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Five Bites Into Mars
NASA's Mars rover Curiosity used a mechanism on its robotic arm to dig up five scoopfuls of material from a patch of dusty sand called "Rocknest," producing the five bite-mark pits visible in this image from the rover's left Navigation Camera (Navcam). Each of the pits is about 2 inches (5 centimeters) wide.The fifth scoopful at Rocknest -- leaving the upper middle bite mark -- was collected during the mission's 93rd Martian day, or sol (Nov. 9, 2012). This image was taken later that same sol. A sample from that fifth scoop was analyzed over the next two sols by Curiosity's Sample Analysis at Mars (SAM) suite of instruments inside the rover. A second sample from the same scoopful of material was delivered to SAM for analysis on Sol 96 (Nov. 12). No further scooping of soil samples is planned at Rocknest.
The first Rocknest scoop was collected during Sol 61 (Oct. 7). Fine sand and dust from that scoopful and two subsequent ones were used for scrubbing the inside surfaces of chambers in the sample-handling mechanism on the arm. Samples from scoops three, four and five were analyzed by the Chemistry and Mineralogy instrument inside the rover.
Image credit: NASA/JPL-Caltech
Thermal Tides at Mars
This diagram illustrates Mars' "thermal tides," a weather phenomenon responsible for large, daily variations in pressure at the Martian surface. Sunlight heats the surface and atmosphere on the day side of the planet, causing air to expand upwards. At higher levels in the atmosphere, this bulge of air then expands outward, to the sides, in order to equalize the pressure around it, as shown by the red arrows. Air flows out of the bulge, lowering the pressure of air felt at the surface below the bulge. The result is a deeper atmosphere, but one that is less dense and has a lower pressure at the surface, than that on the night side of the planet. As Mars rotates beneath the sun, this bulge moves across the planet each day, from east to west. A fixed observer, such as NASA's Curiosity rover, measures a decrease in pressure during the day, followed by an increase in pressure at night. The precise timing of the increase and decrease are affected by the time it takes the atmosphere to respond to the sunlight, as well as a number of other factors including the shape of the planet's surface and the amount of dust in the atmosphere.Image credit: NASA/JPL-Caltech/Ashima Research/SWRI
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 that 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 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, a division of the California Institute of Technology in Pasadena,
manages the project for NASA's Science Mission Directorate, Washington,
and built Curiosity.
For more information about Curiosity and its mission,
visit: http://www.nasa.gov/msl
You can follow the mission on Facebook and Twitter at: http://www.facebook.com/marscuriosity
Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov
Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov
NASA
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov
Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov
NASA
Guillermo Gonzalo Sánchez Achuteguui
ayabaca@hotmail.com
ayabaca@gmail.com
ayabaca@yahoo.com
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