Searching for Life

Searching for Signs of Ancient Life on Mars

STORY BY ARTHUR FOULKES

to get to the bottom of a mystery, the great detective Sherlock

Holmes often fixed his eyes close to the ground to carefully examine a fresh crime scene in search of the most minute-sized clues. Within the next year, a scientific instrument designed by NASA, named SHERLOC, will be doing the same thing on Mars, thanks to the work of 2000 applied optics alumnus Brian Monacelli and a team of engineers and scientists at the space agency’s Jet Propulsion Laboratory (JPL) in California. Only instead of solving some Earth-bound mystery, this SHERLOC will be trying to answer the question: Billions of years ago, was there life on Mars? SHERLOC stands for Scanning Habitable Environments with Raman and Luminescence for Organics and

Chemicals–a true mouthful. The instrument, a spectrometer, will use sophisticated optical devices, including an ultraviolet laser that fluoresces chemicals, to scan the surface and near-subsurface of Mars in search of organic and chemical evidence that life ever existed on the Red Planet. “It will be looking for chemicals that are indicative of life,” says Monacelli, a five-year veteran of NASA’s Mars 2020 mission team. He was responsible for alignment and testing of SHERLOC’s optical systems. SHERLOC will be mounted at the end of a robotic arm attached to Perseverance, the remote-controlled six-wheel Mars 2020 rover, which engineers and scientists will direct from millions of miles away through the Deep Space Network from NASA facilities on Earth.

Applied optics alumnus Brian Monacelli is part of the NASA team that developed the SHERLOC project to search for signs of ancient Martian life through the Mars 2020 mission. He showed Rose-Hulman students a model of the device and discussed his career with NASA during a campus visit.

sherloc (watson)

The optical instrument will not actually touch the surface of Mars but will closely observe it through a magnifying lens about two inches from the dusty ground. And, like the fictional Sherlock Holmes, the device will be assisted by Watson, the name NASA gave the rover’s main turret-mounted camera. It will provide a wide-angle view to compliment the much more tightly focused view from SHERLOC’s camera. One challenge of the SHERLOC project was to make sure Mars 2020 doesn’t accidentally carry microbial life from Earth to the Martian surface,

Monacelli says. He adds that any contaminants would corrupt the science by adding a background signal. That’s why construction of SHERLOC and the rest of the mission’s equipment has been conducted in a cleanroom setting.

“SHERLOC is one of the cleanest instruments JPL has built. We want to measure for signs of Martian life, not for signs that we had pizza for lunch when we aligned its optics,” he says.

The Mars 2020 mission is set for liftoff this summer from Cape Canaveral in Florida. It is scheduled to touch down in Jezero Crater on Mars in February 2021. n

Scratching Surface of Exploring Mars The Mars 2020 Perseverance rover mission is part of NASA’s Mars Exploration Program, a long-term effort of robotic exploration of the planet. The Mars 2020 mission addresses high-priority science goals for Mars exploration, including key astrobiology questions about the potential for life on Mars. The mission takes the next step by not only seeking signs of habitable conditions on Mars in the ancient past, but also searching for signs of past microbial life itself. The Perseverance rover introduces a drill that can collect core samples of the most promising rocks and soils and set them aside in a “cache” on the surface of Mars. A future mission could potentially return these samples to Earth for study by scientists. The mission also provides opportunities to gather knowledge and demonstrate technologies that address the challenges of future human expeditions of Mars. These include testing a method for producing oxygen from the Martian atmosphere, identifying other resources (such as subsurface water), and characterizing weather, dust, and other potential environmental conditions that could affect future astronauts living and working on Mars. —Courtesy NASA