Spectroscopy, Cameras to Help Explore the Red Planet

Sarina Tracy, sarina.tracy@photonics.com

When author H.G. Wells wrote his two-volume The Outline of History in 1920, his eyes turned upward, once again, toward space. “Life,” he wrote, “for ever dying to be born afresh, for ever young and eager, will presently stand upon this earth as upon a footstool, and stretch out its realm amidst the stars.”

He couldn’t have been more right. And in 2020, a few photonic technologies will do the same.

NASA’s Mars 2020 Rover will house sophisticated hardware, along with upgraded imaging and spectroscopy equipment, during its exploration of the Red Planet. The mission is threefold: to geologically assess the rover’s landing site, to search for signs of ancient Martian life, and to determine the potential habitability of the environment by collecting soil samples in a canister for a potential return to Earth.

Photo courtesy of NASA.

“There is such strong public interest in learning more about the kinds of places that people are going to visit one day,” said planetary science professor Dr. Jim Bell of Arizona State University. Bell and his team will provide the Mastcam-Z camera system with panoramic, stereoscopic imaging and 3.6:1 zoom capability. It will comprise two zoom cameras to provide broadband RGB color imaging and narrowband multispectral capability from the visible to the short-wave IR wavelengths. The Mastcam-Z will be the rover’s “main eyes,” assisting with operations and mineralogy of the planet’s surface.

“We’ve selected our filters to maximize our ability to detect certain kinds of iron-bearing silicates, oxides and hydroxides,” Bell said. “There will literally be millions of targets to choose from, so the imaging sweep across the landscape, in color, will help narrow that down to a smaller, more manageable number.”

Los Alamos National Laboratory in New Mexico, led by Dr. Roger Wiens, will provide the SuperCam, an imaging instrument that combines laser-induced breakdown spectroscopy, Raman and time-resolved fluorescence spectroscopy, passive VISIR spectroscopy and high-resolution color imaging for elemental composition and mineral identification. The time-resolved fluorescence can resolve organically produced fluorescence created by inorganic sources, while Raman spectroscopy provides identification of many organic molecules. The SuperCam can also dust off surfaces with laser blasts.

“The elemental and mineral compositions are highly complementary and lead to a much greater understanding of the provenance of a sample than if we just had one or the other,” Wiens said.

NASA chose seven instruments from 58 proposals, with development costs estimated at $130 million. The other devices include a UV spectrometer to detect carbon molecules and aqueous environments; an x-ray lithochemistry fluorescence spectrometer to determine elemental composition; a set of sensors that measure temperature, wind speed, pressure and relative humidity; and a ground-penetrating radar imager that explores the geological structure of the subsurface. The rover will also work to produce oxygen from Martian carbon dioxide, which could be useful in providing an oxidizer for a future Mars ascent vehicle.

“People will go back to the moon, to asteroids and eventually Mars and its moons for science, tourism and eventually colonization,” Bell said. “Those visits are likely many decades, perhaps centuries, away, but it’s exciting that the groundwork for those adventures is starting now, within the active robotic exploration of our solar system.”