Sojourner has made contact with the rock "Yogi" in this false-color image, taken with the Imager for Mars Pathfinder (IMP). The rover's left rear wheel has driven up onto the Yogi's surface in an attempt to get as close as possible to the rock's surface. Sojourner will later use its Alpha Proton X-Ray Spectrometer (APXS) instrument to conduct a study of Yogi's chemical composition.

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 an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (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.