A rock sample from Mars gathered last summer shows chemical indicators that may point to previous microbial life, although non-biological explanations are still feasible, as stated by NASA.

In July 2024, the Perseverance rover found the rock. The extracted sample, referred to as Sapphire Canyon, is now the strongest evidence suggesting that life may have existed on ancient Mars, according to the U.S. space agency.

NASA conducted a press conference on Wednesday to reveal that the rover’s discoveries have undergone peer review in the journal Nature, a vital step in substantiating the findings. Associate administrator Nicky Fox emphasized that the sample does not contain life but rather a fossilized remnant that suggests the possibility of past life.

“It’s similar to finding remnants from a meal, potentially left behind by a microbe,” she stated.

The confirmation of this potential indicator of life remains uncertain. The sample is still on Mars, and it is unknown if a NASA mission will bring it back to Earth for additional analysis, which is necessary for definitive conclusions. In January, before President Donald Trump assumed office, NASA officials discussed two possible new strategies for Mars Sample Return to lower costs. The final decision would ultimately depend on the Trump administration, whose budget proposal includes plans to cancel this mission.

Acting NASA Administrator Sean Duffy, appointed by Trump two months ago, appeared frustrated by reporters’ inquiries concentrating on the mission and its funding instead of the research announced previously.

“We have some of NASA’s brightest individuals with us,” Duffy remarked. “I anticipated your questions would center more around this thrilling news.”

The sample collected from Cheyava Falls is one of 27 rock cores the rover has acquired since its landing on Mars in February 2021. It was located in Neretva Vallis, where a prior river once flowed into Jezero Crater, the region Perseverance is investigating.

The rock is a reddish, clay-rich mudstone with flecks and leopard-like spots indicating chemical reactions akin to those utilized by certain Earth microbes for energy. It contains organic carbon, sulfur, phosphorus, and iron-rich minerals that might have supported life billions of years in the past. While these minerals can form without biological processes, the local conditions render a non-biological explanation less likely.

“When we observe such features on Earth, minerals are frequently byproducts of microbial metabolism digesting organic material,” remarked Joel Hurowitz, lead author of the Nature paper. “Nonetheless, non-biological methods of forming these features cannot be dismissed.”

For example, an alternative process to generate an iron-sulfide mineral known as greigite, present in the sample, could involve heating the rock, according to Hurowitz, a planetary scientist at Stony Brook University.

Perseverance scientists have maximized what they can learn from the sample using the rover’s instruments. On Earth, researchers could perform more comprehensive analyses. Advanced tools could search for complex organic compounds, DNA, cellular structures, and more.

Without the sample on Earth, scientists will continue examining rover data by experimenting with surrogate materials in laboratories to determine if similar outcomes can be produced through non-biological means.

Mars Sample Return has been stalled since a review indicated it would exceed $11 billion and require nearly two decades. NASA sought input from the aerospace sector to manage costs and development. Several companies proposed various concepts, including modifying Artemis moon landers and reexamining the mission’s final phase.

The mission remains a potential option, stated the acting administrator, who also serves as the U.S. transportation secretary, and the agency will persist in exploring cost-effective measures to make it viable.

“If we lack the resources for the proper missions or personnel, I will seek additional funding from the president and Congress,” he commented. “I am confident that with the president’s budget, we can fulfill our mission.”