The mast-mounted Stereo Surface Imager (SSI) is essentially a clone of the Mars Pathfinder's whose images gave us an exciting look at the Martian surface in 1997. The SSI provides panoramas of the landing site, and imaging support for other instruments on the lander.

Inside the camera, images are reflected off mirrors into filters before being stored in the camera's memory. The camera can take highly detailed images which allow scientists to accurately measure the sizes of terrain features. With its array of filters, the camera will record the geological composition if the landing site, and the amounts of water and dust in the atmosphere. For the duration of the lander's mission, the SSI will transmit images which will allow scientists to better understand the seasonal climate of Mars.

Functions of the SSI

• Images of Mars
  The SSI can see wavelengths from 0.4 to 1.1 microns, which corespond to the visible spectrum and infrared. The ability to see in the visible range, and an onboard calibration target allows the SSI to take true color images of the Martian surface.
  
  
• Magnetic Measurements
  The SSI will measure the magnetic properties of the Martian surface by comparing the surface to a magnetic calibration target on the lander.
  
  
• Atmospheric Measurements
  By looking at the sun through a narrow view, the SSI can help understand properties of the Martian atmosphere. The images will reveal optical depth of the atmosphere, water vapor, and dust.