A Year's Worth of Tracks in the Dust
February 1, 2005
A cable-tie no more than several centimeters (a few inches) long, resembling the wires used to fasten bags around loaves of bread, has left a trail of streaks in a fine layer of dust on the deck of NASA's Mars Exploration Rover Spirit. It is the light-toned squiggle shape against a dark background slightly below and to the right of the center of this image. The tie has been sliding around in a containment bowl created by the solar array and the base of the Pancam Mast Assembly since landing day on Jan. 3, 2004. A low-resolution image from a few hours after landing shows the tie present on the deck. Engineers speculate that the tie may have sprung loose from the bridle that lowered the rover to the surface of Mars or from the rover, lander, backshell, or parachute can. Together, those components used more than 1,000 cable ties, all sterilized like the rover itself to prevent transfer of contaminants from Earth to Mars. Close inspection of the marks in the dust left by the tie reveals that, much like pictographs on a rock wall, older streaks have been covered with dust, while newer streaks are superimposed on the dust that covers the older streaks. Spirit took this picture with its navigation camera on martian day, or sol, 358 (Jan. 3, 2005).