Organic carbon, even if it didn't come from life, should be all over Mars, which, like Earth, is believed to have been pummeled by organic-rich comets and asteroids early in its history.
The destructive effects of ultraviolet and cosmic radiation, combined with what appears to be a ubiquitous layer of organic-consuming chemicals produced by so-called perchlorates on the surface of Mars, have driven the quest for organics underground. Inside rocks may be evidence of a different, organic-friendlier time in the planet's history.
On Tuesday, scientists with NASA's Mars Curiosity rover mission are due to report the first chemical analysis of powder drilled out from inside a rock at the Gale Crater landing site.
Scientists already know that the inside of the target rock is not as oxidized as its exterior.
The powder was delivered into a sampling scoop and photographed before being processed by two onboard laboratory instruments. The powder appeared gray, while the rock's surface, like most of Mars, is red due to oxidized iron, or rust, that is globally distributed by the planet's winds.