NASA released information Friday that the Mars rover, Curiosity, has been experiencing intermittent short circuits in its robotic arm which could limit its drilling of rocks.

Curiosity is at the base of an 18,000-foot-tall mountain on Mars. Its job is to help scientists figure out how the changes in the rocks at different levels of the mountain have altered the planet’s climate over time. The rocks are made of layers of sediment dating to an era when Mars appeared to have been warm and wet.

The rover seems to be short circuiting in its robotic arm which could limit its drilling of rocks. The first time that sensors picked up this problem, they noticed a surge of current which automatically froze the rover from working while it paused for further commands from Earth. It was in the middle of shaking a sample of rock powder and preparing to transport it to the onboard chemical laboratory.

Curiosity had used the same process in five drilling efforts in 2013 and 2014 without difficulty, according to the New York Times.

The rover had no problems during its first test after the power surge. The second test had the drill repeat the up-and-down motion 180 times with a small surge, lasting a fraction of a second. They were able to pinpoint the most likely location of the short circuit in the coil that generates magnetic fields to move a striker that then hammers the drill.

They do not see the short circuit damaging the $2.5 billion mission. They plan to repeat the tests so that the engineers can better verify the scope and severity. Although the drill would still work even if the hammering apparatus failed, they are concerned that it might not be able to infiltrate harder rocks when needed. But so far, the rocks have been pretty soft.

The mission team plans to resume moving the rover’s arm as early as next week.