On an average day, Dr. Penny Boston goes to the office underground in a dark void that could be extremely hot or extremely cold, filled with poisonous atmospheres of carbon monoxide and ammonia with sulfuric acid-filled walls and hot acid waters.

Sound like a good time? It is for one of the world’s foremost cave and karst scientists who believes the deep, foreboding caverns of Earth may be the best training grounds for human missions to Mars.

“I believe the best place to find life on Mars will be underground, not the cold, radiation-blasted deserts of the surface,” Boston says. “The Martian subsurface might have water, or it might have ecosystems as weird as the poisonous, sulfuric acid-soaked Cueva de Villa Luz caves in the Mexican state of Tabasco.”

A TED lecturer, author of 133 publications and, most recently, the star of National Geographic’s Into the Lost Crystal Caves, Boston is the Director of Cave and Karst Studies and professor of Earth and Environmental Sciences at New Mexico Tech. She is also the Associate Director of the National Cave and Karst (bedrock eaten away by water to form underground voids) Research Institute in New Mexico, a member of the SLIME team— Subsurface Life in Mineral Environments, and co-founder of the Mars Society which operates the Mars Desert Research Station in Utah constructed to simulate future human habitat on the red planet.

Called “an extremophile,” Boston has dived into hot acid waters, rappelled into deep pristine caves where no humans have gone before, explored the deepest limestone cave in the U.S., and lived for two weeks with five other “chambernauts” in the Utah desert to simulate working conditions on Mars.

Boston’s research focuses on speleology (cave science), microbial life in extreme environments, and astrobiology (the study of life in the universe). Working with many groups including the NASA-Goddard Spaceflight Center and the NASA Jet Propulsion Laboratory, she probes the intimate connection between Earth’s most challenging places and exploration of our universe.

Her cutting-edge exploits have won her the Space Foundation Award, a Fellow of the NASA Institute for Advanced Concepts, past President and founding member of the Association of Mars Explorers, and the Lifetime Achievement Award from the National Speleological Society.

But, not all of Boston’s work is out of this world. In her voyages to the center of the Earth, she studies bizarre microbial life that survives by living off organic material or literally eating rock.

“I would say that the bulk of organisms that we find are novel; they’re not known to science,” she says. “These are truly evolutionary self-contained environments. Many of them are physically isolated from the surface, little miniature planetary systems within our own crustal environment.”

Working in conditions of the crystal caves of Mexico where temperatures hit 50 degrees C (122 degrees F), and 100 percent humidity, Boston calls the adventure “the most beautiful place on Earth” and “one step away from Hell.” These magnificent caves, where scientists can only work a few minutes at a time, are criss-crossed by giant selenite crystals up to eleven meters long.

For Penny Boston, her work is down to Earth and out of this world.