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The University of New Brunswick’s contributions to space exploration continue to stretch across the solar system.

In the latest example, two university researchers helped uncover the first confirmed evidence of native, or elemental, sulfur on Mars.

Published recently in Science, the findings suggest sulfur-rich fluids were active beneath the planet's surface billions of years ago. Researchers propose the sulfur originated in subsurface ice and later formed elemental sulfur deposits. These deposits were trapped and protected by debris flows and avalanche material before being exposed by erosion, offering new insights into Mars' geological history.

The study involved 23 authors and researchers from organizations including NASA, the Canadian Space Agency, the University of Guelph, and Washington University in St. Louis.

UNB researchers Dr. Lucy Thompson and Dr. Catherine O'Connell-Cooper are among the paper's co-authors. They're responsible for operating the Alpha Particle X-Ray Spectrometer (APXS) - one of NASA’s Mars Curiosty Rover’s key instruments.

Thompson and O'Connell-Cooper, who work with UNB's Planetary and Space Science Centre (PASSC), help determine which geological targets the rover should investigate, collaborate with researchers across the mission, and analyze data APXS returns from Mars.

Thompson was one of the scientific leads for the Gediz Vallis campaign, a major investigation of a canyon system within Gale Crater that scientists had identified as a priority long before Curiosity landed on Mars in 2012.

At the centre of Gale Crater sits Mount Sharp, a five-kilometre-high mountain made up of layers of rock that scientists believe record a transition from wetter conditions on ancient Mars to the drier environment seen today. Gediz Vallis cuts through those layers, offering researchers a unique opportunity to study a later chapter in the planet's geological history.

It was during that campaign that the rover encountered an unusual field of bright rocks that stood out from the surrounding landscape.

APXS, a Canadian-built, funded, managed, and operated instrument mounted on Curiosity, was used to analyze the rocks and determine their composition. The results revealed something never before confirmed on Mars: native sulfur.

"All the sulfur that we'd found had pretty much been present as sulfate. So it was really unusual and surprising and exciting to find elemental sulfur," said Thompson.

Until now, sulfur identified on Mars had largely been found in compounds such as sulfates and sulfides. The newly discovered deposit consists of sulfur in its elemental form rather than sulfur bound within other minerals.

Both researchers have been involved with the Curiosity mission for more than a decade, contributing to investigations that continue to reveal new details about the Red Planet's past.

The paper's lead author is Dr. Scott VanBommel of Washington University in St. Louis, a Canadian researcher and former University of Guelph graduate student who conducted detailed analyses of the APXS measurements that confirmed the sulfur's elemental nature.

The discovery adds to the growing body of scientific knowledge generated by Curiosity and highlights the important role Canadian technology and expertise continue to play in planetary exploration.

Media contact

Hilary Creamer
hilary.creamer@unb.ca