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PSI’s R. Aileen Yingst Named to Head MAHLI Instrument on Mars Curiosity Rover

April 20, 2022


This image shows the Mars Hand Lens Imager (MAHLI) on NASA's Curiosity rover, with the Martian landscape in the background.

Credit: NASA/JPL-Caltech/MSSS.


Planetary Science Institute’s R. Aileen Yingst has taken the helm of  the Mars rover Curiosity’s version of the magnifying hand lens that geologists usually carry with them into the field. 

Yingst, a Senior Scientist at PSI, was named Principal Investigator of the Mars Hand Lens Imager (MAHLI), that provides earthbound scientists with close-up views of the minerals, textures, and structures in Martian rocks and the surface layer of rocky debris and dust. MAHLI's main objective is to help the NASA Mars Science Laboratory science team understand the geologic history of the landing site on Mars. MAHLI also helps researchers select samples for further investigation. 

“MAHLI is designed to image the very small – the individual grains that make up a rock or a regolith. Every grain has a story, and it is MAHLI's job to resolve the various grain characteristics – size, shape, color, texture – to be able to tell that story,” said Yingst, who has worked on the MAHLI project since 2005. 

Yingst, who moved up from Deputy Principal Investigator for MAHLI, said, “Moving up to PI means the buck stops with me. I'm responsible for the MAHLI investigation. I'm responsible for ensuring that we meet our science investigation goals, that the instrument is safe and healthy – or as safe and healthy as it can be on Mars – and that we adequately support the entire mission, including providing observations requested by other instruments or hardware.” 

The roughly 4-centimeter-wide (1.5-inch-wide) camera takes color images of features as small as 12.5 micrometers. MAHLI carries both white light sources, similar to the light from a flashlight, and ultraviolet light sources, similar to the light from a tanning lamp, making the imager functional both day and night. The ultraviolet light can be used to induce fluorescence to help detect carbonate and evaporite minerals, both of which indicate that water helped shape the landscape on Mars. 

“MAHLI's best resolution was purposely chosen to reveal the presence of rock grains smaller than sand-sized – meaning less than 60 microns across, or less than the width of a human hair. Such grains would likely have settled in a quiescent environment, like in a lake,” Yingst said. “What that means is that if MAHLI can resolve grains, they are sand-sized or larger, and could have been deposited by a number of processes, but if the grains are too small for MAHLI to resolve, they are likely silt-sized and it's far more likely that they settled in a lake environment, creating a mudstone. 

“Very early in the mission, MAHLI acquired images of a target named Sheepbed and those images confirmed that the target was a mudstone, thereby confirming that a lake once existed at Gale crater. One of our major mission goals was to find a habitable environment – obviously a lake qualifies – and MAHLI provided  confirming data of habitability at that former Gale crater lake,” Yingst said. 

“Looking ahead, my goal is to stay the course; the retiring PI did a fantastic job at keeping MAHLI safe, healthy, and working well. I'd like to retain all those good things. Also, we're in a place now in the mission where every day on Mars is a gift – we expected to have run out of power by now! So MAHLI has some room to perhaps take a few more risks in getting excellent science data to support mission goals. So for very compelling science, I'd like to see us stretch a little and give the science team more room to acquire important images.” 

Yingst’s work on MAHLI is funded through PSI by a subcontract from Malin Space Science Systems via a contract from NASA’s Jet Propulsion Laboratory.

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Aileen Yingst



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Aileen Yingst

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