The chief scientist of NASA’s Perseverance Mars probe is excited about the material that was deposited in the rover’s sample tubes, both as it fell on the surface of Mars and inside the rover itself as it moved through Jezero Crater.
Given the Mars samples that Perseverance has collected so far, could one of those samples be what the rover was sent to look for: evidence of past microbial life on the Red Planet?
The preliminary finding raises the need to return these Martian samples to Earth so that these valuable collectibles from the Red Planet can be sent to laboratories for more rigorous analysis.
Related: If there is life on Mars, don’t count on return missions to find it, scientists say
Live question
Caltech’s Kenneth Farley, project scientist for NASA’s Perseverance Mars rover program, briefed the Extraterrestrial Materials Analysis Group (ExMAG) during a meeting held 13-15 May in Houston, Texas.
Labeled “Lefroy Bay,” Farley pointed to this sample collected by the Perseverance rover, which was found to contain hydrated silica. Here on Earth, this mineral has the highest potential to preserve signs of ancient life.
So there is a living question that needs an answer: Maybe Lefroy Bay bears preserved signs of ancient life on Mars?
Paleoenvironmental conditions
“The Lefroy Bay sample and two other samples from the same unit — the ‘Margin Unit’ — are aboard Perseverance,” Farley told Space.com. “The Margin Unit samples are abundant in carbonate and silica, clearly indicating the dominant role of liquid water in their formation,” he said.
But whether it was surface water in a lake or river, or groundwater, remains uncertain, Farley added. Both could represent an ancient (older than 3.4 billion years old), habitable Martian environment, he said.
These samples host phases that are very useful on Earth for creating “paleoenvironmental” conditions, Farley noted, and may also preserve biological signatures. “As such, these samples are uniquely important to return to Earth for further study,” Farley said.
Objective: set in stone
Perseverance “is about to make a really fundamental transition in the exploration of the environment that we’re working in,” Farley explained in his briefing to ExMAG. “One of the challenges we face,” he said, “is that this is not a great terrain to drive the rover on.”
So far, the machine has traveled about 27 kilometers on Mars after being dropped into the area by a skyscraper on February 18, 2021. The robot’s goal is set in stone: “Look for signs of ancient life and collect rock and regolith samples for a possible return to Earth,” NASA explains.
But why was the 28-mile-wide (45-kilometer) Crater Lake chosen as the rover’s survey site?
Scientists believe that the area was once flooded and was home to an ancient river delta. Crater Lake is expected to literally “spill” the beans about the nature of Mars’ wet past to bounce back again and again. More than 3.5 billion years ago, river channels overflowed the crater wall to form the lake.
It is possible that microbial life could have lived in the Lake during one or more such wet periods. If true, evidence of the remains of these tiny creatures could be discovered in lakebeds or shoreline deposits.
Rover challenges
As for the overall condition of the Perseverance rover, Farley noted several problems: First, the loss of wind sensors that are part of the Mars Environmental Dynamics Analyzer (MEDA), built by an international team led by Spain’s Centro de AstrobiologÃa. “We’ve lost the wind sensors for the most part. They’re basically out of order,” he announced.
The spectroscopic parts of the Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals robotic arm, SHERLOC for short, are also questioned. This is because the lens hood is no longer working properly. However, there is some preliminary work that suggests scientists may be able to restore SHERLOC’s spectroscopic capabilities. “We’ll know more about that in the coming months,” Farley said.
Three Forks Warehouse
The rover was sent to Mars with 38 tubes that could be used to collect rock, regolith and even atmospheric samples. “We’re about two-thirds of the way through collecting samples,” Farley explained.
The robot on duty has taken samples of igneous rocks, mud, sandstone/pebble conglomerate, carbonate-silica-olivine, as well as upper Martian sand, and captured a whiff of the Martian atmosphere.
Earlier in her journey to Mars, Perseverance dropped 10 sealed sample tubes at a depot site called “Three Forks” in Jezero Crater. The plan is for the Mars Sample Return (MSR) mission to pick up sample tubes in the future to rocket these bits and pieces of Mars back to Earth.
However, this joint venture between NASA and the European Space Agency is now undergoing a detailed review due to the projected cost of $11 billion and the expected, but not satisfactory, time frame for such a complex endeavor.
Stay the course
Farley told the ExMAG group that rover operators are working to qualify Perseverance for a 55-mile (90-kilometer) traverse, which will allow it to make its way to resurface the landscape.
“Obviously there’s a huge amount of uncertainty about what the MSR will be. We’re waiting to see how we play a role in that on the Perseverance mission,” Farley said. “But for now, we’re going to stay the course. We’re going to continue doing pretty much as we have been, with a strong focus on sampling.”
Now on the rover’s travel itinerary, it completes tasks in an area called Bright Angel, then moves up to the rim of the crater, where the rover can examine fundamentally different geology, Farley added.
As the rim climbs, “we’re going to get the sampling done quickly. The sooner we do the sampling, the sooner we can all rest easy … that we’ve done our job,” Farley said.
What happens next for Perseverance is in a state of TBD.
“Maybe we’ll go back to the bottom of the crater to rendezvous with the MSR, maybe not. It will depend on what actually happens with the MSR,” Farley concluded.
Editor’s note: The original version of this story included this sentence: “While sifting through Mars samples collected by Perseverance, scientists say one tube appears to be full of what the rover was looking for: evidence of past microbial life on the Red Planet.” However, this is too strong a claim; the story was amended at 7:15 PM ET on May 20 to replace the above text with the following: “Given the Mars samples that Perseverance has collected so far, one of these samples could be what the rover was sent to find in the first place: evidence of past microbial life on the Red Planet?”