Searching for Hints of Extra-Terrestrial Life in the Hard Rock of Earth

Searching for Hints of Extra-Terrestrial Life in the Hard Rock of Earth

NASA scientist Amy McAdam aims the XRF at a sample in Kilbourne Hole. (Photo: Katherine Wright)

By Kayla McKiski

Kelsey Young and Amy McAdam, research scientists from NASA, kneel in the desert, pointing their guns at the rock samples below them. Their instruments, which determine the elemental composition of a geological site, may be used by astronauts someday to look for clues of life on other planets.

NASA scientist Kelsey Young fires the XRF on a sample at Kilbourne Hole. (Photo: Katherine Wright)
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“The big question for planetary scientists is: Does life exist out there, somewhere, outside our planet? Did it once? Could it one day?” Young said.

The two complementary geochemical tools use x-ray fluorescence (XRF) and laser-induced breakdown spectroscopy (LIBS) to find and analyze the overall composition of a small area. The XRF can detect elements that are heavier than magnesium and the LIBS can identify smaller elements such as carbon and oxygen. Researchers hope to be able to correlate specific sets and quantities of elements with indications of life forms.

“While the XRF and LIBS would never be able to directly detect organic matter or any signs of life, they could detect life-related chemistry,” Young said. “We as a science community need to figure out, when there is ‘this’ type of life, ‘these’ chemical conditions might be found.”

Astronauts Jack Schmitt (left) and Butch Wilmore get a close look at the XRF device in action. (Photo: Elizabeth Bass)
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At Kilbourne Hole, astronaut Barry “Butch” Wilmore and geologist Elizabeth Rampe chose sample spots for the operators to use the instruments during extravehicular activity (EVA) simulations. In the future, astronauts on actual missions could operate similar tools and call the shots on-site, making decisions about whether an area should be explored based on the data and knowledge gained from field research like the RIS4E work in New Mexico.

Though they are still early in their development for use on missions to space, the XRF and LIBS instruments can still provide precursors to the clues NASA’s planetary scientists are searching for.

“You can use the instruments together to understand how the environments have changed or what the environmental conditions were like at one point in time,” McAdam said. “I consider the geochemical instruments to be useful for figuring out which rocks were put down when and which rocks preserve environments where life is most likely to have been.”

For example, layers with a high concentration of clay minerals would indicate that water was around. Layers with an abundance of carbon, which can be further categorized by isotope—different atomic forms of the same element— would indicate the presence of organic molecules.

“If you had a bunch of carbon and it didn’t seem obviously mineral, then that would be highly suggestive [of life],” McAdam said. “The main role is to support the next step of an analysis looking for organic molecules or maybe isotope indications that there was life present.”

While it’s a novel idea to send astronauts into space with geochemical analysis tools to hypothesize life, the concept behind the XRF and LIBS is not. Comparable instruments are stationed on the Curiosity rover, a car-sized robot exploring Gale Crater on Mars. The rover is equipped with a suite of sensing instruments called the Chemistry and Camera complex, or ChemCam, which is similar to LIBS. Also onboard is an alpha particle x-ray spectrometer (APXS), whose function is like that of XRF.

“In the case of Curiosity, there have been mostly sedimentary rocks, so if you gauge when the rocks were laid down, it can give you ideas on the habitable potential,” McAdam said, referring to the rover’s ability to discover precursors to life.

Comparable Instruments could someday be the handheld machinery that finds the bread-crumb trail leading to the answer to one of the greatest questions on earth: Are we alone in this vast universe?

NASA scientist Amy McAdam aims the XRF at a sample in Kilbourne Hole. (Photo: Katherine Wright)

By Kayla McKiski

Kelsey Young and Amy McAdam, research scientists from NASA, kneel in the desert, pointing their guns at the rock samples below them. Their instruments, which determine the elemental composition of a geological site, may be used by astronauts someday to look for clues of life on other planets.

NASA scientist Kelsey Young fires the XRF on a sample at Kilbourne Hole. (Photo: Katherine Wright)
CLICK PHOTO TO ENLARGE

“The big question for planetary scientists is: Does life exist out there, somewhere, outside our planet? Did it once? Could it one day?” Young said.

The two complementary geochemical tools use x-ray fluorescence (XRF) and laser-induced breakdown spectroscopy (LIBS) to find and analyze the overall composition of a small area. The XRF can detect elements that are heavier than magnesium and the LIBS can identify smaller elements such as carbon and oxygen. Researchers hope to be able to correlate specific sets and quantities of elements with indications of life forms.

“While the XRF and LIBS would never be able to directly detect organic matter or any signs of life, they could detect life-related chemistry,” Young said. “We as a science community need to figure out, when there is ‘this’ type of life, ‘these’ chemical conditions might be found.”

Astronauts Jack Schmitt (left) and Butch Wilmore get a close look at the XRF device in action. (Photo: Elizabeth Bass)
CLICK PHOTO TO ENLARGE

At Kilbourne Hole, astronaut Barry “Butch” Wilmore and geologist Elizabeth Rampe chose sample spots for the operators to use the instruments during extravehicular activity (EVA) simulations. In the future, astronauts on actual missions could operate similar tools and call the shots on-site, making decisions about whether an area should be explored based on the data and knowledge gained from field research like the RIS4E work in New Mexico.

Though they are still early in their development for use on missions to space, the XRF and LIBS instruments can still provide precursors to the clues NASA’s planetary scientists are searching for.

“You can use the instruments together to understand how the environments have changed or what the environmental conditions were like at one point in time,” McAdam said. “I consider the geochemical instruments to be useful for figuring out which rocks were put down when and which rocks preserve environments where life is most likely to have been.”

For example, layers with a high concentration of clay minerals would indicate that water was around. Layers with an abundance of carbon, which can be further categorized by isotope—different atomic forms of the same element— would indicate the presence of organic molecules.

“If you had a bunch of carbon and it didn’t seem obviously mineral, then that would be highly suggestive [of life],” McAdam said. “The main role is to support the next step of an analysis looking for organic molecules or maybe isotope indications that there was life present.”

While it’s a novel idea to send astronauts into space with geochemical analysis tools to hypothesize life, the concept behind the XRF and LIBS is not. Comparable instruments are stationed on the Curiosity rover, a car-sized robot exploring Gale Crater on Mars. The rover is equipped with a suite of sensing instruments called the Chemistry and Camera complex, or ChemCam, which is similar to LIBS. Also onboard is an alpha particle x-ray spectrometer (APXS), whose function is like that of XRF.

“In the case of Curiosity, there have been mostly sedimentary rocks, so if you gauge when the rocks were laid down, it can give you ideas on the habitable potential,” McAdam said, referring to the rover’s ability to discover precursors to life.

Comparable Instruments could someday be the handheld machinery that finds the bread-crumb trail leading to the answer to one of the greatest questions on earth: Are we alone in this vast universe?