Was there life on Mars? Perseverance scrapes up promising samples

Fact organic matter was found in sedimentary rock, which preserves fossils here on Earth, 'important'

NASA says its Perseverance rover has pulled up some exciting samples "deposited under conditions where life could potentially have thrived" after trundling around an ancient area of wetland that formed when a Martian river emptied water and sediment into a lake.

The space agency, which plans to bring the samples back to Earth in 2033, said its second science campaign is moving along swiftly: Perseverance has scooped up four samples already from the river delta in the Jezero Crater since July 7.

The fact the organic matter was found in such a sedimentary rock – known for preserving fossils of ancient life here on Earth – is important

Astrobiologists at the Jet Propulsion Lab (JPL) team, which looks after the rover and its operation, say this brings the total count of "scientifically compelling" rock samples to 12, but seem particularly interested in a rock the team has dubbed "Wildcat Ridge," where an intriguing sample was collected on July 20.

Wildcat Ridge is a rock about 3 feet (1 meter) wide that likely formed "billions of years ago as mud and fine sand settled in an evaporating saltwater lake," JPL said yesterday.

The agency revealed the rover abraded "some of the surface of Wildcat Ridge" to analyze it with its SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) instrument. The initial analysis, they said, shows the scrapings include "a class of organic molecules that are spatially correlated with those of sulfate minerals."

It wouldn't be the first time sulfate minerals have been found on Mars, but the team noted that when they are found "in layers of sedimentary rock [they] can yield significant information about the aqueous environments in which they formed."

Perseverance project scientist Ken Farley, based at Caltech university, said: "In the distant past, the sand, mud, and salts that now make up the Wildcat Ridge sample were deposited under conditions where life could potentially have thrived.

"The fact the organic matter was found in such a sedimentary rock – known for preserving fossils of ancient life here on Earth – is important."

Farley wouldn't be drawn to speculate further, though. "As capable as our instruments aboard Perseverance are, further conclusions regarding what is contained in the Wildcat Ridge sample will have to wait until it's returned to Earth for in-depth study as part of the agency's Mars Sample Return campaign."

The agency added that the geologic diversity of samples already carried in the rover was good, so much so that the team expects to drop off a few select tubes near the base of the delta in "about two months," after which the rover will keep exploring.

NASA and the European Space Agency intend to send spacecraft to Mars to collect the sealed samples and return them to Earth for analysis, launching an Earth Return Orbiter in 2027 and a Sample Retrieval Lander in 2028.

Perseverance will meet with the Sample Retrieval Lander to make the dropoff in a special capsule, but if it doesn't make that meeting, two helicopters stashed in the belly of the lander will fly out to find sealed samples deposited on the ground. The 'copters will then return to base where they'll be placed in a special capsule, and then that capsule will be placed into the 10ft (3 meter) tall Mars Ascent Vehicle (MAV), also initially stored in the belly of the lander, which will take it into the Red Planet's orbit.

Lockheed Martin won the contract to build MAV in February this year and various engineers are starting work on the myriad components and spacecraft that are going to bring the samples back from October this year. More on that intricate process here.

We know we don't have to tell you, but claiming any signs of ancient life on Mars carries a significant burden of proof. Nonetheless, getting a proper look at these uncontaminated samples could be a game-changer.

Laurie Leshin, JPL director, enthused: "That we are weeks from deploying Perseverance's fascinating samples and mere years from bringing them to Earth so scientists can study them in exquisite detail is truly phenomenal. We will learn so much."

Not long to wait then. ®