CAPE CANAVERAL, Fla. (AP) — A NASA rover on Mars has fallen silent as a gigantic dust storm envelops the planet and blots out the sun.

Flight controllers tried late Tuesday night to contact Opportunity, but the rover did not respond. The storm has been growing since the end of May and now covers one-quarter of the planet.

READ MORE: For His 22nd Birthday, Former Gopher Rashod Bateman Bought A Car... For His Mom

Controllers expect it will be several more days before there’s enough sunlight to recharge Opportunity’s battery through its solar panels. NASA says the battery is likely so low that only a clock is still working, to wake the spacecraft for periodic power-level checks.

READ MORE: Most Americans Rank Buying A Home Over Getting Married

NASA launched the twin rovers Opportunity and Spirit in 2003 to study Martian rocks and soil. Spirit hasn’t worked for several years. Opportunity, however, has kept exploring well past its expected mission lifetime.

MORE NEWS: 4 Ex-MPD Officers To Be Tried Together In Federal Case For George Floyd's Death, Judge Rules

(© Copyright 2018 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)