NASA’s Perseverance Mars rover has unearthed new rock samples at the bottom of a Martian river in a search for evidence of past life.
Perseverance is in the midst of its second Martian rock collection campaign and has now collected four more sedimentary rock samples from a once-flowing river delta in Jezero Crater, bringing its collection to a total of 12 samples since it began on July 7th.
NASA chose the river delta because it offered the highest chance of finding signs of ancient microbial life. In ancient times – if NASA ever finds evidence – microbial life would have existed around 3.5 billion years ago when the river bed formed.
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Perseverance is plucking sedimentary rock from a part where the Martian River and a lake meet in Jezero Crater. The crater itself is 45 kilometers wide.
Thomas Zurbuchen, NASA’s deputy administrator for science in Washington, said Perseverance has collected an “amazing variety” of samples that will be shot back to Earth over the next decade in the Mars Sample Return campaign.
“We chose Jezero Crater for Perseverance to explore because we thought it had the best chance of providing scientifically excellent samples – and now we know we sent the rover to the right place,” Zurbuchen said in a press release.
For the retrieval campaign, NASA plans to launch the Sample Retrieval Lander to Mars in 2028 and land in Jezero Crater. The lander will carry a NASA-run Mars rocket and two small Mars helicopters. Only when the samples are returned to Earth will NASA scientists know exactly what they are made of.
But if SpaceX boss Elon Musk is right, humans could be on Mars before the rock samples return to Earth. Musk’s final bet is that the earliest date for humans on Mars is 2029.
Perseverance and its sibling Ingenuity landed on Mars on February 18, 2021, about seven months after launch from Cape Canaveral, Florida.
Perseverance’s first campaign explored the bottom of Jezero and collected igneous rock containing crystals that can tell exactly when they were formed. Instead of collecting sedimentary rocks now, igneous rocks form in molten lava or during volcanic activity.
The rover is equipped with a SuperCam with a rock evaporation laser, which scanned the rocks during the first campaign to determine that it was igneous rock covering the crater floor.
The two different rock types give NASA the ability to understand the geological history of the crater.
“The delta, with its diverse sedimentary rocks, contrasts nicely with the igneous rocks — formed from the crystallization of magma — discovered on the crater floor,” said Ken Farley, Perseverance project scientist of Caltech in Pasadena, California.
“This juxtaposition gives us a comprehensive understanding of the post-cratering geological history and a diverse sampling suite. For example, we found a sandstone containing grains and rock fragments that originated far from Jezero Crater — and a mudstone containing intriguing organic compounds.”
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The newfound evidence of organic molecules on Mars is more promising than the 2013 discovery by the Curiosity rover, which found evidence of organic material, NASA says.
What makes Perseverance’s discoveries intriguing is that the organic molecules found are in an “area where, in the distant past, sediments and salts were deposited in a lake under conditions where life could possibly have existed.” These were found in a section of the crater called Wildcat Ridge.
“In the distant past, the sand, mud, and salts that make up the Wildcat Ridge specimen were deposited in conditions where life could potentially have thrived—ancient life here on Earth—is important.” However, as powerful as our instruments aboard Perseverance are, further conclusions about what is contained within the Wildcat Ridge sample will have to await its return to Earth for in-depth study as part of the agency’s Mars Sample Return campaign.” said Farley.