD’s doesn't mean we don't do really high-level research."
The Chemcam on campus could be used by students for independent research, but it won't be used for classes, except perhaps as a demonstration, Dyar said.
The campus is buzzing about the project, she said. "Everywhere I go on campus, everyone knows about the mission and congratulates me. Someone brought champagne to a meeting," she said.
And that excitement over the Mars mission is what she finds most satisfying about her work on the project.
"Participating in a Mars mission, sure, it's about looking for life and the achievement of landing a rover on a another planet. But for me, the most important thing about this is actually that kids and people on the street are talking about science," she said. "Our world needs this desperately."
Rebecca Everett can be reached at email@example.com.
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