| + NASA Homepage+ NASA en Español+ Marte en Español+ Mars Home+ MER Home**Summary**
NASA's twin robot geologists, the Mars Exploration Rovers, will launch                   toward Mars in 2003 in search of answers about the history of water on Mars.

The Mars Exploration Rover mission is part of NASA's Mars Exploration                   Program, a long-term effort of robotic exploration of the red planet.  The                   program seeks to take advantage of each launch opportunity to go to                   Mars, which comes around every 26 months as the planets move                   around the Sun.  Scheduled for two separate launches between June 5                   and July 15, 2003, the two rovers will be delivered in landing craft to                   separate sites on Mars in January 2004.

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 will be targeted to sites that appear to                   have been affected by liquid water in the past.

After the airbag-protected landing craft settle onto the surface and                   open, the rovers will roll out to take panoramic images.  These will give                   scientists the information they need to select promising geological targets                   that will tell part of the story of water in Mars' past.  Then, the rovers will                   drive to those locations to perform on-site scientific investigations over the                   course of their 90-day mission.

These are the primary science instruments to be 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 will                      also 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.  
- **Magnets:**                      for collecting magnetic dust particles. The Mössbauer Spectrometer and                      the Alpha Particle X-ray Spectrometer will analyze the particles                      collected and help determine the ratio of magnetic particles to non-magnetic                      particles. They will 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.                       

A goal for the rover is 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).

Moving from place to place, the rovers will 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 will provide 360-degree, stereoscopic, humanlike views of the                   terrain.  The robotic arm will be capable of movement in much the same                   way as a human arm with an elbow and wrist, and will place instruments directly up against rock                   and soil targets of interest.  In the mechanical "fist" of the                   arm is a microscopic camera that will serve 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.
+ Freedom of Information Act+ The President's Management Agenda+ FY 2002 Agency Performance and                              accountability report+ NASA Privacy Statement, Disclaimer, and                              Accessiblity Certification+ Freedom to Manage                           Last Updated: + Comments and Questions |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|