Pamela Conrad wants to find signs of life in outer space.
Photo by Heather Smith / Special to The Antarctic Sun Scientists at the Battleship Promontory field camp look at the rocks they will use to test their machines. The machines look for clues of life inside rocks, and the scientists hope the instruments eventually get sent to Mars.
“I guess it comes from watching a lot of Star Trek as a kid,” said Conrad of NASA’s Jet Propulsion Lab.
Before getting to space, she’s using the McMurdo Dry Valleys as a stand-in for Mars to test machines that look for signs of life inside rocks. She and seven other scientists spent three weeks testing the machines. She hopes the machines will go to Mars.
“We’re interested in how you find evidence of the clues of life on other planets,” she said. “I would like to be able to do that without even touching the potential targets.” Conrad tested four machines. Another scientist from NASA, Robert Carlson, is the principal investigator on a similar project that was folded into Conrad’s. His group tested a fifth machine. Together, the instruments look at many components of the rocks —how they absorb light, what molecules they hold, whether they are emitting volatile organic molecules, and what types of minerals they’re made of. These factors indicate tiny organisms living inside.
Conrad’s group took a small number of rocks home to study in the lab, where they will state conclusively whether the rocks are home to living things. They will then compare their results from the machines in the field with their lab tests to see how accurate the instruments were. Their goal is to say that if all the machines show substantial signs of life within a rock, then there will be life within that rock.
Despite the popular notion, NASA isn’t truly looking for life on Mars, Conrad explained. Instead, scientists are looking for signs that the planet was ever or currently is habitable. This can be done by looking for evidence of substances, like water, which we believe are necessary to sustain life. Or it can be done by looking for clues that life existed or still exists, which is what the machines do.
Conrad’s four machines, which never touch the rocks, are run remotely from laptops. The first measures how much light is absorbed or reflected off a rock. The group wants to understand this because they believe there are subtle visual clues that the rocks have which suggest life inside.
Conrad said scientists who study rocks can tell if a certain rock is likely to be inhabited, and are often right, but they can’t articulate what it is they’re looking for. This instrument might be able to help hone in on that by picking up on visual markers that humans notice but can’t specify. The second machine sends out a laser that causes the rock to become fluorescent. The color of the rock’s fluorescence indicates what type of molecules the laser is hitting.
The third machine uses a laser as well. The laser subtly changes color depending on what minerals it hits.
The fourth machine “is basically a sniffer,” Conrad said. It has a needle that measures volatile organic molecules in the air around the rock. These are molecules that might be given off by organisms in the rock as they go through their normal life cycle.
Carlson tested a fifth machine. It uses an infrared spectrometer to identify the molecules in the rock. He and his team are interested in particular in how iron is distributed through the different layers in the rock.
Desert rocks have iron spread across their surface, he said. His team’s theory is that organisms in the rock, like lichen, dissolve a small amount of the iron on the surface. They do this to get enough sunlight to photosynthesize, but not too much so that they are vulnerable to ultraviolet rays. The dissolved iron accumulates lower down in the rock. His machine will look specifically at the factors involved in this process, like organic acids used to dissolve iron.
It is hard to imagine how rocks end up like this — with the heavier layers of iron sitting on top of the lighter ones — without help from life inside the rocks, explained Henry Sun of the Desert
Research Institute in Las Vegas, who is working with Carlson. The eight scientists spent three weeks in the field so they could test the instruments under different environmental conditions to see if temperature or sunlight affect the results.
They chose their location at Battleship Promontory because a large amount of organisms live in the rocks there. Conrad said that if the machines don’t work in a place where they have a high chance of finding something, then they certainly won’t work somewhere where the odds are slimmer.
The trip to the Dry Valleys is the culmination of Conrad’s three-year project. Her group has tested its machines already with good results in Death Valley and in the Arctic.
Carlson, who is in the first year of his two-year project, joked about the extent of his field testing.
“We’ve gone as far as the JPL parking lot,” he said, and has pictures to prove that the group tested the machine on a large rock in the driveway of the Jet Propulsion Lab.
Both groups applied to get their instruments on a 2009 expedition to Mars, but they weren’t accepted. The scientists plan to keep trying to get them to Mars. In the meantime, the group will continue testing and perfecting the machines.
Battleship Promontory was included in the new Dry Valleys Antarctic Specially Managed Area plan, adopted last year. This means increased restrictions in terms of the work that can be done there in hopes of limiting the human impact on the area. Conrad said this makes it an even more appropriate place to test machines that aren’t invasive and won’t disturb the rocks.
“If you could point to a rock and say there’s life in that rock, that would be awesome because you wouldn’t have to break open that rock,” she said. “The longer you can sustain it without doing something to it, the longer it will be there for someone else to study.”
The project is funded by NASA with support from the NSF: Pamela Conrad, NASA Jet Propulsion Lab.
