Phoenix Microscope Takes First Image of Martian Dust Particle
TUCSON, Ariz. – NASA's Phoenix Mars Lander has taken the first-ever image
of a single particle of Mars' ubiquitous dust, using its atomic force microscope.
The particle -- shown at higher magnification than anything ever seen from
another world -- is a rounded particle about one micrometer, or one millionth
of a meter, across. It is a speck of the dust that cloaks Mars. Such dust
particles color the Martian sky pink, feed storms that regularly envelop
the planet and produce Mars' distinctive red soil.
"This is the first picture of a clay-sized particle on Mars, and the size agrees
with predictions from the colors seen in sunsets on the Red Planet," said
Phoenix co-investigator Urs Staufer of the University of Neuchatel, Switzerland,
who leads a Swiss consortium that made the microscope.
"Taking this image required the highest resolution microscope operated off
Earth and a specially designed substrate to hold the Martian dust," said Tom
Pike, Phoenix science team member from Imperial College London. "We always
knew it was going to be technically very challenging to image particles this small."
It took a very long time, roughly a dozen years, to develop the device that
is operating in a polar region on a planet now about 350 million kilometers
or 220 million miles away.
The atomic force microscope maps the shape of particles in three
dimensions by scanning them with a sharp tip at the end of a spring.
During the scan, invisibly fine particles are held by a series of pits
etched into a substrate microfabricated from a silicon wafer. Pike's
group at Imperial College produced these silicon microdiscs.
The atomic force microscope can detail the shapes of particles as small as
about 100 nanometers, about one one-thousandth the width of a human hair.
That is about 100 times greater magnification than seen with Phoenix's optical
microscope, which made its first images of Martian soil about two months ago.
Until now, Phoenix's optical microscope held the record for producing the most
highly magnified images to come from another planet.
"I'm delighted that this microscope is producing images that will help us
understand Mars at the highest detail ever," Staufer said. "This is proof of the
microscope's potential. We are now ready to start doing scientific experiments
that will add a new dimension to measurements being made by other Phoenix lander
"After this first success, we're now working on building up a portrait gallery of
the dust on Mars," Pike added.
Mars' ultra-fine dust is the medium that actively links gases in the Martian atmosphere
to processes in Martian soil, so it is critically important to understanding Mars'
environment, the researchers said.
The particle seen in the atomic force microscope image was part of a sample scooped
by the robotic arm from the "Snow White" trench and delivered to Phoenix's microscope
station in early July. The microscope station includes the optical microscope, the
atomic force microscope and the sample delivery wheel. It is part of a suite of tools
called Phoenix's Microscopy, Electrochemistry and Conductivity Analyzer.
The Phoenix mission is led by Peter Smith from the University of Arizona with project
management at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and development
partnership at Lockheed Martin, Denver. International contributions come from the
Canadian Space Agency; the University of Neuchatel; the universities of Copenhagen
and Aarhus in Denmark; the Max Planck Institute in Germany; and the Finnish Meteorological
Institute. The California Institute of Technology in Pasadena manages JPL for NASA.
The latest Phoenix images and information are at http://www.nasa.gov/phoenix
Media contacts: Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
Dwayne Brown 202-358-1726
Sara Hammond 520-626-1974
University of Arizona, Tucson