Astronomers expected dust storms to kick up on the planet Mars sometime this year. That’s because such storms typically occur in years when Mars is near its perihelion, or closest point to the sun, an event that happens every 687 Earth-days as Mars orbits the sun. The next Mars perihelion will be September 16, 2018. Then Mars – whose orbit is much more elliptical than that of Earth – will be receiving 40% more sunlight than when the planet is farthest from the sun. But already a dust storm is raging on Mars. Scientists who’ve been tracking it since at least early June said in a statement that it’s:
… one of the thickest dust storms ever observed on Mars … The storm has caused NASA’s Opportunity rover to suspend science operations.
The dust storm is raging above and around Opportunity, which is solar powered, and NASA has not heard from the rover since Tuesday. The dust won’t topple the rover, but it has hidden the sun, creating what Mars Exploration Rover project manager John Callas said at a Wednesday media telecon was a “spacecraft emergency.” Callas said his team was assuming the charge in Opportunity’s batteries has dipped below 24 volts. If so, the rover has entered a low-power fault mode, when all subsystems except the mission clock are turned off.
So Opportunity’s fate is unknown at this time, although there’s some possibility the rover might be able to wait it out.
— Alan Boyle (@b0yle) June 13, 2018
Meanwhile, the dust storm is still growing. In fact, it now blankets some 14 million square miles (35 million square km) of Martian surface — about a quarter of the planet, NASA said, adding:
Dust storms are a frequent feature on Mars, occurring in all seasons. Occasionally, they can balloon into regional storms in a matter of days, and sometimes even expand until they envelop the planet. These massive, planet-scaled storms are estimated to happen about once every three to four Mars years (six to eight Earth years); the last one was in 2007. They can last weeks, or even months at the longest …
The thin atmosphere makes these storms vastly different from anything encountered on Earth: Despite the drama of “The Martian”, the most powerful surface winds encountered on Mars would not topple a spacecraft, although they can sand-blast dust particles into the atmosphere.
NASA scientists say they welcome this opportunity to study aMartian dust storm. Jim Watzin, director of NASA’s Mars Exploration Program at the agency’s headquarters in Washington, commented:
This is the ideal storm for Mars science. We have a historic number of spacecraft operating at the red planet. Each offers a unique look at how dust storms form and behave – knowledge that will be essential for future robotic and human missions.
NASA has three orbiters circling the red planet, each equipped with special cameras and other atmospheric instruments. And it has two operating rovers on Mars’ surface, if you count Opportunity. The other rover, Curiosity, has a nuclear-powered battery. That means it doesn’t face the same risk as the solar-powered Opportunity.
Other nations have spacecraft at Mars as well. I’m counting eight total current missions at Mars at Wikipedia’s list of missions to Mars page, with a ninth mission, Insight Mars, launched as recently as May 5 and heading for a November 2018 landing on Mars.
Since 2007, Mars scientists have been patiently waiting for a planet-encircling dust event – less precisely called a “global” dust storm, though the storms never truly cover the entire globe of Mars. In 1971, one of these storms came close, leaving just the peaks of Mars’ Tharsis volcanoes poking out above the dust.
The most recent dust storm is the earliest ever observed in the northern hemisphere of Mars, said Bruce Cantor of Malin Space Science Systems, deputy principal investigator for the Mars Color Imager. But it could take several more days before anyone can tell whether the storm is encircling the planet.
If it does “go global,” the storm will offer a brand new look at Martian weather. Four [NASA] spacecraft stand ready to collect the science that shakes out.
Bottom line: A giant dust storm has been building on Mars throughout June 2018, and now covers a quarter of the planet. The Opportunity rover has suspended science operations.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.