Astrogeology Science Center

Sun-starved Opportunity in 'coma' waiting out the storm

14 June 2018

A massive Martian dust storm has prevented the solar-powered Opportunity rover from going about her daily work as robot field geologist. Dust blocking the sunlight is to blame, and the reason the Mars Explorer Rover is on hiatus. Much like a car needs gas to function, Opportunity needs the sun’s energy to bring her out of deep sleep. But the dust storm has progressed and blotted out the sun’s light to her solar panels.

map of storm

This global map shows the growing dust storm on Mars on June 6, 2018. The map was produced by the Mars Color Imager camera on NASA's Mars Reconnaissance Orbiter spacecraft. The blue dot indicates the aprroximate location of Opportunity.

On June 1, the duststorm was visibly opaque. By June 10, the duststorm covered 14-million square miles of the Red Planet with little sunlight.

This series of images show simulated views of a darkening Martian sky blotting out the Sun from NASA’s Opportunity rover’s point of view, with the right side simulating Opportunity’s current view the global dust storm (June 2018). Image Credits: NASA/JPL-Caltech/TAMU.

Not Quite Nail-biting Worry but Operations Group is Concerned

The team last heard from Opportunity on sol 5111; it is possible that she is in low power fault mode. A low power fault occurs when the sun isn’t capable of providing enough energy to bring the rover out of deep sleep. In deep sleep, the batteries are disconnected, and the mission clock checks daily whether the rover can wake up. If the battery voltage is below 27 V, Opportunity will remain in deep sleep; this could be occurring now. All subsystems are shut down except the mission clock.

“At this point we’re in a waiting mode, listening every day for possible signals from the rover,” said John Callas, Mars Exploration Rover Project Manager.

Opportunity is equipped with heaters in the Rover Electronics Module to keep it warm but the REM temperature must be below -40°C to activate the heaters. Because it is spring, temperatures are not expected to drop this far, so they likely won’t turn on. Should the rover stay warm enough, there is little to fear. Engineers hope the storm will provide some atmospheric insulation against the planet’s dramatic daily temperature swings, Callas said.

Opportunity Team Proud of the Rover--No Matter What

Opportunity has been trekking more than 5000 sols (Mars days) even though it was expected to survive only 90 sols. If Opportunity wakes after the dust storm has abated,  she will be commanded to continue work where she left off—halfway down in "Perseverance Valley" on the west rim of Endeavour Crater—in search of evidence for the valley's origin: water, wind, tectonics, or a combination of all three.  

More information can be found here.

By Janet Richie