October 5, 2016
This graphic indicates a similarity between 2016 (dark blue line) and five past years in which Mars has experienced global dust storms (orange lines and band), compared to years with no global dust storm (blue-green lines and band). The horizontal scale is time-of-year on Mars.
Global dust storms on Mars could soon become more predictable — which would be a boon for future astronauts there — if the next one follows a pattern suggested by those in the past.
A published prediction, based on this pattern, points to Mars experiencing a global dust storm in the next few months. “Mars will reach the midpoint of its current dust storm season on October 29th of this year. Based on the historical pattern we found, we believe it is very likely that a global dust storm will begin within a few weeks or months of this date,” James Shirley, a planetary scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California.
Local dust storms occur frequently on Mars. These localized storms occasionally grow or coalesce to form regional systems, particularly during the southern spring and summer, when Mars is closest to the sun. On rare occasions, regional storms produce a dust haze that encircles the planet and obscures surface features beneath. A few of these events may become truly global storms, such as one in 1971 that greeted the first spacecraft to orbit Mars, NASA’s Mariner 9. Discerning a predictable pattern for which Martian years will have planet-encircling or global storms has been a challenge.
The most recent Martian global dust storm occurred in 2007, significantly diminishing solar power available to two NASA Mars rovers then active halfway around the planet from each other — Spirit and Opportunity.
“The global dust storm in 2007 was the first major threat to the rovers since landing,” said JPL’s John Callas, project manager for Spirit and Opportunity. “We had to take special measures to enable their survival for several weeks with little sunlight to keep them powered. Each rover powered up only a few minutes each day, enough to warm them up, then shut down to the next day without even communicating with Earth. For many days during the worst of the storm, the rovers were completely on their own.”
image credits: NASA JPL-CalTech/MSSS