With these words, Armstrong concluded the competition that had gripped the world for years between the two most powerful nations – the United States and the Soviet Union – on Earth and now the Moon. Six and a half hours earlier, he and Edwin “Buzz” Aldrin set their 8-ton spacecraft carefully onto the lunar surface with fewer than 45 seconds of fuel left, fulfilling a promise made eight years before by their martyred president. Stepping onto the Moon, they reached the apex of a perilous journey that in several days would fulfill the president’s second promise – to return them safely to Earth. Their success engaged the work of hundreds of thousands of people and the attentions of billions of people. It was a cosmic and geopolitical culmination that, with the following lunar landings, bears on any future human exploration of space, as we will see.

Armstrong had much on his mind, but his terseness also reflected his characteristic lack of self-absorption. [BOX 2.1] He was selected in part for his steely, split-second ability to make the right choice concerning balky, expensive, and complex flying machines. He had made the right choices in combat, as a test pilot, in Earth’s orbit, in training for lunar landing, and in the landing that day at Tranquility Base, or else he would not have lived to step onto the Moon. He was not easily distracted from the mission. [BOX 2.2]