The IBM RAD6000 radiation hardened single board computer, now produced by BAE Systems, was initially developed in a collaboration with the Space Electronics and Protection Branch and IBM Federal Systems and is now used on nearly 200 satellites and robotic spacecraft, including on the twin Mars Exploration Rovers—"Spirit" and "Opportunity". In November 2005, the AFRL XSS-11 satellite demonstrator received Popular Science's "Best of What's New" award in the Aviation and Space category. The Space Vehicles Directorate is also a leading collaborator in the Department of Defense Operationally Responsive Space Office's Tactical Satellite Program and served as program manager for the development of TacSat-2, TacSat-3, and is current program manager for the development of TacSat-5. They also have contributed experimental sensors to TacSat-4 which is managed by the NRL's Center for Space Technology.