Thousands of strange white rocks found on Mars. Will they ever be brought to Earth?

By | April 4, 2024

Mars’ rusty red surface may have given it its famous “Red Planet” status, but it also appears that there are thousands of white rocks strangely littering the Martian ground. NASAs Perseverance rover, a robotic geologist who has been exploring the Jezero crater since early 2021, confounded scientists when it delivered images of more than 4,000 light-colored pebble-sized rocks scattered across the crater floor.

“These are very unusual rocks and we’re trying to figure out what’s going on,” said Candice Bedford, a planetary scientist at Purdue University in Indiana and a member of the Mars 2020 science team, said last month at the Lunar and Planetary Science Conference (LSPC).

The announcement comes as NASA completes an architectural overview of returning Martian rocks to Earth as part of the agency’s ambitious Mars Sample Return (MSR) program.

Related: NASA’s Perseverance rover captures 360-degree view of Mars’ Jezero crater (video)

The white rocks pictured are what scientists call ‘rafts’, meaning they have been removed and transported from their original habitat; some are smooth with pits, while others appear to be an amalgamation of multiple layers. Initial analyzes conducted using Perseverance’s instruments showed that the rocks are dehydrated – not only in terms of water content, but also in other minerals, including iron, magnesium, calcium and sodium. “These are pretty depleted in a lot of things,” Bedford said.

The team is particularly interested in the origins of these unusual rocks, because their sources could reveal clues about the Red Planet’s past, including exactly when water might have flooded the Jezero crater, which today we regard as an arid piece of land . Despite discovering more than 4,000 such rocks, Perseverance has failed to see even a hint of what is known as an “outcrop” associated with the rocks, which is essentially a bedrock with similar properties that protruding from the surface of Mars.

The dehydrated nature of the rocks suggests that they were heated and altered by lava flows asteroid Impacts elsewhere on Mars and later dumped on the crater floor, Bedford said. Whatever the specific process may have been, she and her team suspect that it occurred relatively recently in terms of the geological history of the Jezero crater.

The Perseverance rover, which has traveled more than 15 miles since arriving on Mars, celebrated 1,000 days of science last December, which also marked the official completion of the mission for which it was originally designed. 26 of the 43 Mars rock sample tubes have now been filled, members of the mission team shared at LPSC. “Each sample contains countless grains that we could study essentially forever,” says Benjamin Weiss, a professor of planetary science at the Massachusetts Institute of Technology and a member of the Mars 2020 team.

As part of a bonus mission which launched this spring, Bedford said Perseverance began making its way to the rim of Jezero Crater, and its long-range camera has already captured more light-colored rocks in that area.

However, all these enigmatic rocks aren’t the only reason scientists are eager to take Perseverance to the crater rim and possibly beyond. There they believe that a unique geology exists, one that has not previously been found in the crater floor. That includes pre-Jezero rocks, which may contain data on the formation of Mars’ crust and early climate. It may even contain evidence of biosignatures.

Scientists are currently tagging a number of interesting sampling locations while mapping the rim itself in more detail, says Lisa Mayhew, a research associate at the University of Colorado, Boulder. Of great interest to scientists is a site adjacent to the Jezero crater called Nili Planum, whose rocks they believe formed in warm conditions at a time when life most likely evolved – if it ever existed at the present barren world, at least. Sampling such rocks “would provide tremendous added scientific value to the cache that already exists on Perseverance,” Mayhew said.

However, that scientific value cannot be fully realized until these rocks are returned Soil.

Scientists must time-date them using equipment on Earth, without which they would have no precise timeline for when the Red Planet was habitable and when it dried out. “It’s not an exaggeration to say it will revolutionize our understanding of Mars,” Weiss said.

Questions remain about the MSR program, which NASA runs, including when and how the agency plans to return the collected samples to Earth. Last October, NASA commissioned a response team (MIRT) to evaluate alternative approaches to MSR after an independent review board (IRB) determined that the current architecture would lead to cost and schedule overruns.

Related stories:

— Perseverance rover celebrates 1,000 Martian days on the Red Planet

— Strange subterranean polygons on Mars hint at the Red Planet’s wet past

— How the Perseverance rover captured its youngest samples from Mars’ Dream Lake (video)

“A lot of the work has already been completed,” said Meenakshi Wadhwa, a planetary scientist at Arizona State University and MSR’s chief scientist. MIRT’s recommendation report for a new approach was expected in late March, followed by a revised plan and budget by NASA sometime in April, she said.

The agency’s budget proposal for the 2025 financial year, made public on March 11, has allocated $2.7 billion for planetary science, but funding for MSR remained “TBD.” NASA’s budget for this year and next year will be announced in April after the MIRT review is completed, NASA Administrator Bill Nelson told reporters at the time.

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