Salty Expression (False Color)
Date: 12 Jan 2006

NASA's Mars Exploration Rover Spirit spent 2006's Martin Luther King, Jr. holiday weekend analyzing a remarkable exposure of bright, loose material. Spirit discovered the material while driving toward "Home Plate" along the floor of the basin south of "Husband Hill" in Gusev Crater. These images from Spirit's panoramic camera (Pancam) show some of the most colorful deposits photographed on the surface of Mars.


Spirit uncovered several types of materials distinctive in their color, physical properties and chemistry as a result of accidentally digging a trench 30 cm (11.8 inches) wide during a turn at the end of a drive. The white material in this image is brighter than any seen previously by the rover. It has a powdery and cloddy texture and exhibits a high abundance of salts. The materials appear similar in some ways to bright soil deposits seen back at the "Paso Robles" site that Spirit encountered on the rover's Martian day, or sol, 431 (20 March 2005) while climbing the northern flank of "Husband Hill."


Spirit analyzed the bright, yellowish exposures in the lower left part of the frame using instruments on the rover's robotic arm. Scientists hypothesized and then confirmed that these materials have a salty chemistry dominated by iron-bearing sulfates. These salts may record the past presence of water, as they are most easily mobilized and concentrated in liquid solution. Spirit also examined the unusual, pitted rock about 10 cm (4 inches) wide in the lower center of the frame.


This view is a false-color composite combining images taken with the Pancam's 750-nm, 530-nm and 430-nm filters on 12 Jan. 2006, the rover's 721st sol on Mars.


Last Update: 22 Nov 2011 (AMB)

Credit: NASA/JPL/Cornell