This view of an American flag on metal recovered from the site of the World Trade Center towers shortly after their destruction on Sept. 11, 2001, was taken on Mars on Sept. 11, 2011, the 10th anniversary of the attacks on the towers. The aluminum component bearing the image of the flag serves as the cable guard of a tool on NASA's Mars Exploration Rover Opportunity. Two cameras on Opportunity recorded exposures during the rover's 2,713th Martian day that were combined into this view.
The cable guard made of metal from the World Trade Center is on Opportunity's rock abrasion tool, which was built and is operated by Honeybee Robotics, New York.
The color portion of the image combines three exposures taken through different filters by Opportunity's panoramic camera to yield approximate true color as the human eye would see it on Mars. The black-and-white portion of the view, providing context, comes from Opportunity's navigation camera.
Opportunity completed its three-month prime mission on Mars in April 2004 and has worked for more than seven years since then in bonus extended missions.
NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for the NASA Science Mission Directorate, Washington.