There are many in the Mars exploration community who see Valles Marineris as a “general” site ripe for human exploration that may uncover the planet’s history and its ability to support microbial life.
But what is the best way to study the multifaceted geology of this place? Can future crews on the Red Planet safely enter this vast canyon system? And what awaits those exploring a vast region branded as the Grand Canyon of Mars?
Valles Marineris is a huge feature; a canyon system that bisects the Martian surface and stretches 2,500 miles (4,000 kilometers) and covers about one-fifth of the circumference of Mars. In some places, this colossal chasm is 200 km wide. At certain points, the canyon floor reaches a depth of 8 km.
Bottom line: That’s a lot deeper than Earth’s Grand Canyon.
Related: Glaciers on Mars likely helped carve the Red Planet’s “Grand Canyon.”
To encourage on-site human studies in the Valles Marineris, some scientists have pinpointed and tentatively named an area known as “Noctic Landing”. Its strategic location allows for the shortest possible surface excursions to the Martian volcanic plateau of Tharsis, as well as to Valles Marineris – that magnificent feature and region on the Red Planet that reveals the longest record of Martian geology and evolution over time.
Tharsis is the area of 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 flows are within the driving range of future pressurized rover traverses.
science at the top
“I think when it comes to planning manned missions to Mars, we may have gotten past the point where we’re just thinking about fictional scientific goals in a location-agnostic way,” 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, not-for-profit research organization dedicated to advancing scientific inquiry, exploration, and public understanding of Mars. He is also Director of NASA’s Haughton-Mars Project, an international multidisciplinary fieldwork project focused on analogous studies of Mars at the site of the Haughton impact crater on Devon Island in the high Arctic.
We can and should now be looking for human landing sites where most, if not all, of our top science goals could be achieved, Lee told Space.com. That human touchdown zone would likely provide multiple opportunities to sample water at the site — something a robotic scouting mission might detect — and where it would make sense to establish a base for long-term exploration, he said.
At the crossroads
Lee believes that one such site, which he calls Noctis Landing, is a seemingly flat transition region between Noctis Labyrinthus (Latin for “the labyrinth of the night”) and the actual Valles Marineris.
Not only does Noctis Landing offer a large number and wide range of regions of interest for near-term exploration, it is also strategically located at the intersection of Tharsis and Valles Marineris, which are critical for long-term exploration. The area is characterized by a labyrinthine system of deep, steep-walled valleys.
“Heading east or south from Noctis Landing takes you deeper into the Valles Marineris and you can look for signs of past life,” Lee said. “If you drive west or north from Noctis, you can climb the huge volcanoes of Mars with their many caves and search for existing life.”
No climbing required
The result is that the Noctis Landing site is unique in that it literally sits at the crossroads of the search for signs of past and present life on Mars.
As for exploring Valles Marineris, the main benefit of Noctis Landing is that you can access all of the canyon’s rock strata without resorting to rock climbing, Lee said.
“Thanks to the huge Oudemans impact crater near Noctis Landing, huge slabs of the Valles Marineris canyon walls were laid flat there, which you can explore rock layer by layer just by traversing 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 had been discovered in the central part of Mars’ dramatic canyon system, Valles Marineris.
The observation was made by the European Space Agency’s Roscosmos ExoMars Trace Gas Orbiter (TGO). Mitrofanov is the principal investigator of the TGO-borne Fine Resolution Epithermal Neutron Detector (FREND) neutron telescope. This instrument maps the hydrogen – a measure of water content – in the top meter of the Martian soil.
Mitrofanov and colleagues found evidence of unusually high levels of hydrogen in the heart of Valles Marineris on Mars.
Unclear mix of conditions
“With TGO we can look up to a meter below this dusty layer and see what’s really going on beneath the surface of Mars – and most importantly, locate water-rich ‘oases’ that could not be detected with previous instruments,” explained Mitrofanov (opens in new tab) in a statement issued by ESA.
“Assuming that the hydrogen we see is bound into water molecules, up to 40% of the near-surface material in this region appears to be water,” Mitrofanov said.
As the ESA statement states, the discovery suggests that “a particular, as yet unclear, mix of conditions must exist in Valles Marineris for the water to be sustained – or somehow replenished.”
Mitrofanov and his research associates published their work (opens in new tab) in the March 2022 issue of Icarus magazine, which states: “Such ice is not only fascinating material for the search for frozen proto-life fragments or complex organic molecules from the early Martian epoch, but also an indispensable natural resource for the future one.” Exploration of Mars that’s easy to exploit.”
NASA’s Lee underscored the intriguing finding that fog is common in Valles Marineris. “While it is generally believed that the average Martian atmosphere contains too little water vapor to be worth compressing and exploiting, the presence of ice fog, the most likely explanation for the fog banks that frequently fill Valles Marineris, suggests that this could be the Martian atmosphere locally supersaturated with water, possibly to levels worth extracting,” he said.
The presence of fog in Valles Marineris, Lee said, also suggests that at least some of the hydrogen discovered by Mitrofanov and his collaborators is likely in the form of H2O, and not just in minerals as the water of hydration.
Sweeping Valles Marineris of its science holdings could be augmented by airborne vehicles, said Abigail Fraeman, a research scientist and associate project scientist at the Mars Science Laboratory at NASA’s Jet Propulsion Laboratory.
This view is clearly supported by the flight success of NASA’s Ingenuity Mars helicopter at Jezero Crater.
“We can think of all sorts of possibilities for future aerial exploration of Mars,” Fraeman told Space.com. “One of the benefits 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 an example of a site that could really benefit from helicopter exploration. “This platform could allow us to explore sections of truly ancient crust exposed in the walls of the gorge, the steeply stratified sedimentary deposits in the center of the gorge, and even the mysterious recurring slope lines that occur and are formed on steep slopes throughout Valles Marineris.” could be caused by very salty liquid water.”
Exploring these features, Fraeman added, “would help us answer questions about the entire history of Mars, from its earliest formation to the present, and provide unprecedented insight into mechanisms affecting Martian climate and habitability, as well as rocky worlds.” beyond our solar system.”
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