CAPE CANAVERAL, Fla. -- A dust storm at Mars is now global, keeping NASA's Opportunity rover out of touch with Earth.
Flight controllers lost contact with the rover more than a week ago. At the time, the dust storm covered one-fourth of Mars. NASA said Wednesday the storm now encircles the red planet, with only tall volcano peaks and the poles exposed to the sun.
Without sunlight, the solar-powered Opportunity can only hunker down and wait for the sky to clear.
NASA's nuclear-powered rover Curiosity is unaffected and is studying the extreme weather conditions. Mars hasn't seen a storm like this since 2007.
Scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, say they remain optimistic Opportunity can survive. The rover has been exploring Mars since 2004.
