Any allergy sufferer will tell you that dust can be a killer. But those dust bunnies under the couch have nothing on the planet-wide storms that periodically engulf Mars in late spring and early summer.
—Image courtesy NASA, J. Ball (Cornell), M. Wolff (SSI), and the Hubble Heritage Team (STScI/AURA)
Such storms are kind of a big deal to the twin Mars rovers Spirit and Opportunity, which rely on well-lit solar panels to keep themselves running.
A couple summers ago, dust blocked more than 99 percent of direct sunlight reaching the rovers and nearly spelled doom for the plucky robots, which have been toiling away on Mars since 2001.
To try and stay ahead of the curve, the rovers each point a camera toward the sun every day to check for atmospheric clarity, allowing researchers on Earth to adjust the bots' power needs.
Spirit goes into stealth mode?
—Image courtesy NASA/JPL-Caltech/ Cornell
The rovers get some extra help from the Mars Reconnaissance Orbiter, which—among its many talents—can act like a weather satellite and track dust storms from the sky.
"We can identify where dust is rising into the atmosphere and where it is moving from day to day," Michael Malin of Malin Space Science Systems, which operates one of the orbiter's cameras, said in a NASA statement.
Such knowledge is key, as science missions can get interrupted or delayed if there's even a hint that an oncoming storm will drain power reserves.
The orbiter's "weather reports" in recent weeks "have let us be more aggressive about using the rovers," Mark Lemmon, a rover-team atmospheric scientist, said in the statement.
"There have been fewer false alarms. Earlier in the mission, we backed off a lot on operations whenever we saw a small increase in dust. Now, we have enough information to know whether there's really a significant dust storm headed our way."
—Image courtesy NASA/JPL-Caltech/MSSS
The latest composite image shows almost the whole globe, with billowing clouds of dust being lifted into the air by a storm near the south polar ice cap. (The blurry bits running vertical in the image aren't dust, fyi, but an effect of the camera's viewing geometry.)
Luckily the same wild winds that churn up the occasional dust storm also help clean particles that accumulate on the rover's solar panels. According to NASA, the rovers would have died years ago from dusty buildup if it wasn't for these regular wipe-downs.
Bill Nelson, the rovers' engineering chief, said that this spring "we're all hoping we'll get another good cleaning."
