NASA's twin robot geologists, the Mars Exploration Rovers, launched
toward Mars on June 10 and July 7, 2003, in search of answers about the history of water on Mars. They landed on Mars January 3 and January 24 PST, 2004 (January 4 and January 25 UTC, 2004).
The Mars Exploration Rover mission is part of NASA's Mars Exploration
Program, a long-term effort of robotic exploration of the red planet.
Primary among the mission's scientific goals is to search for and
characterize a wide range of rocks and soils that hold clues to past
water activity on Mars. The spacecraft are targeted to sites on opposite sides of Mars that appear to
have been affected by liquid water in the past. The landing sites
are at Gusev Crater, a possible former lake in a giant impact crater,
and Meridiani Planum, where mineral deposits (hematite) suggest Mars
had a wet past.
After the airbag-protected landing craft settled onto the surface and
opened, the rovers rolled out to take panoramic images. These images give
scientists the information they need to select promising geological targets
that tell part of the story of water in Mars' past. Then, the rovers
drive to those locations to perform on-site scientific investigations.
These are the primary science instruments carried by the rovers:
- Panoramic Camera (Pancam): for determining the mineralogy, texture,
and structure of the local terrain.
- Miniature Thermal Emission Spectrometer (Mini-TES):
for identifying promising rocks and soils for closer examination and for
determining the processes that formed Martian rocks. The instrument is designed to
look skyward to provide temperature profiles of the Martian atmosphere.
- Mössbauer Spectrometer (MB):
for close-up investigations of the
mineralogy of iron-bearing rocks and soils.
- Alpha Particle X-Ray Spectrometer (APXS):
for close-up analysis of the
abundances of elements that make up rocks and soils.
for collecting magnetic dust particles. The Mössbauer Spectrometer and
the Alpha Particle X-ray Spectrometer are designed to analyze the particles
collected and help determine the ratio of magnetic particles to non-magnetic
particles. They can also analyze the composition of magnetic minerals in
airborne dust and rocks that have been ground by the Rock Abrasion Tool.
- Microscopic Imager (MI): for obtaining close-up, high-resolution images
of rocks and soils.
- Rock Abrasion Tool (RAT):
for removing dusty and weathered rock
surfaces and exposing fresh material for examination by instruments onboard.
Before landing, the goal for each rover was to drive up to 40 meters
(about 44 yards) in a single day, for a total of up to one 1
kilometer (about three-quarters of a mile). Both goals have been far exceeded!
Where are the rovers now?
Moving from place to place, the rovers perform on-site geological
investigations. Each rover is sort of the
mechanical equivalent of a geologist walking the surface of Mars. The
mast-mounted cameras are mounted 1.5 meters(5 feet) high
and provide 360-degree, stereoscopic, humanlike views of the
terrain. The robotic arm is capable of movement in much the same
way as a human arm with an elbow and wrist, and can place instruments directly up against rock
and soil targets of interest. In the mechanical "fist" of the
arm is a microscopic camera that serves the same purpose as a
geologist's handheld magnifying lens. The Rock Abrasion Tool serves the purpose of
a geologist's rock hammer to expose the insides of rocks.