Mars, the red planet, could experience a global dust storm in a thick haze in coming months, US space agency NASA has predicted.
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.
"Mars will reach the midpoint of its current dust storm season on October 29 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 NASAs Jet Propulsion Laboratory (JPL) in California.
Local dust storms occur frequently on Mars. These localised 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 JPLs 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," said Callas.
Dust storms also will present challenges for astronauts on the red planet. Although the force of the wind on Mars is not as strong as portrayed in an early scene in the movie "The Martian," dust lofted during storms could affect electronics and health, as well as the availability of solar energy.
Mars has been observed shrouded by planet-encircling dust nine times since 1924, with the five most recent planetary storms detected in 1977, 1982, 1994, 2001 and 2007.
The actual number of such events is no doubt higher. In some of the years when no orbiter was observing Mars up close, Mars was poorly positioned for Earth-based telescopic detection of dust storms during the Martian season when global storms are most likely.
(With inputs from PTI)
