The global dust storm that has raged on Mars for more than a month is beginning to subside, according to observations by orbiters circling the Red Planet as well as by NASA’s Curiosity rover.
According to scientists monitoring the storm, more dust has been falling to the planet’s surface than being raised into its atmosphere since July 23.
NASA’s Mars Reconnaissance Orbiter (MRO) recorded that temperatures in the middle section of Mars’s atmosphere have stopped rising. Warming in this part of the atmosphere is caused by dust particles absorbing solar heat, so a halt in that warming indicates levels of atmospheric dust are falling.
Both MRO’s Mars Color Imager (MARCI), a wide-angle-camera, and its Mars Climate Sounder (MCS), an instrument that profiles temperature, picked up signs of the diminishing storm.
Their data is corroborated on the ground by Curiosity, which has also detected dust levels declining at its location in the 96-mile- (154-km-) wide Gale Crater. Because Curiosity is nuclear-powered, it does not rely on solar panels and has been able to continue operating during the storm.
“It’s the beginning of the end for the planet-encircling dust storm on Mars,” noted a NASA statement released on Thursday, July 26.
Several surface features and Martian land forms that were obscured by dust for weeks are again becoming visible to orbiters, the statement added.
Scientists hope the storm will die down enough for Earth-based telescopes to view these features, as Mars is currently making its closest approach to Earth since 2003.
NASA’s 15-year-old Opportunity rover, which relies on solar panels to power its batteries, put itself into hibernation mode in June when the storm intensified and has not contacted Earth since June 10.
Members of Opportunity’s mission team, who listen daily for signals from the rover, are hopeful it will survive and eventually reawaken, as temperatures at its location in the 14-mile- (22-km-) wide Endeavor Crater never fell low enough to freeze it.
At the same time, they acknowledge the rover could take several weeks or even months to contact Earth again because the Martian skies need to be clear enough for its solar panels to recharge its batteries.