Mars' outermost natural satellite, Deimos, is seen from the planet's surface in this Pathfinder image taken at night on Sol 4. This picture was acquired by the Imager for Mars Pathfinder (IMP) camera. Using IMP images of Deimos and its companion moon Phobos, the spectral characteristics of the satellites and properties of the Martian atmosphere are determined.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Photojournal note: Sojourner spent 83 days of a planned seven-day mission exploring the Martian terrain, acquiring images, and taking chemical, atmospheric and other measurements. The final data transmission received from Pathfinder was at 10:23 UTC on September 27, 1997. Although mission managers tried to restore full communications during the following five months, the successful mission was terminated on March 10, 1998.