THE SCIENCE OF GATHERING DUST
As the sols slip by on Mars and the rovers do their work, one method of
science investigation will gather dust — and that's a good thing.
The
Magnetic Properties Experiment
on the Mars Exploration
Rover mission will collect dust from the atmosphere and rocks on Mars
for study by the rovers' science instruments. The Viking and Pathfinder
missions established that most of the dust on Mars is magnetic. But
neither mission identified the mineral that causes the magnetism. It is
an important point. Mars is full of oxidized iron. There are magnetic
minerals that can form from the interaction of iron in water. So is
Mars dust chock full of minerals that have been freeze-dried from
ancient water? Or does it contain magnetic minerals that have been left
behind by ancient volcanic processes? Are there a variety of magnetized
minerals? The Mars Rover magnets will try to answer these questions.
Each rover carries three different sets of magnets. Two capture and
filter magnets are located at the front of the rover near the base of
the Pancam mast. A sweep magnet is next to the
Pancam calibration target on the
solar panel deck. Four RAT magnets are located inside the
Rock Abrasion Tool.
The capture magnet is designed to be as strong as possible. It will
attract both strong and weak magnetic dust from the martian atmosphere.
The filter magnet is weaker. These different magnetic strengths allow
scientists to compare the patterns and properties of the dust that
accumulates. As the rovers' move across the martian landscape, the
capture and filter magnets will be examined periodically by the Pancam
camera and Microscopic Imager. When scientists start to see a
significant dust build up, they will use the Mössbauer Spectrometer to
determine the types of iron-bearing minerals that may be present. They
will use the Alpha-Particle-X-Ray Spectrometer (APXS) to determine the
elemental composition of the dust. Spectra from the two science
instruments will reveal what the magnetic particles are made of.
The sweep magnet is a strong, ring-shaped magnet with a center that is
non-magnetic. It will help scientists to determine if the distribution
of microcrystalline minerals from dust particle to dust particle is the
same or different. If it his different, some particles of dust may turn
out to be completely non-magnetic. These are the particles that
scientists are looking for at the center of the sweep magnet. Each time
the Pancam checks its calibration target, it will also image the sweep
magnet so that scientists can see where the dust is collecting and study
any non-magnetic grains.
The RAT magnets will gather magnetic particles from the dust that is
kicked up when the RAT grinds into a martian rock. Pancam images will
be taken of the science tool before and after it works on a rock.
Scientists will be able to compare these images and determine the level
of magnetic material collected.
Each speck of martian dust offers a kernel of knowledge. Learning more
about these magnetic particles will help scientists understand the
ancient processes that created the planet we see today.
Web content editor/writer: Pamela R. Smith
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