So much for Mars being "The Red Planet".

NASA said Wednesday that its Curiosity rover has scooped up a sample from the interior of a Martian rock and found that the powdery soil just beneath the planet's rust-colored exterior is actually a light gray color.

"Something that the science team is really excited about, is the fact that the tailings from our drill operation aren't the typical rusty orange-red that we associate with just about everything on Mars," said Joel Hurowitz, sampling system scientist for Curiosity.

"When things turn orange, it's because there's a rusting process of some kind going on that oxidizes the iron in the rock," he said during a press conference at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.

NASA said earlier this month that Curiosity had succeeded in obtaining the first sample ever collected from the interior of a rock on another planet, which the JPL scientists hailed as an "historic" breakthrough.

"Seeing the powder from the drill in the scoop allows us to verify for the first time the drill collected a sample as it bore into the rock," said JPL's Scott McCloskey, drill systems engineer for Curiosity.

"Many of us have been working toward this day for years. Getting final confirmation of successful drilling is incredibly gratifying.

"For the sampling team, this is the equivalent of the landing team going crazy after the successful touchdown," he said.

NASA scientists said the hue of the Martian rock, once the sample is subjected to further study, may reveal some intriguing clues about the history and composition of Earth's closest neighbor.

"It may preserve some indication of what iron was doing in these samples without the effect of some later oxidative process that would have rusted the rocks into the orange color that is typical of Mars," Hurowitz told reporters.

The powder was released after the drill on Curiosity's robotic arm bore a 2.5-inch (6.4-centimeter) hole into flat Martian bedrock on February 8.

The rover team plans to have Curiosity sieve the sample and analyze it with instruments aboard the rover.

"Going beyond that surface of the rock gets us behind or under all the environmental exposure that the rest of the top layers of Mars have been seeing," Louise Jandura, sample system chief engineer for Curiosity, said.

"Once we get inside the rock, we get to look at, with our instruments, powder that we bring up that hasn't been affected by some of these other weathering processes."

The sample was taken from a fine-grained, sedimentary rock called "John Klein" -- named in honor of a Mars Science Laboratory deputy project manager who died in 2011.

The rock was selected for the first sample drilling because it may hold evidence of the presence of water long ago.

The $2.5 billion Curiosity mission, set to last at least two years, aims to study the Martian environment -- and hunt for evidence of water -- to prepare for a possible future manned mission.

US President Barack Obama has set a goal of sending humans to the planet by 2030.

Source: AFP