NASA has chosen not to use its Curiosity rover to drill into a potential target on Mars due to safety concerns, and instead will have the robot resume its journey to Mount Sharp.

Officials from the space agency said that the target, a pale rock given the name "Bonanza King," was deemed unstable for safe drilling after it moved perceptibly during a test operation, according to Tech Times. A percussion drill was being used in the operation to make a preliminary indentation.

"We have decided that the rocks under consideration for drilling, based on the tests we did, are not good candidates for drilling," said Curiosity Project Manager Jim Erickson of NASA's Jet Propulsion Observatory in Pasadena, Calif.

Erickson added that the team will instead begin driving again toward Mount Sharp, a mountain over three miles high from the center of Mars' Gale Crater, Fox News reported. The goal for Curiosity is to climb up the mountain and along the way record how the environmental conditions of the Red Planet changed over time.

The rover's journey to Mount Sharp began in July 2013, and the robot is still two miles away from reaching its target entry point, which is close to the base of the mountain. Mission officials expect the rover to reach its destination by the end of the year.

Curiosity has faced several obstacles on its journey, with the sharp rocks on Mars' rough surface taking a toll on the robot's wheels, Tech Times reported. It drove through an area called "Hidden Valley" in search of a smoother surface, but its wheels started to slip in sand that was extremely loose. The rover is now looking for a new way to get to the mountain.

"After further analysis of the sand, Hidden Valley does not appear to be navigable with the desired degree of confidence," Erickson said. "We will use a route avoiding the worst of the sharp rocks as we drive slightly to the north of Hidden Valley."

Since landing on Mars in 2012, Curiosity has drilled into three rocks and has made some important discoveries about the planet's environmental conditions, Fox News reported. After studying data collected from the first two drilling operations, mission scientists discovered a lake-and-steam system called Yellowknife Bay that could have been habitable for microbes billions of years ago.