Journey to the bottom of the world

Antarctica is known as a desolate landscape of winds that roam a continent of snow and ice. What is less known about these winds, however, is that over countless years they uncover rocks cradled by the blue hue of ice fields. Like an anthropologist gently uncovering dirt from ancient objects, the winds soar across the snow towards the mountains at such an angle that they take with them fragments of snow and ice, but leave denser rocks in their wake. Upon first glance, these rocks might not seem any different than a common terrestrial sample shed off the nearby mountains, but the experienced eye can decipher a melted outer crust, signifying the rock has come searing through the atmosphere.

In this backdrop of white, the human eye is well suited to finding and discovering the meteorites that land there. Meteorites fall from asteroids like Vesta, from the moon and from Mars. Rather than having to put forth the expense into going out into our solar system to collect these precious samples, they come knocking upon Earth’s doorstep.

A collaboration between NASA, the National Science Foundation and the Smithsonian Institute sponsors the Antarctic Search for Meteorites (ANSMET)—a team of Antarctic explorers has traveled to bring these meteorites home to the Astromaterials Research and Exploration Science (ARES) Division at NASA’s Johnson Space Center since the mid ‘70s. In fact, this year marks the 40^th season of ANSMET.

The ANSMET field teams are made up of six to 10 team members who are sent to Antarctica for eight to 10 weeks. A typical field season collects hundreds of new meteorites, and the samples from this season will arrive at Johnson in the spring, having been sent frozen by ship and truck.

Building 31 at Johnson is home to the Meteorite Processing Lab, where these samples will be welcomed and curated, undergoing analysis for characterization in preparation for their study by scientists within ARES as well as around the world. Some ARES scientists even dare to leave their labs behind and travel into the cold that awaits them at the bottom of the world.

One of these cold-adapted explorers is Planetary Scientist David Mittlefehldt, known less formally as “Duck.” Mittlefehldt is also a geologist and geochemist in ARES at Johnson. He divides his time between pursuing research on the formation of meteorites and the geology and geochemistry of Mars. His studies use data from both meteorites and robotics like the Mars Exploration Rover to shed light on the early history of the solar system. 
 
 Mittlefehldt grew up in western New York and, as a child, was always inclined toward math, science and field exploration. When Mittlefehldt first began school at the State University of New York at Buffalo, his goal was to become a student of paleoanthropology, the branch of anthropology concerned with early human fossils. Prepared to be both creative and practical in his approach to the study of ancestral fossils, he turned toward geology. In his first year at college, the protests and heightened college security of the Vietnam War made him decide to transfer to the State University of New York College at Fredonia, where he received his bachelor’s degree in geology. In 1978, he went on to receive his doctorate in geochemistry from the University of California at Los Angeles, and it was during this time he began to specialize in meteorites. Mittlefehldt continued post-doctorate work at the University of Arizona and went on to “happily bang rocks” for the Weizmann Institute of Science in Rehovot, Israel. Due to his specialization in geochemistry and meteorites, he was recruited by NASA in the fall of 1985.
 
Working in the hostile Antarctic environment would not be what anyone would consider a walk in the park, but then, Mittlefehldt is not your average planetary scientist. He will be returning to Antarctica for his fifth mission with the ANSMET team.
 

“I am not sure I would call any of it a challenge,” Mittlefehldt said. “Winter was always my favorite season in western New York. On weekends, my brothers and I would spend all day out in the woods playing, returning home at suppertime with our clothes literally frozen stiff.”

He explained that some trials in life are “meant to be endured” and, in fact, “eight hours a day, seven days a week out on a snowmobile in the bone-chilling winds of Antarctica is much easier, and safer, than navigating Houston traffic.”

Mittlefehldt’s wide range of experiences have greatly contributed to NASA’s current understanding of the geology and geochemistry of both asteroids and larger planetary bodies like Mars. In 1994, he came across a rock that was “puzzling.” Upon further study and contemplation, he realized that the data he had collected was simply inconsistent with the rock’s classification. His findings confirmed that the meteorite was, in fact, not a meteorite from Vesta, but a sample from Mars. His research was confirmed when other types of analyses displayed all the hallmarks of Martian meteorites.
 

“The most essential skill of a scientist is to keep an open mind while focusing on expanding one’s practice into a wider range of experiences,” Mittlefehldt said. “In the episode with meteorite ALH 84001, my mind was ready to let the data tell me the story rather than try to force the data into the narrative of the rock.”

 

Mittlefehldt has also been a part of groundbreaking studies that recorded the interaction of fluids with rocks on Mars, confirming that there had been—at one time in its history—water on this planetary body. These findings have contributed greatly to our current scientific understanding of the Red Planet and will someday assist in a human expedition.

 

To all who might try to reach him in the coming months … they will receive this automatic message.

 

“I have fled the US for points south. I will be in Antarctica until the end of the year. My inbox will fill up, and I will delete mercilessly when I return. You *might* want to send me a follow-up message in January.”

 

Mittlefehldt has not only the mind of a scientist, but also the eyes of an explorer. Each day he brings to his work a sense of joy and fascination that will keep him warm in the land of the snow and ice.

 

 

Melanie Whiting

NASA Johnson Space Center