Is there life in the Martian caves?
It’s a good question, but it’s not the right question, yet. An international collaboration of scientists led by NAU researcher Jut Wynne has dozens of questions we need to ask and answer. Once we figure out how to study caves on the Moon, Mars, and other planetary bodies, we can return to that question.
Wynne, a research assistant professor of cave ecology, is lead author of two related studies, both published in a special collection of articles on planetary caves by the Geophysical Research Journal-Planets. First, “Fundamental science and engineering questions in planetary cave research”, was conducted by an interdisciplinary team of 31 scientists, engineers and astronauts who produced a list of 198 questions that they, working with 82 other space and cave scientists and engineers, narrowed down to the 53 most important. Drawing on the knowledge of a considerable swath of the space science community, this work is the first study designed to identify research and engineering priorities to advance the study of planetary caves. The team hopes that their work will inform what will ultimately be needed to support robotic and human missions to a planetary cave, that is, on the Moon and/or Mars.
The second, “Planetary Caves: A View of the Solar System of Products and Processes”, was born from the first study. Wynne realized that no effort had been made to catalog planetary caves throughout the solar system, which is another important piece of the overall puzzle. He assembled another team of planetary scientists to address that question.
“With the necessary financial investment and institutional support, the research and technological development required to achieve these necessary advances over the next decade is achievable,” Wynne said. “We now have what I hope will become two seminal papers that will help propel planetary cave research from a contemplative armchair exercise to robots exploring planetary subsurfaces.”
What we know about alien caves
There are many of them. Scientists have identified at least 3,545 potential caves on 11 different moons and planets throughout the solar system, including the Moon, Mars, and the moons of Jupiter and Saturn. Caving processes have even been identified in comets and asteroids. If the surrounding environment allows access to the subsurface, that presents an opportunity for scientific discovery that has never been available before.
The discoveries in these caves could be massive. The caves may one day allow scientists to “peer into the depths” of these rocky, icy bodies, which will provide information about how they formed (but may also provide more information about how Earth formed). They could also, of course, keep secrets from life.
“Caves on many planetary surfaces represent one of the best environments to search for evidence of extinct or perhaps extant life forms,” Wynne said. “For example, since Martian caves are shielded from deadly surface radiation and violent wind storms, they are more likely to display a more constant temperature regime compared to the surface, and some may even contain water ice. This makes caves on Mars one of the most important exploration targets in the search for life.”
And it’s not just about finding life: These same factors make caves good places for astronaut shelters on Mars and the Moon when crewed missions can explore.
“Radiation shielding will be essential for human exploration of the Moon and Mars,” said Leroy Chiao, a retired astronaut, former commander of the International Space Station and co-author of the first paper. “A possible solution is to use caves for this purpose. Requirements for astronaut habitats, suits and EVA equipment must take into account exploration and cave development, for protection against both solar and galactic cosmic radiation.”
What Earth can tell us about other planets
Wynne, whose primary research is in terrestrial caves, said planetary cave research has long been a parallel research question to the terrestrial variety for nearly two decades. Caves support unique ecosystems that are sometimes quite separate from the surface ecosystem in the same area. Who’s to say that a cave on the Moon or Mars wouldn’t be similar? So many questions that he has investigated about caves on Earth, he wonders how it might apply to other planets.
He’s not the only one making the connection. Wynne has done multiple research projects with NASA to help advance sensing technologies, and his modeling of cave habitats doesn’t care much whether a cave is terrestrial or extraterrestrial. There are enough similarities in the cave environment to make reasonable predictions that they will be a major factor in the selection of cave targets for exploration.
“Deep telluric caves are often characterized by total darkness, a stable temperature approaching the average annual surface temperature, little or no air.
flow and an atmosphere almost saturated with water,” he said. “Caves on other planetary bodies are likely to exhibit similar environmental conditions, but they will also be influenced by the surface conditions of the planetary body and the internal structure of the cave.”
Keith Cowing, editor of SpaceRef.comYNASAWatch.comHe said that using the existing infrastructure on the surface and underground of a planet can help humans reach other planets sooner than if we had to take everything we needed to survive with us.
“Humans have been living in caves for hundreds of thousands of years. Then they built their own when none were available,” he said. “As such, it is natural to assume that the caves will offer similar utility as humanity expands to other worlds. While planet-wide terraforming may be an ultimate goal, using large pre-existing structures such as caves and lava tubes may be a more practical way of pushing technology to the maturity needed to tackle the surface of an entire planet. “.
Where we are now
While much of this research is prospective, it is also necessary to consider what resources, research, and support currently exist. Numerous robotic platforms and instrumentation packages are being tested, but the stumbling block comes where it so often occurs: lack of funding. With enough support, a robotic exploration mission to a lunar or martian cave could be possible in the next five to 10 years.
This research builds on previous work to form a kind of roadmap moving forward; Wynne sees it as a to-do list for that very process. The questions answered by the scientists and engineers identify the tasks needed to prepare for that robotic exploration; it also looks further ahead to the necessary advances in spacesuit technology, habitation modules, and hardware that will allow humans to live and work safely underground on the Moon and Mars.
“This is an untapped research area in planetary science, and its importance in the search for life should not be overlooked,” he said. “In our lifetime, we may well look into the interior of Mars to address the age-old question: ‘Is there life beyond Earth?'”
Heidi Toth | UAN Communications
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