Many in Mars exploration circles see Valles Marineris as a “tell-all” site, ripe for human exploration that could reveal the planet’s history and its capacity to sustain microbial life.
That said, how best to investigate the multifaceted geology evidenced at this site? Can future crews on the Red Planet safely dive into this vast canyon system? And what awaits those who explore a vast area that has been labeled the Grand Canyon of Mars?
Valles Marineris is a huge draw; a system of canyons that cut across the Martian surface that extends over 2,500 miles (4,000 kilometers), covering about one-fifth of Mars’ circumference. At some points, this colossal canyon is 200 km wide. In certain places, the canyon floor reaches a depth of 8 km.
Bottom line: it’s far deeper than Earth’s Grand Canyon.
Related: Glaciers on Mars Probably Helped Carve Red Planet’s ‘Grand Canyon’
To encourage human studies at the site of Valles Marineris, some researchers have identified and tentatively named an area known as the “Noctic Landing” site. Its strategic location allows the shortest possible surface excursions to the Martian volcanic plateau of Tharsis as well as the Valles Marineris – the magnificent feature and region on the Red Planet that reveals the longest overview of Mars’ geology and evolution through time.
Tharsis is the area on Mars that has experienced the longest and most extensive volcanic history, and may still be volcanically active. Some of the youngest lava flows on Mars have been identified on the western flanks of the Tharsis Bulge.
Furthermore, these currents are within range of future pressurized rover traverses.
High priority science
“I think that when it comes to planning human missions to Mars, we may be past the point of just thinking about imaginary science goals in location-agnostic ways,” said Pascal Lee, a planetary scientist at NASA’s Ames Research Center in California and the SETI Institute.
Lee is chairman of the Mars Institute, an international, non-governmental, non-profit research organization dedicated to advancing the scientific study, exploration and public understanding of Mars. He is also the director of the NASA Haughton-Mars Project, an international multidisciplinary field research project focused on Mars analogue studies at the Haughton impact crater site on Devon Island in the High Arctic.
“We can and should, right now, be looking for human landing sites where most if not all of our top priority science goals can be achieved,” Lee told Space.com. The human touchdown zone would likely offer more ways to extract water locally — something a robotic scouting mission could determine — and where it would make sense to establish a base for long-term exploration, he said.
At the crossroads
Lee is passionate about such a site, which he calls Noctis Landing, an apparently flat transition region between Noctis Labyrinthus (Latin for ‘Labyrinth of the Night’) and Valles Marineris proper.
Not only does Noctis Landing offer a large number and wide range of regions of interest for short-term exploration, it is also strategically located at the junction of Tharsis and Valles Marineris, which is key for long-term exploration. The area is notable for its maze-like system of deep, steep walls.
“If you head east or south from Noctis Landing, you go deeper into the Valles Marineris and can look for signs of past life,” Lee said. “If you go west or north from Noctis, you’ll climb the giant volcanoes of Mars with their many caves, and can look for extant life.”
No rock climbing required
The result is that the Noctis Landing site is unique, and is at the literal crossroads of the search for signs of past and present life on Mars.
When it comes to exploring Valles Marineris, the main advantage of Noctis Landing is that you can access all the rock layers in the canyon without having to resort to rock climbing, Lee said.
“Thanks to the giant Oudemans impact crater near Noctis Landing, giant slabs of Valles Marineris canyon walls have been laid flat there, ready to explore, one rock layer at a time, by simply driving along the canyon floor,” Lee added.
Late last year, Igor Mitrofanov of the Space Research Institute of the Russian Academy of Sciences in Moscow, Russia reported that a significant amount of hidden water has been discovered at the central part of Mars’ dramatic canyon system, Valles Marineris.
The observation came via the European Space Agency-Roscosmos ExoMars Trace Gas Orbiter (TGO). Mitrofanov is the principal investigator of the TGO-toted Fine Resolution Epithermal Neutron Detector (FREND) neutron telescope. This instrument maps the hydrogen – a measure of water content – in the top meter of Mars’ soil.
Mitrofanov and colleagues found evidence of unusually high amounts of hydrogen in the heart of Valles Marineris on Mars.
Unclear mix of conditions
“With TGO, we can look down to one meter below this dusty layer and see what is really going on beneath the surface of Mars – and, crucially, locate water-rich ‘oases’ that could not be detected with previous instruments,” said Mitrofanov (opens in a new tab) in an ESA-issued statement.
“Assuming that the hydrogen we see is bound to water molecules, as much as 40% of the near-surface material in this region appears to be water,” Mitrofanov said.
As the ESA statement puts it, the detection suggests that “a special, as yet unclear, mix of conditions must be present in the Valles Marineris to preserve the water – or that it is somehow replenished.”
Mitrofanov and his research associates published their work (opens in a new tab) in the March 2022 issue of the journal Icarus, stating, “Such ice is not only an exciting material for searching for frozen proto-life fragments or complex organic molecules from the early era of Mars, but is also an indispensable natural resource for future Martian- exploration that is easy to exploit.”
NASA’s Lee emphasized the exciting finding that there is frequent occurrence of fog in Valles Marineris. “Although the average Martian atmosphere is generally considered to contain too little water vapor to be worth compressing and exploiting, the presence of ice fog, the most likely explanation for the fog banks often filling the Valles Marineris, indicates that the Martian atmosphere may be locally supersaturated in water, possibly up to quantities worth extracting,” he said.
The presence of nebula in Valles Marineris, Lee said, also suggests that at least some of the hydrogen detected by Mitrofanov and his colleagues is likely to be in the form of H2O, not just water of hydration in minerals.
Taking to the air
Scouring Valles Marineris for its scientific holdings could be augmented by aerial vehicles, said Abigail Fraeman, a researcher and assistant project scientist at the Mars Science Laboratory at NASA’s Jet Propulsion Laboratory.
This view is clearly supported by the airborne success of NASA’s Ingenuity Mars helicopter at Jezero Crater.
“We can begin to imagine all kinds of possibilities for future Mars exploration with aerial resources,” Fraeman told Space.com. “One of the advantages of exploring Mars from the air is the ability to travel much longer distances over terrain that would be too treacherous for rovers.”
Fraeman said Valles Marineris is one example of an area that could really benefit from helicopter exploration. “This platform may enable us to explore sections of truly ancient crust exposed in the walls of the canyon, the steeply layered sedimentary deposits in the center of the canyon, and even the mysterious recurrent slopes that occur on steep slopes throughout the Valles Marineris and can form with very salty liquid water.”
Exploring these features, Framman added, “would help us answer questions about the entire history of Mars, from its initial formation to the present day, and provide unprecedented insight into mechanisms that influence the climate and habitability of Mars, as well as rocky worlds outside our solar system.”
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