October 21, 2015

Water Now — Walking on Mars Next? Princeton Junction’s James Wray Leads the Way

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MARS, HERE I COME!: James Wray, Princeton Junction native, now Georgia Tech Professor of Earth and Atmospheric Sciences, led a research team that confirmed the presence of water and the possibility of life on Mars. He’s eager to follow up on that discovery. (Photo Courtesy of James Wray)

When James Wray was a senior at West Windsor-Plainsboro High School South, he had ambitious dreams. According to a May 2002 Star Ledger article, “James hopes some day to become an astronaut. ‘I’ve always dreamed of walking on Mars,’ he says.”

Well, not yet, but it looks like he’s on his way.

Flash back to a TV news conference on Monday three weeks ago, where NASA scientists were preparing to announce that liquid water is flowing on the surface of Mars, providing a crucial clue that life might exist on the red planet. 

The director of a significant portion of the research leading to that discovery was Mr. Wray, who is now an assistant professor at Georgia Tech and a co-investigator on several NASA research grants involving analysis of data from Mars.

Mr. Wray has been investigating the mysteries of Mars and other planets at least since his undergraduate days at Princeton University, where he wrote his senior thesis in 2006 on the icy moons of Jupiter and Saturn (“High-Dispersion Spectroscopy of Europa and Enceladus: Probing the Tenuous Atmospheres of Active Icy Moons”).

At Georgia Tech he has taught classes on physics of the planets, Earth and planetary materials, remote sensing of land surfaces, and a seminar on “astrobiology” (the quest to find life beyond Earth and to understand how it evolved). He has led research groups studying planetary surfaces, with a focus on Mars and those icy moons of Jupiter and Saturn. “We make extensive use of NASA mission data, and therefore I also spend a fair amount of time working at NASA labs,” Mr. Wray explained.

Since the 1970s scientists have suspected that water flowed on Mars billions of years ago, and even earlier they surmised (from telescopes) that even today the polar ice caps retain water in the form of ice. But because the planet is so cold and dry and has so little atmosphere, the presence of liquid water today was considered impossible, until a few years ago.

Pursuing the Mystery

In 2010, while Mr. Wray was finishing his PhD at Cornell, he learned that images from the Mars Reconnaissance Orbiter were revealing “dark streaks (a few feet across), which would appear in the summertime and slowly extend (up to hundreds of meters) downslope, before fading away over the winter.” This phenomenon was consistent with flowing liquid water, but the presence of liquid water could not be proved.

“I knew a way to prove it,” Mr. Wray declared, “using infrared spectroscopy to look for the diagnostic ‘fingerprint’ of water and/or salts it would leave behind after evaporating. I looked for this in 2011 but didn’t find it.”

Finally, according to Mr. Wray, “Everything came together in January of this year.” Lujendra Ojha, a young researcher recruited by Mr. Wray in 2012 as his first PhD student at Georgia Tech, reported “a strange new spectral signature he had isolated from the Martian dark streaks.”

“Quite coincidentally, I had just purchased a laboratory infrared spectrometer for Georgia Tech,” Mr. Wray recalls, and he and Mr. Ojha, along with Mary Beth Wilhelm, another of Mr. Wray’s PhD students, proceeded to test samples, one of which was a hydrated perchlorate. “It matched Luju’s [Mr. Ojha’s] spectrum perfectly We knew immediately that this meant liquid water, specifically briny water, was flowing down the slopes on Mars today, evaporating and leaving behind perchlorate salts.” Mr. Wray and his students collaborated on a paper that was published last month in Nature Geosciences describing this revelation.

“The discovery was exciting enough for a press release, but when NASA realized it would be published in the same week that The Martian would open in theaters, they realized the potential for reaching a broader audience and called a TV news conference.”

The modest Mr. Wray yielded center stage at the news conference to his two students. “NASA asked who from Georgia Tech should participate, and my answer was “Luju and Mary Beth.” They had led the work, and furthermore I had benefited so much from the generosity of my own mentors that I knew it was time to pay it forward and let them have the spotlight! We did not anticipate how bright that spotlight would be!”

What’s Next?

So, does this 31-year-old professor still have hopes of fulfilling his childhood dream of a journey to Mars? Mr. Wray reflected on his research team’s accomplishments so far. “I have been so encouraged by it, feeling more optimistic than I have in some time that humans will walk on Mars within the next 20 years or so. And we’ve now shown them where they can find water, a precious resource (as The Martian aptly illustrates). The dark streaks on Mars also now seem like the best places to look for habitable conditions or even life.”

Mr. Wray is currently a member of a NASA-sponsored assessment group providing input on how a future mission might better understand and characterize these seasonal wet flows. And when such missions are built and launched, Mr. Wray wants to be involved.

“I still want to go to space someday,” he stated. “Maybe just as a ‘space tourist.’ But if humans are going to Mars and back in my lifetime, then I would like to be a part of that, whether as an astronaut myself or as one of the scientists back on Earth supporting their mission.”

Local Roots

Mr. Wray, whose mother lives in Princeton and teaches drama at Princeton High School and whose father is a lawyer living in Princeton Junction, fondly recalled his education in high school at WW-PHS and at Princeton University, where he worked with Astrophysics Professor Ed Turner. Mr. Wray knew at the time that he wanted to concentrate on the solar system, “the most likely place to answer definitively the question that I found most interesting of all: Is there now, or has there ever been, life on another planet?”

Mr. Wray’s continuing curiosity next led him to Cornell, where Professor Steve Squyres was the lead scientist for two rovers that NASA had landed on Mars. Mr. Wray became his professor’s representative on the Mars Reconnaissance Orbiter science team and was able to use its observations as the basis for his doctoral dissertation on where, when, and how Mars had hosted liquid water in its distant past. He was hired as an assistant professor at Georgia Tech in 2011 after receiving his PhD from Cornell.

Mr. Wray says he visits his parents in Princeton about once a year, but he has no plans for leaving Atlanta, where he lives with his wife, Maggie, whom he met in 2002 when they were both freshmen in the astrophysics department at Princeton; they married six years later when they were both graduate students at Cornell. Mr. Wray didn’t say whether she was looking forward to accompanying him on his future travels to Mars.