[meteorite-list] Curiosity Rover Providing New Weather and Radiation Data About Mars

[Ron Baalke]

Nov. 15, 2012

Dwayne Brown 
Headquarters, Washington          
202-358-1726 
dwayne.c.brown at nasa.gov 

Guy Webster 
Jet Propulsion Laboratory, Pasadena, Calif. 
818-354-6278 
guy.webster at jpl.nasa.gov 

RELEASE: 12-402

NASA ROVER PROVIDING NEW WEATHER AND RADIATION DATA ABOUT MARS

PASADENA, Calif. -- Observations of wind patterns and natural 
radiation patterns on Mars by NASA's Curiosity rover are helping 
scientists better understand the environment on the Red Planet's 
surface. 

Researchers using the car-sized mobile laboratory have identified 
transient whirlwinds, mapped winds in relation to slopes, tracked 
daily and seasonal changes in air pressure, and linked rhythmic 
changes in radiation to daily atmospheric changes. The knowledge 
being gained about these processes helps scientists interpret 
evidence about environmental changes on Mars might have led to 
conditions favorable for life. 

During the first 12 weeks after Curiosity landed in an area named Gale 
Crater, an international team of researchers analyzed data from more 
than 20 atmospheric events with at least one characteristic of a 
whirlwind recorded by the Rover Environmental Monitoring Station 
(REMS) instrument. Those characteristics can include a brief dip in 
air pressure, a change in wind direction, a change in wind speed, a 
rise in air temperature or a dip in ultraviolet light reaching the 
rover. Two of the events included all five characteristics. 

In many regions of Mars, dust-devil tracks and shadows have been seen 
from orbit, but those visual clues have not been seen in Gale Crater. 
One possibility is that vortex whirlwinds arise at Gale without 
lifting as much dust as they do elsewhere. 

"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 (JPL) in Pasadena, Calif. He is the investigation 
scientist for REMS, which Spain provided for the mission. "The dust 
lifted by dust devils and dust storms warms the atmosphere." 

Dominant wind direction identified by REMS has surprised some 
researchers who expected slope effects to produce north-south winds. 
The rover is just north of a mountain called Mount Sharp. If air 
movement up and down the mountain's slope governed wind direction, 
dominant winds generally would be north-south. However, east-west 
winds appear to predominate. The rim of Gale Crater may be a factor. 

"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." 

REMS monitoring of air pressure has tracked both a seasonal increase 
and a daily rhythm. Neither was unexpected, but the details improve 
understanding of atmospheric cycles on present-day Mars, which helps 
with estimating how the cycles may have operated in the past. 

The seasonal increase results from tons of carbon dioxide, which had 
been frozen into a southern winter ice cap, returning into the 
atmosphere as southern spring turns to summer. 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 
works its way westward around the planet, so does a wave of 
heat-expanded atmosphere, known as a thermal tide. 

Effects of that atmospheric tide show up in data from Curiosity's 
Radiation Assessment Detector (RAD). This instrument monitors 
high-energy radiation considered to be a health risk to astronauts 
and a factor in whether microbes could survive on Mars' surface. 

"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's Boulder, Colo., branch. "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." 

The overall goal of NASA's Mars Science Laboratory mission is to use 
10 instruments on Curiosity to assess whether areas inside Gale 
Crater ever offered a habitable environment for microbes. 

JPL manages the Mars Science Laboratory Project for NASA's Science 
Mission Directorate in Washington. JPL also built Curiosity. 

For more about the mission, visit: 

http://www.nasa.gov/msl 

You can follow the mission on Facebook and Twitter at: 

http://www.facebook.com/marscuriosity 

and 

http://www.twitter.com/marscuriosity 
	
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