MOM Captures Mars Storm
The Mars Orbiter Mission from the Indian Space Research Organization has started off its work at the Red Planet by storm. No, seriously — it captured a view of a regional dust storm over the northern part of Chryse Planitia (the regions of Mars where Viking 1 and the Pathfinder missions landed). This remarkably clear image was taken on September 28th as part of the mission’s early science work.
Global dust storms are an important part of the Martian climate system. The first spacecraft to directly image one was Mariner 9, which arrived in 1971 and had to wait for nearly a month before it could return surface images of the planet. Today we know that dust storms, particularly regional and global storms occur most often when the planet is at or near perihelion (closest to the Sun in its orbit). This makes sense, since the increased heat the planet gets at that time helps kick these storms up.
During a Martian dust storm, the winds send sand grains skipping across the surface, as well as blowing dust up into the air. You may have seen images and animations of dust devils on Mars — these are small, localized “tornadoes” that whirl across the surface and kick up dust. Dust storms are much larger, and cover huge regions and alternately scour the surface of dust and then redeposit it elsewhere. Most of the dust storms we see on Mars (except for the very large-scale or global ones) cover an area of the surface for a short time (typically a few days). The winds range in speed from about 50 to 100 kilometers per hour (30 to 65 miles miles per hour).
Martian dust storms are a fact of life on the Red Planet, something our landers can be affected by as clouds of dust and swarms of sand blast past them. The Mars Exploration Rover teams noticed a big effect when the battery power on Spirit and Opportunity dropped during and after dust storm. This happened because dust particles settled onto the solar arrays, partially blocking sunlight. As luck would have it, dust devils later whirled over the rovers and cleared off their panels.
In the future, when humans are exploring Mars, knowledge of dust devils will help them plan expeditions and get themselves to safety. Images like these and others provided by orbiting spacecraft will provide an early warning system for them.