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June 11, 2014

Geologist Enjoys a Pas de Deux with the Planets

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Brett Denevi at Convict Lake in California, studying silicic volcanism with colleagues from the Lunar Reconnaissance Orbiter Camera team.
Credit: JHU/APL

Brett Denevi, a planetary geologist at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Md., says she has always loved space, but initially in an abstract way. “In college I thought about studying physics and astronomy, but when I explained to my physics advisor the vague ideas I had about what I wanted to do, he suggested I talk to people in the geology department.”

She did just that, and she landed a research job helping make image mosaics for the Near Earth Asteroid Rendezvous mission to the asteroid Eros. “I learned about doing planetary geology as a career, and I was set. I loved working on an active mission, and because I had always loved photography, working with image data was perfect. As I started taking geology classes it all came together.”

Denevi, the Deputy Instrument Scientist for the Mercury Dual Imaging System (MDIS) on the MESSENGER spacecraft, became involved with the MESSENGER mission when she was at Arizona State University. “I had just started as a post-doc there shortly before MESSENGER’s first flyby of Mercury in January of 2008,” she explains. “I had been working with Mariner 10 images of Mercury, so I was really lucky that the timing worked out so well for me to start working on MESSENGER.”

She started out on the mission as an “unofficial” science team member, working as a post-doc on her own studies, and helping with calibration tasks as needed. Eventually, she was given roles of increasing responsibility.

As the MDIS Deputy, Denevi reviews and plans image sequences to make sure the team is getting the highest-quality images and the most important images of Mercury. “We spend a lot of time prioritizing between color versus monochrome, and high resolution versus broad coverage, because there are more opportunities for images than we could possibly ever actually acquire,” she says. She also spends considerable time on image calibration, so that when scientists use the images for their investigations, they can switch from raw data numbers to meaningful values, such as the percent of light the surface is reflecting.

She fills another role on MESSENGER, as the Deputy Chair of the Geology Discipline Group, managing the scientists who focus on Mercury’s geology. “There is an administrative component; I help to organize science team meetings, summarize findings from our group and help move manuscripts along toward publication,” she said. “But as part of the science team I also get to focus on my own science. I’m really interested in the history of volcanism on Mercury, so I map out volcanic deposits and interpret what the role of volcanism was in shaping Mercury’s geologic history and crustal evolution.”

In her years on the mission, one of her most memorable moments was from MESSENGER’s first flyby of Mercury. “We were waiting for the first data to be downlinked in the old Science Operations Center (SOC), but another spacecraft had an emergency and was given priority on the Deep Space Network,” she recalls. “This meant our data would be delayed; but we were told we could downlink one image early. Waiting for this one image, most of which covered the side of Mercury that had never been seen before, was really exciting.”

“When it finally came down and we pulled it up on the screen in the SOC, it was really amazing,” she says. “There was Caloris, and its volcanic deposits looked nothing like equivalent lunar deposits; they were brighter than the surrounding terrain. We all spent quite a while marveling over that one image, until later the rest of the data poured down and we worked long hours trying to make sense of it.”

Denevi is also a co-investigator on the Lunar Reconnaissance Orbiter Camera, and a participating scientist on the Dawn mission to the asteroid Vesta. “My experiences with all of these missions have been incredible,” she says. “But I think overall less was known about Mercury than about either the Moon or Vesta, so it’s been really fun being involved in the real sense of discovery that comes with studying Mercury.”

When she’s not pouring over images from Mercury, Denevi is perfecting her pliés, relevés and sautés at the Maryland Youth Ballet. Interestingly, her two passions — dance and planetary science — converged. The International Astronomical Union dictates that all craters on Mercury be named after famous figures in the arts. Before Denevi’s arrival at APL, in 2010, not one crater out of hundreds had been named after a dancer or a choreographer. Thanks, in part, to Denevi’s advocacy, there are now craters named after Alvin Ailey, George Balanchine, Margot Fonteyn, Rudolf Nureyev and Marius Petipa.

“The crater Balanchine is my favorite,” she says, “because the blue rays extending from the crater remind me of the long, blue tutus in his classic ballet, ‘Serenade.’”

Media contact: Paulette Campbell, 240-228-6792, Paulette.Campbell@jhuapl.edu