US Space Agency NASA's Mars rover 'Opportunity' was on Wednesday threatened by a massive dust storm that engulfed the red planet and put the unmanned, solar-powered vehicle into sleep mode.
The severe dust storm blocked out the Sun over one-quarter of the Mars, blanketing an area spanning 35 million square kilometers, reported NASA.
"Opportunity, located in a spot called Perseverance Valley has fallen asleep and is waiting out of the storm", said NASA officials. The officials added that they are hopeful that the storm will be cleared and they would be able to communicate with the rover.
The storm was first detected on May 30 and grew worse in recent days.
The rover, one of the two currently operating on the Mars, has shut down everything except its master clock, and last communicated with the Earth on June 10.
'Opportunity' along with his twin named 'Spirit' was launched in 2003. Both of them landed on Mars a year later to probe the signs of past life. Since then, the rover has made a number of discoveries about the Red Planet, including the evidence that the planet had stayed wet for an extended period and that conditions could have been suitable for sustaining microbial life.
At the time of the storm, 'Opportunity' was circling around a surrounding channel, craved in the rim of the crater, to see if it might have been created by flowing water or wind erosion.
Its twin, 'Spirit', became stuck on the planet in 2009 and the mission was formally declared over in 2011.
However, NASA officials are hopeful that 'Opportunity' will not fully shut down because of the approaching Martian summer where the temperature is expected not to drop below the rover's minimal operating temperature, i.e. -55 degree Celsius.
So far 'Opportunity' has travelled 45 kilometers on the Martian surface. Well, this is not the first time that the rover has encountered a dust storm. It had survived a less severe dust storm back in 2007.