This article originally appeared in the Daily Hampshire Gazette on Tuesday, January 29, 2013.
SOUTH HADLEY — As she walks across the Mount Holyoke College campus, people often greet Darby Dyar, professor of astronomy and geology, with this: “How are things on Mars?”
It’s not a tease. They’re not making a crack about her being from another world or having her head in the clouds. They recognize her as one of the scientists behind the most advanced discovery mission to Mars, which began in earnest in August when the Curiosity rover touched down on the red planet.
“My 15 minutes of fame is stretching to 15 months of fame,” Dyar said in a telephone interview from her office on the South Hadley campus.
Normally at this time of year, Dyar, 54, would just be starting the spring semester at the college, handing out assignments to geology and astronomy classes. But these days she is spending most of her time working with a team of scientists to give assignments to Curiosity, as the rover rolls over the surface of Mars, testing the atmosphere, scooping soil and even zapping rocks with a laser.
She is technically on leave, but still spends most of her days working in her office or lab at the college, said Assistant Dean of Faculty Eleanor Townsley. And although Dyar isn’t teaching classes, the college is thrilled with her involvement in the Mars mission.
“Darby is a star,” Townsley said Monday. “She is a very committed and generous teacher.”
She said Dyar has research assistants helping her with her work on the Mars mission, which gives these Mount Holyoke students a rare chance to be a part of a NASA space mission while they are undergraduates.
In 2005 NASA hired Dyar and a team of scientists to find the best way to analyze Mars’ rocks and soil. They created something they call “ChemCam” — an apparatus on the rover’s arm that shoots a weapons-grade laser at a rock up to 24 feet away, briefly heating a tiny piece of the rock to a plasma. A fiber-optic cable records the light spectrum produced by the glowing plasma and transmits that data back to Earth, where its makeup will be identified by comparing its spectra to a library of spectra being created at Mount Holyoke by an identical ChemCam.
And though the ChemCam is her area of expertise, Dyar said she has been enthralled by every aspect of the Mars mission. From the regular teleconferences with other scientists to decide what instructions to give Curiosity, to the big discoveries, like the evidence of long-gone streambeds, she’s hooked.
“As a geologist, it’s frustrating not to be there, but as an analytical geochemist, it’s incredibly exciting,” she said. “It shows that with this incredible instrumentation, we don’t have to be there.”
After the rover landed on Mars on Aug. 6, Dyar and her scientist colleagues spent three months working at NASA’s Jet Propulsion Lab in Pasadena, Calif., and living on “Mars time” to sync their schedules with the rover’s. Because the rover is active during daylight on Mars, and each Martian day, or sol, is about 24 hours and 40 minutes, Dyar and her colleagues had to go to work each day 40 minutes later than the day before.
Dyar said she is grateful to be back on Earth time — and back in her own lab at Mount Holyoke College. And like Curiosity, beaming data back to the lab, she is armed with technological tools that make it possible for her to work on the project without being in Pasadena.
To keep up with the day-to-day operations of Curiosity, she and the ChemCam team of scientists use video chat programs to teleconference, sometimes daily.
“Every day we look at what the rover did the day before and the pictures, and then we decide what interesting science we want to do that day,” she said, referring to sols. “It’s this cycle of sending instructions, getting data back, and analyzing it quickly so we can give it more instructions.”
She said the rover wakes up at sunrise on Mars.
“It’s like a 5-year-old. It wakes up and looks for instructions,” she said of Curiosity. Some days it takes longer than others to align the technology in a way that transmits those instructions.
“A satellite has to be overhead for the rover to send or receive data, so sometimes we have to wait for later in the day to give instructions, or we might give it a task the day before,” she said. The rover reports back with data at the end of the sol.
Curiosity’s tools to collect data range from a camera to a scoop that picks up material and drops it into the rover’s chemistry lab for analysis. Since Dyar’s team is concerned with the ChemCam tool, their daily task is to find a target or many targets that look interesting, name them, and then tell the ChemCam to shoot the laser at them.
“We’re taking in data like mad, but we haven’t analyzed it yet,” she said. The rover has collected spectra samples 25,000 times. Back at Mount Holyoke, research laboratory manager Elly Breves has been working for months to build up the spectra library, and has so far analyzed 5,000 samples to compare to the Mars samples.
Roger Wiens, ChemCam principal investigator for the mission, said via email that teammate Dyar is “hard to keep up with.”
“She is a veritable Energizer bunny — always brimming with ideas on multiple projects all at the same time, with multiple students in tow,” he said.
Looking for life on Mars
The main goal of the mission is to find either evidence of current or past life on Mars, or proof that the planet once possessed the right conditions for life to exist.
Dyar said she thinks there’s a good chance there was once life on Mars, and a number of the rover’s discoveries involving water support that possibility.
“Essentially, Mars today is cold and dry with very low humidity,” Dyar said. “But we know that at some point, like 4 billion years ago, the surface had much more water.”
The most exciting clue by far, she said, has been the photographic evidence that streams of water once flowed across the surface. Photographs Curiosity took in September in the bottom of a canyon show smooth, rounded rocks, similar to those found in an earthly stream or ocean. Not only were the rocks apparently shaped by water, but they seem to have been deposited there by streams that once cut channels downhill.
NASA scientists estimated that the stream flowed at a rate of 3 cubic feet per second and was between ankle and hip deep. That’s far slower than the Connecticut River, which travels at about 10,000 cubic feet per second in Holyoke.
Dyar has a strong feeling that another exciting discovery will be made in the near future, because the rover is preparing to drill into its first rock. While other Mars rovers have collected samples on Mars, Curiosity is the first rover capable of drilling 2 inches deep into rock or soil.
Dyar’s preferred drilling site on Mars is Yellowknife Bay, an area the rover rolled into on its way to its ultimate destination, a 3.4-mile-high mountain called Mount Sharp. But what it found there was so interesting, scientists decided to delay the months-long trip to Mount Sharp to investigate the bay.
“What we found was a weird area where the daily temperature doesn’t vary much,” she said. The reason could be what the ground is made up of, as different minerals have different thermal inertia, or ability to hold onto heat. But the answer could also be water-related.
“A lot of ice in the subsurface would keep the ground temperature the same,” she said. “But we don’t know what it is at this point. That’s why we want to drill.”
After drilling, Curiosity will start, likely in February, to head to Mount Sharp, which Dyar described as a “layer cake of sediments” that can take scientists on a “journey through geological time.”
The mountain’s stratification suggests that it may contain a series of deposits after a massive impact that likely created the crater over 3 billion years ago, NASA scientists have said. Since they think the planet was more likely to have sustained life back then, likely the best place to find the chemical building blocks of life — complex carbon-based molecules — is in that dusty layer cake.
When she isn’t sending robot instructions to Mars, Dyar gets a kick out of people recognizing her on campus. It’s not the celebrity that she loves, but the fact that people still care about Curiosity, even six months after the dramatic landing, when the news is more about rocks and soil.
“A model of the Curiosity rover was even in the inauguration day parade, with NASA scientists accompanying it,” she said. “We have worked hard on this mission to make outreach work effectively.”
Besides offering press releases, photos and videos on the JPL website, Curiosity’s public relations team is having fun with the news to keep even non-scientist types interested. Curiosity has Twitter and Facebook pages, where it offers jargon-free updates and science puns, like, “Giving Mars the brush-off” in a Jan. 10 Tweet about a video of the rover using its dust removal tool.
“There’s still a lot of interest from the general population,” Dyar said. “I think that’s great.”
Rebecca Everett can be reached at firstname.lastname@example.org.