Space and Science

Perseverance’s Martian rock samples may contain ancient water bubbles

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Two Martian rock samples collected by the Perseverance rover may contain evidence of ancient water bubbles, according to NASA.

The rock samples were found to include salt minerals, which may reveal insights about the ancient climate and habitability of Mars billions of years ago – and could even preserve evidence of ancient life, if it existed on the red planet.

Perseverance successfully collected its first two rock samples on September 6 and 8, nicknamed Montdenier and Montagnac, from the same rock called Rochette. The rover is currently exploring Jezero Crater, the site of an ancient lake more than 3 billion years ago.

“Because these rocks were of such high scientific potential, we decided to acquire two samples here,” said Katie Stack Morgan, Perseverance deputy project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

White flecks are visible in this image showing where Perseverance used its abrasion tool to grind away at the rock before drilling. These white flecks are salts.

The rocks within the crater could tell scientists about ancient volcanic activity in the area, as well as if water was present for long periods of time, or if it came and went as the climate fluctuated.

These two rock samples show that groundwater was likely present for a long time in the area.

“It looks like our first rocks reveal a potentially habitable sustained environment,” said Ken Farley, project scientist for the Perseverance mission at the California Institute of Technology, in a statement. “It’s a big deal that the water was there a long time.”

The Rochette rock is basaltic in nature, meaning it was likely made by ancient lava flows. Crystalline minerals within rocks like this can help scientists obtain extremely accurate dating and tell when the rock was formed.

The salt minerals within the rocks are the result of the rocks being altered over time. They could have formed when groundwater either changed the original minerals within the lava rock or when water evaporated and left the salts behind.

While the groundwater may have been part of the lake that once filled Jezero Crater and its river delta, scientists can’t discount the fact that the water may have traveled through the rocks even after the lake dried up and disappeared.

But the rocks give Perseverance’s science team hope; water was likely present long enough to create a habitable environment where ancient microbial life could have thrived.

The rover's PIXL instrument, or Planetary Instrument for X-ray Lithochemistry, revealed salt minerals (in yellow). Salt crystals could have trapped bubbles of ancient water.

These two samples are the first of more than 30 that will be collected by the rover and eventually returned to Earth by multiple missions, called Mars Sample Return, by 2031.

“What we’re planning to do is to launch a couple of missions,” said Meenakshi Wadhwa, Mars Sample Return principal scientist at JPL and Arizona State University. “One will be a sample retrieval lander which will actually pick up the samples and bring them into Mars orbit. Then there’s an orbiter, the Earth Return Orbiter, which will be capturing these orbiting samples, and then the return orbiter goes back to Earth.”

Once returned to Earth, a portion of the samples will be investigated in a multitude of ways, while the rest will remain sealed so that future scientists with better technology can study them – much like the Apollo lunar samples.

“These samples have high value for future laboratory analysis back on Earth,” said Mitch Schulte, mission program scientist at NASA headquarters, in a statement. “One day, we may be able to work out the sequence and timing of the environmental conditions that this rock’s minerals represent. This will help answer the big-picture science question of the history and stability of liquid water on Mars.”

The more samples Perseverance collects from intriguing points across the crater and river delta, the more likely scientists will be able to piece together the Martian puzzle that answers the ultimate question: Did life ever exist on Mars?

“One of the reasons we explore Mars is because it holds a rock record that’s been untouched for about three and a half to four billion years,” said Lori Glaze, director of NASA’s Planetary Science Division.

The two samples are currently stored within titanium tubes on the rover and will eventually be dropped at a site where a future mission can retrieve them.

The rover is gearing up for another drive to its next possible sample site called South Séítah, which is 656 feet (200 meters) away. This region, which was aerially scouted by the Ingenuity helicopter during its last two flights, is filled with sand dune-covered ridges, boulders and rock shards. Farley refers to some of them as “broken dinner plates.”

While the first two samples from the Rochette rock probably represent some of the youngest rock on the crater floor, South Séítah will likely be a treasure trove of older rock layers that reveal more about the history of the crater and its lake.

But we’ll have to wait. The beginning of October will create a communications blackout between Mars and Earth during the Mars solar conjunction, when the two planets are on opposite sides of the sun. Perseverance will probably begin its sampling exploration of South Séítah after this period, which will last for nearly two weeks, comes to an end.