In the spring semester of his junior year, Lee Saper ’12 began a journey that would let him explore the surface of Mars.
In 2011, Saper applied for the Rhode Island Space Grant Consortium, a NASA-funded scholarship for undergraduate research. The scholarship — in addition to a conversation Saper had with John Mustard, professor of geological sciences — culminated in a senior thesis and a study providing evidence there was once water in the subsurface of Mars. That study, currently in press in the journal Geophysical Research Letters, was published online Wednesday.
Saper, Mustard and Brown’s Department of Geological Sciences used high-resolution images from the Mars Reconnaissance Orbiter to map more than 4,000 raised ridges on Mars’ surface in two specific areas, Saper said. They hypothesized the ridges are actually fossilized remnants of cracks in the crater floor — originally formed by the force of impact that produced the crater itself or adjustment of the crust after the impact. Water in the subsurface flowed into these cracks and deposited minerals that formed a layer harder than the surrounding crust. Over time, the crust eroded away, leaving raised ridges, Mustard said.
“The minerals around the ridges today are consistent with water once being present there,” Saper said. “So we thought perhaps the water was important in their formation in the first place.”
If water was present in the ancient cracks, life forms possibly were as well.
“The surface (of Mars) has always been inhospitable, cold, filled with toxic radiation,” Mustard said. “The subsurface is potentially a more stable place” for microbes to form.
“These ridges are the remnants of the Martian subsurface condominium complex” where microbes theoretically lived, he said.
But the study had limitations, particularly the areas on Mars that Saper mapped — Nili Fossae and Nilosyrtis.
“(Saper) mapped a large area, but in the context of Mars, it is very small,” Mustard said.
A follow-up study could examine the mineral composition of other ridges on the Red Planet’s surface. “There might have been a subsurface geological system on ancient Mars,” Saper said.
After graduating with an Sc.B in geology and chemistry, Saper is an assistant staff scientist for Malin Space Science Systems in San Diego, a company that designs, builds and operates satellites and cameras. Saper controls one of the cameras on a satellite orbiting Mars.
Saper and Mustard said they hope to continue their study in the future using images from many more areas on Mars.
“We can see where (the ridges) exist, where they don’t exist and put them in the context of the study,” Saper said.
“It’s a matter of finding the right time and additional people,” Mustard said. “We would like to extend the study as much as we can.”
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