When the first man on the moon died Saturday, U.S. President Barack Obama tweeted: "Neil Armstrong was a hero not just of his time, but of all time." Armstrong's final comment on Obama, on the other hand, was that the president's policy on manned space flight was "devastating," adding that it condemned the United States to "a long downhill slide to mediocrity."

That was two years ago, when three Americans who had walked on the Moon, Neil Armstrong, James Lovell, commander of Apollo 13, and Eugene Cernan, commander of Apollo 17, published an open letter to Obama pointing out that his new space policy effectively ended American participation in the human exploration of deep space.

Armstrong was famously reluctant to give media interviews. It took something as hugely shortsighted as Obama's cancellation of the Constellation program in 2010 to make him speak out in public. But when he did, he certainly did not mince his words. "We will have wasted our current $10 billion-plus investment in Constellation," he said, "and equally importantly, we will have lost the many years required to recreate the equivalent of what we will have discarded. For the United States ... to be without carriage to low Earth orbit and with no human exploration capability to go beyond Earth orbit ... destines our nation to become one of second- or even third-rate stature."