An experiment illustrating two rovers cooperatively exploring a field site was performed at Black Rock Summit, Nevada, in May 2000. The rovers FIDO and K9 are mechanically identical prototype planetary rovers designed at the Jet Propulsion Laboratory. FIDO carried high-resolution false-color infrared and low-resolution monochrome stereo cameras and an infrared point spectrometer on a mast-mounted pointable platform, a manipulator arm equipped with a color microscopic imager, and a coring drill for sample collection. K9 carried on a mast-mounted pointable platform high-resolution color and low-resolution monochrome stereo cameras, and a Laser Induced Breakdown Spectrometer for standoff elemental analysis. A team located at Jet Propulsion Laboratory commanded the two rovers for 3 days. K9 obtained stereo images of targets, and three-dimensional models were constructed to determine the best locations for FIDO to obtain core samples. A drilling target was selected 1.5 m from the starting position of FIDO. Six command cycles and 2 m of traversing were required for FIDO to reach, drill into, and place an instrument on the target. K9 required 11 command cycles to traverse 60 m and obtain full-coverage stereo images of two rock targets along its route. Virtual reality-based visualization software called Viz provided situational awareness of the environment for both rovers. Commands to K9 were planned using Viz, resulting in improved rover performance. The results show that two rovers can be used synergistically to achieve science goals, but further testing is needed to completely explore the value of two-rover missions.