Engineers from the US National Aeronautics and Space Administration (NASA) recently visited lava tubes in the North East of California to test a rover that could be used to search for underground life on other planet, the agency said on 26 June.
Scientists predict that there are caves – known as lava tubes – beneath the surfaces of the Moon, Mars and Venus that are formed by flowing magma and covered in tiny crystals, and which could potentially host living organisms.
These lava tubes can stretch for miles. On other planets with less gravity, some caves could even be large enough to fit small cities. For places like Mars too dry for life and with atmospheres too thin to block dangerous space radiation, lava tubes could safely harbor potential life.
Beyond helping us pinpoint the best spots to search for life, these caves could bring us one step closer to a permanent presence on the Moon and safe exploration at Mars – the ultimate goal of NASA’s Artemis program.
On Earth, similar caves are home to complex ecosystems, all supported by microbes that “eat” rocks, converting them into energy for life. The scientists of the BRAILLE project believe such life could exist – or have once existed – in the caves of Mars as well.
Operated out of NASA’s Ames Research Center in Silicon Valley, the Biologic and Resource Analog Investigations in Low Light Environments (BRAILLE) team is developing the capability to detect life on the walls of volcanic caves from afar by venturing into North America’s largest network of lava tubes, with the goal of advancing efforts to search for life elsewhere in the universe.
Already, data from the team’s first field deployment is helping scientists understand the interactions between biology and geology in these volcanic caves. New science from the project will be presented this week at the Astrobiology Science Conference in Seattle.
“We don’t think there’s life to find on the Moon now, but some day the life on the Moon might be us,” Jennifer Blank, the principal investigator for the BRAILLE project, said in a statement. “And if I were going to the Moon, I’d want to go to a lava tube.”
“Orbital satellite data suggests that there are a lot of these lava tubes on Mars,” she added. “If there is life there, those tubes are a good place to look. And if there was life in Mars’ ancient past, that’s where it’s most likely to be preserved.”
The BRAILLE team made its first descent at Valentine Cave, one of over 750 at the Lava Beds National Monument in California, close to the state’s northern border. According to NASA, smooth walls around 15 feet high and walkways up to 70 feet wide make it a practical place to drive a rover, and its well preserved lava flow features are similar to what the agency expects to find inside Martian lava caves.
With the right lighting, the cave’s layers of microbial material and mineral deposits create a dazzling array of colors but NASA’s cave rover – CaveR – can do even more with its scientific cameras and imaging tools.
These instruments take in small amounts of light that reflect off the cave wall’s surface, allowing scientists to identify chemical components that reveal signs of life. The rover also uses a laser scanner to map the subterranean caves.
BRAILLE’s three-week deployment involved sample collection from nine different caves, tackling scientific questions ranging from geochemistry to DNA sequencing. One result of this study is a working theory that the team calls the “Micro-Mineral Continuum,” describing how past and present microbial life appears in the caves.
Between two endpoints on this spectrum – from the walls being visibly bare rock to coated with colored films of microscopic life – are a range of different features, textures and secondary minerals created by the interactions of those microbes with the basaltic rock and water that drips down into the caves.
By studying the continuum further in future returns to Lava Beds and understanding the interplay between geology and biology in these caves, scientists will be able to know what they’re looking at when we one day send rovers to Martian caves.