Mars Rover Experiences Dust Devil
November 15, 2012

Curiosity Experiences First Dirt Devil On Mars, Analyzes Atmosphere

Lee Rannals for - Your Universe Online

NASA announced on Thursday during a teleconference that its Curiosity rover has experienced its first whirlwind on Mars.

Although the rover did not snap a photo of the whirlwind, Curiosity's Rover Environmental Monitoring Station (REMS) was able to help detect the dust devil.

REMS detected brief dips in air pressure, along with a change in wind direction, leading NASA scientists to determine that there was a whirlwind passing by Curiosity.

Curiosity's instruments are being used to help identify whirlwinds, map winds in relation to slopes, and track daily and seasonal changes in air pressure. NASA is also able to link rhythmic changes in radiation to daily atmospheric changes with the rover's instruments.

"The knowledge being gained about these processes helps scientists interpret evidence about environmental changes on Mars that might have led to conditions favorable for life," NASA said in a prepared statement.

Researchers were able to analyze data from more than 20 atmospheric events during the first 12 weeks after Curiosity landed.

Dust-devil tracks and shadows have been seen from orbit, and have also been captured in images by previous Martian rovers. However, the visual clues have not been seen in Gale Crater.

"Dust in the atmosphere has a major role in shaping the climate on Mars," said Manuel de la Torre Juarez of NASA's Jet Propulsion Laboratory in Pasadena, California. "The dust lifted by dust devils and dust storms warms the atmosphere."

Dominant wind direction identified by REMS has surprised scientist who thought slope effects would produce north-south winds. The rover is sitting just north of a Mount Sharp, and if air movement up and down the mountain's slope governed the wind direction, dominant winds would be north-south. However, the latest data shows east-west winds are dominate.

"With the crater rim slope to the north and Mount Sharp to the south, we may be seeing more of the wind blowing along the depression in between the two slopes, rather than up and down the slope of Mount Sharp," said Claire Newman, a REMS investigator at Ashima Research in Pasadena. "If we don't see a change in wind patterns as Curiosity heads up the slope of Mount Sharp -- that would be a surprise."

The daily cycle of higher pressure in the morning and lower pressure in the evening results from daytime heating of the atmosphere by the sun. As morning ensues, so does a heat-expanded atmosphere.

The effects of the atmospheric tide can be captured by the rover's Radiation Assessment Detector (RAD), which monitor high-energy radiation considered to be health risk to astronauts.

"We see a definite pattern related to the daily thermal tides of the atmosphere," said RAD Principal Investigator Don Hassler of the Southwest Research Institute. "The atmosphere provides a level of shielding, and so charged-particle radiation is less when the atmosphere is thicker. Overall, Mars' atmosphere reduces the radiation dose compared to what we saw during the flight to Mars."

So far, NASA knows that standing next to curiosity, you could tell that the planet definitely has an atmosphere. Its atmosphere is thick enough to have gusty winds, but not thick enough to shield you from ultraviolet light and radiation from space.

During the teleconference, NASA mentioned that Curiosity has now been parked at Rocknest for 40 Martian days. This is the area at which the rover took its first scoops of Martian soil.

NASA said that Curiosity is healthy and doing well, and has recently delivered scoop number 5 to Curiosity's Sample Analysis at Mars (SAM). No further scooping of soil samples is planned at Rocknest, the space agency said.