In the first inventory of minerals on another planet, NASA’s Mars rover Curiosity has found soil that bears a striking resemblance to weathered, volcanic sand in Hawaii, scientists said last week.
The rover uses an X-ray imager to reveal the atomic structures of crystals in the Martian soil, the first time the technology, known as X-ray diffraction, has been used to analyze soil beyond Earth.
Curiosity found that the Martian sand grains have crystals similar to basaltic soils found in volcanic regions on Earth, such as Hawaii. Scientists plan to use the information about Mars’s minerals to figure out if the planet most like Earth could have supported and preserved microbial life.
“The mineralogy of Mars’s soil has been a source of conjecture until now,” said Curiosity scientist David Vaniman of the Planetary Science Institute in Tucson.
“This interest isn’t just academic,” he added. “Soils on planets’ surfaces are a reflection of surface exposure processes and history, with information on present and past climates.”
Specifically, scientists want to understand what conditions existed to allow the particular minerals to form.
The first Martian soil scoop is mineralogically similar to basaltic materials and composed primarily of feldspar, pyroxene and olivine. About half the soil is non-crystalline materials, such as volcanic glass, that form from the breakdown of rocks.
Several processes can account for this weathering, including interaction with water or oxygen, similar to how rust forms on iron-metal surfaces.
Brute force, such as sandstorms or meteorite impacts, also could account for the soil’s weathered components, said chemist Douglas Ming of NASA’s Johnson Space Center in Houston.
The Curiosity rover landed inside a giant impact crater near the Martian equator in August for a two-year, $2.5 billion mission, NASA’s first astrobiology expedition since the 1970s-era Viking probes.
While X-ray diffraction has been around for a century, using the technology on Mars required years of work to scale down refrigerator-size equipment into something as small as a shoe box.