NASA’s Mars Rover Perseverance finds surprises at Jezero Crater, including organic material – SpacePolicyOnline.com
A year and a half after landing on Mars, NASA’s Perseverance rover is hard at work studying an ancient river delta at Jezero Crater and discovers it’s not what scientists expected. The rock types reveal a complex geological past and some contain organic compounds in an environment that might have been suitable for microbial life. Most scientists don’t believe life currently exists on Mars, but there may be eternities. They’re on a “treasure hunt” for evidence, though a definitive answer will likely have to wait until the samples Perseverance is collecting are back on Earth.
Although arid today, water flowed on the surface of Mars in the distant past. Jezero Crater is home to a delta formed around 3.5 billion years ago where a river and a lake converged. NASA chose it for Perseverance, also known as Mars 2020, precisely because of its scientific potential.
During a briefing at the Jet Propulsion Laboratory today, Perseverance project scientist Ken Farley of the California Institute of Technology explained that they plan to find sedimentary rocks that form when particles settle in an environment aqueous. But they also found igneous rocks that form deep underground from magma or volcanoes on the surface.
“This juxtaposition provides us with a rich understanding of the geologic history after the crater was formed and a diverse suite of samples. For example, we found sandstone that carries grains and rock fragments created far from Jezero crater – and a mudstone that includes intriguing organic compounds,” Farley said.
Organic material has already been found on Mars with NASA’s Curiosity rover, which landed in 2012 and is still busy studying another part of the Red Planet.
What is different now is that this area could have been hospitable to life.
“In the distant past, the sand, mud and salts that now make up the Wildcat Ridge sample were deposited under conditions where life could have thrived,” Farley said. But it is too early to draw firm conclusions on this. “As good as our instruments on board Perseverance are, further conclusions regarding the contents of the Wildcat Ridge sample will have to wait until it is returned to Earth for further study.”
Perseverance’s SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) instrument discovered organic molecules. JPL’s Sunanda Sharma said SHERLOC “has found signals that we think may be coming from organic matter on every target we’ve observed” so far. Between the organic discoveries of Curiosity and those of Perservance, it appears that “organic material seems to persist in a very harsh Martian surface environment, which is very exciting for us”.
“To put it simply, it’s a scavenger hunt for potential signs of life on another planet, organic matter is a clue and we get stronger and stronger clues as we go through our delta campaign. Personally, I find these results so moving because I feel like we are in the right place with the right tools at a pivotal time. Mars 2020 gives us a better understanding than ever of the Martian surface to select samples And then Mars Sample Return is perhaps the best chance to answer a very deep question: are we alone in the universe?—Sunanda Sharma
Perseverance collects samples in cigar-shaped tubes that will be picked up by future spacecraft as part of the US-European Mars Sample Return campaign.
David Shuster, a scientist of samples returned by Perseverance at the University of California, Berkeley, said “it’s safe to say ‘the sample from Wildcat Ridge and another from Skinner Ridge’ are two of the most important that we will collect during this mission”. They record the “conditions of a thermally habitable environment”.
Some of the sample tubes will be left on the ground in a “depot” at Jezero Crater, while others will remain aboard the rover. Rick Welch, associate director of JPL’s Perseverance program, said they believe they have identified a suitable location for the deposit, smooth and flat for the sample return lander. They plan to leave 10 to 11 sample tubes there before the rover leaves to explore other parts of the crater and collect more samples. It has a total of 43 hits.
NASA and ESA recently redesigned the Mars Sample Return mission. Previously, a spacecraft combining a European-built Sample Fetch Rover and a NASA rocket to propel the samples into orbit around Mars reportedly landed on Mars. The rover would move across the surface to retrieve the samples, bring them back and transfer them to a capsule inside the rocket. Once in orbit, the capsule would be transferred to an ESA Earth Return Orbiter for the return trip to Earth.
The new blueprint omits the Sample Fetch Rover. Instead, the Sample Return Lander will land near the depot. NASA will provide two tiny helicopters like the Ingenuity Helicopter on Perseverance that can pick up the tubes one at a time and fly them to the lander. NASA anticipates that Perseverance will also be operating at this time and can meet the lander to deliver the samples it still has on board. NASA and ESA are still designing the mission and timeline, but the current plan is for the samples to be back on Earth in 2033.
As Sharma said, all of this research is devoted not only to understanding the history and evolution of Mars as a planet, but also to the question of whether it ever hosted life.
Farley stressed that any evidence of potential biosignatures does not mean life existed there.
“I want to be very careful in defining potential biosignatures. This is something we have discussed a lot within the science team and I want to make sure everyone understands the concept of potential biosignatures.
Potential biosignatures are something that may have been produced by life, but could also have been produced in the absence of life. One point about a potential biosignature is that it requires further investigation to come to a conclusion. This is how science works. We don’t always know the answer. We have assumptions. The rocks we studied in the delta have the highest concentration of organic matter we have ever found during the mission. You are going to know more about it. And of course, organic molecules are the building blocks of life.
So this is all very interesting in that we have rocks that have been deposited in a habitable medium in a lake that are transporting organic matter. We do not yet know the significance of these findings. These rocks are exactly the kind of rocks that we have come to study both with the rover and scientific instruments and also to bring back to Earth so that they can be studied in terrestrial laboratories. Then time will tell what’s in those rocks. —Ken Farley
JPL built and manages Perseverance. JPL is a federally funded research and development center operated for NASA by Caltech.
Perseverance launched on July 30, 2020 and landed on February 18, 2021.