“Sirens of Mars”: Coming of age on the red planet

In the winter of 2004, Sarah Stewart Johnson, then a graduate student at the Massachusetts Institute of Technology, was on a field trip in the desert east of California’s Sierra Nevada. While learning to map geological terrains, she fell prey to an adolescent thrill. Boulders were perched on ledges; when nobody was watching, she would strain and push one over the edge just to watch it roll hundreds of feet, crash and break apart.

“It was just the power of it,” she said recently in an interview. “It would just echo up through that emptiness. The dust would come up and the boulder would clang into the rocks as it barreled down.”

The anecdote is one of many that Johnson, 41, relates in her first book, “The Sirens of Mars: Searching for Life on Another World,” which was published earlier this month. Part history, part science lesson and part memoir, the book is full of inside stories about the quest to find life, or something, on Mars, a planet we have been invading ever since the Space Age began.

“Mars has been our mirror, our foil, a telltale reflection of what has been deepest in our hearts,” Johnson writes in the book’s forward. “We have seen in Mars a utopia. A wilderness. A sanctuary. An oracle. With so few landmarks, guideposts, or constraints, all is possible; without data that could be used to cabin our inquiry or limit our imagination, Mars has been a blank canvas. And tenderly, our human seeking has rushed to fill it.”

The book is also a comingof-age story for Johnson and a new generation of planetary explorers. In the next half-century, their machines are likely to determine whether anything like life as we know it resides elsewhere in the solar system.

At Georgetown University,

Johnson runs her own lab, which studies old rocks for signs of ancient exotic life of the sort that might be found on Mars or some other extreme world.

The lab’s website is festooned with pictures of her and colleagues combing the rocks and sands in Antarctica, Australia and the Atacama Desert in Chile, for signs of ancient life. She is also a visiting scientist at NASA’S Goddard Space Flight Center, where she is part of a team working with Curiosity, NASA’S older rover now climbing a mountain in a crater on Mars. And she hopes one day to be analyzing rocks returned from Mars in her lab.

Reached over Zoom in Kentucky, where she was visiting family, Johnson radiated an easy, unflappable manner. She responded to questions with a wide smile, as if the light had just broken on her face, and a drawn-out “Yeah” as she mulled her answers.

In “Sirens of Mars,” Johnson chronicles the personalities, the surprises, the dashed expectations and the claims — made and abandoned — of the discovery of life on Mars. It’s also a personal chronicle; the due date for her first pregnancy, in August 2012, coincided with the landing of the Curiosity rover on Mars, temporarily derailing her chances of participating in what was the biggest Mars mission yet. She watched her colleagues at the Jet Propulsion Laboratory on television, saddened that Mars might be slipping away.

“Opportunities only come around so often,” she writes. “The planets aligned and then swung apart.”

She had not set out to make herself a character in the book, she said. The project began with the habit of writing down poignant and evocative things that would never make it into scientific journals, and grew from there.

Johnson grew up in Lexington, Ky., watching “Cosmos” with her father, a lab technician who was a geology and astronomy enthusiast. Her mother had been a teacher but stopped when her older sister, Emily, was born with Down syndrome. Johnson recalls her father dragging her and Emily to look at the exposed strata in road cuts.

“There was a point I remember when I was young where I just felt. like, Oh, this is so nerdy,” Johnson recalled.

She found her calling when she discovered a tiny fern underneath a rock on the barren slopes of Mauna Kea during a geology field trip.

“I suddenly saw something I might haunt the stratosphere for, something for which I’d fall into the sea,” she writes. “Not fame or glory or a sense of adventure, but a chance to discover the smallest breath in the deepest night and, in so doing, vanquish the void that lurked between human existence and all else in the cosmos.”

The work happily takes her to extreme corners of the world — deserts in Chile, Australia, Iceland and Antarctica — in search of improbable forms of life that have survived the kinds of circumstances that prevail on Mars and elsewhere out there. “Fieldwork is always tremendously exciting,” she said. “I mean, just to be at the edge of the world; it really does feel sometimes like you’re on another planet.”

Her proxy rockhound, the robot Perseverance, was launched toward Mars on July 30 as the flagship of this year’s flotilla. If it lands safely this winter, its mission is to procure Martian rocks and store them for return to Earth later this decade. Johnson hopes that her lab will be among those given samples to scour for evidence of ancient life.