Kennedy's deadline: "by the end of the decade" was crucial. It became "the president's deadline" and everyone rallied to fulfil it.
A human Mars mission now is comparatively less difficult than the challenge that Apollo faced, with far superior technology, knowledge and funding. NASA has become a constituency-driven project rather than mission-driven. Mind you, it's doing great stuff still with the robotic exploration program, but undertaking a deep-space human mission involves the kind of determination a bureaucracy on autopilot is just not capable of.
NASA is also more than anything a creature of the President and could respond to such a challenge once more, given the chance.
A human Mars mission now is comparatively less difficult than the challenge that Apollo faced, with far superior technology, knowledge and funding. NASA has become a constituency-driven project rather than mission-driven. Mind you, it's doing great stuff still with the robotic exploration program, but undertaking a deep-space human mission involves the kind of determination a bureaucracy on autopilot is just not capable of.
NASA is also more than anything a creature of the President and could respond to such a challenge once more, given the chance.