The Mars rover Curiosity will soon begin to drill into the Red Planet for the first time, mission officials said Tuesday ahead of the highly anticipated endeavor.

Scientists behind the $2.5 billion mission also explained the nature of the small "Martian flower," which had caused a lot of buzz online because it was strikingly different from the surrounding rock.

Aileen Yingst, of the Planetary Science Institute, said that what could have passed as a flower was in fact a relatively large mineral grain or pebble.

"All of these are sedimentary rocks, telling us Mars had environments actively depositing material here," Yingst said. "The different grain sizes tell us about different transport conditions."

Curiosity is traveling toward a flat rock with pale veins that scientists hope will provide clues about any water that might have existed on Mars.

"Drilling into a rock to collect a sample will be this mission's most challenging activity since the (August 6) landing. It has never been done on Mars," said Richard Cook of NASA's Jet Propulsion Laboratory.

"The drill hardware interacts energetically with Martian material we don't control. We won't be surprised if some steps in the process don't go exactly as planned the first time through."

Curiosity will collect samples from inside the "John Klein" rock -- named in honor of a former Mars Science Laboratory deputy project manager who died in 2012 -- and analyze them to determine their chemical and mineral composition.

The rover's cameras have shown several unexpected features on the rock, including veins, nodules, cross-bedded layering, a lustrous pebble embedded in sandstone and possibly some holes in the ground.

The mission, set to last at least two years, aims to study the Martian environment to prepare for a possible future manned mission.

US President Barack Obama has vowed to send humans to the planet by 2030.