Curiosity's Shattered Mars Rock Could be Science Goldmine
'Mojave' may have cracked under the pressure from Curiosity's drill, but mission scientists are excited about studying fresh rock that hasn't been exposed since its formation millions of years ago.
Yesterday, on Sol 867 of its mission, Curiosity began drilling operations on a slab of bedrock at the base of Mount Sharp - but in so doing, the delicate target rock broke apart.
Although the slab might not be suitable for further drilling, mission scientists are excited by the opportunity to study the shattered rock left in Curiosity's wake.
"The rock target Mojave that we drilled into yesterday is part of a larger expanse of fractured, soft bedrock at the Pahrump Hills site," Mars Science Laboratory's project scientist Ashwin Vasavada, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., told Discovery News.
In September, Curiosity arrived at Pahrump Hills, a small foothill at the base of Mount Sharp in the center of Gale Crater, and the mission has been studying the area ever since, trying to understand how the 3.5 mile high mountain formed. To do this, the rover is making extensive use of its suite of robotic geologist's tools to drill into and chip away at the bountiful array of bedrock.
After cleaning the surface of the rock, which has been named "Mojave," it became clear that the rock contained crystallized mineral deposits that likely formed when Mars was a much wetter place. So to understand the nature of the deposits, mission managers gave the go-ahead to begin a test drill.
However, rather than smoothly boring into the rock, Mojave shattered, an outcome that didn't surprise Vasavada's team.
"We've seen similar fractured bedrock before and even cracked it on previous drill attempts in other locations," he said. "So while we can't necessarily predict it in advance, it also wasn't terribly surprising to crack the rock and dislodge a few fragments of it."
Vasavada did point out, however, that the rock will still need to be evaluated to see if it is still scientifically interesting enough for further drilling. Regardless, as the rock is fractured, a geological opportunity has presented itself.
"One nice outcome of yesterday's drill test was that a few rock chips were created and now are sitting on the surface of the bedrock," he said. "It's rare for Curiosity to get to study freshly broken rock surfaces, where the effects of weathering or dust might be minimized.
"It's the reason geologists on Earth carry rock hammers, to create fresh surfaces. So we're pretty excited to take some close-up images and compositional measurements of those fragments," added Vasavada.
Whether or not Mojave is suitable for further drilling seems academic; exposing the material from freshly-cut material that hasn't been exposed since the rock formed billions of years ago could provide a wonderful opportunity for Curiosity to zoom in and record fine-scale structures that we may never have otherwise seen.
The view of Curiosity's robotic arm from the rover's front hazcam while carrying out drilling operations on "Mojave" on Jan. 13, 2014.