The death of Walter Cronkite and the vivid memories it evokes of his coverage of the Gemini and Apollo missions of the 1960s and early 1970s, serves as a reminder that Monday will mark the fortieth anniversary of the arrival of the Apollo 11 lunar module on the moon and of the moment that Neil Armstrong’s foot touched its powdery surface and he uttered the words, “One small step…”

Armstrong has always kept a low profile in the succeeding decades and he doesn’t plan to change it now. On Sunday night he will talk for 15 minutes at the Smithsonian’s Air and Space Museum, but the institition’s spokesperson was quick to inform the media that no interviews or pictures would be permitted. By contrast, Edwin “Buzz” Aldrin, always the most visible member of the three-man crew, has been vigorously pressing the argument that NASA’s ongoing plans to establish a permanent presence on the moon in the next decade represent a dead end. In an op-ed that appeared in the Washington Post and other newspapers on Thursday, he maintains that America should set its eye instead on Mars.

Aldrin will be at the Smithsonian tomorrow, too, as will Apollo 11’s command module pilot, Michael Collins. (A report from the AP states that all three will also meet at the White House with President Obama on Monday, as they once met President Nixon in the Pacific moments after splashing down to Earth.)

Collins is the author of the 1974 book Carrying The Fire, one of the most thoughtful and profound of American autobiographies, for which Charles Lindbergh wrote the foreword. In the decade after Apollo 11, he was the director of the National Air and Space Museum, but in the last twenty years has been less visible. But a statement he issued this month through NASA, as quoted in the AP article above, makes it clear that the concerns about the future of the planet that he expressed in the 1970s are still on his mind today.

The Guardian has just published an article about Collins which describes the terrible responsibility which was uniquely his during the Apollo 11 mission. Although the lunar module had repeatedly been tested and allowances made for its performance in the weightless atmosphere and lighter gravity of the moon, no one at NASA, or anywhere else, could be completely sure that the trip to the moon’s surface would conclude successfully.

Neil Armstrong, coolly assessing the situation before liftoff, thought that the chances were about 50-50 that the lunar module would not be able to escape the moon’s gravitational pull and that he and Aldrin would either crash back to the surface or, perhaps, would be stranded in an orbit far below the capacity of the command module to help, until their oxygen ran out. There were eighteen separate rescue plans devised, but there was no guarantee that any of them would work if needed.

Collins agreed with Armstrong’s view of the risks. As the world listened to Armstrong and Aldrin announce that “the Eagle has landed” and then watched them walk from their module, Collins remained in orbit, well aware that if worst came to worst, he would return to Earth alone, always to be, in his words, “a marked man.” Later, Charles Lindbergh, who spent thirty hours alone over the Atlantic, would observe that Collins, for a similar duration, had experienced the most profound isolation a human being had ever known until then.

At the White House, there were similar worries. Frank Borman, the commander of the Apollo 8 mission which was the first to orbit the moon, advised the White House that the President should be prepared to speak to the nation if Apollo 11 ended in tragedy. Nixon speechwriter William Safire therefore was assigned to draft a speech for this contingency that read, in part:

“Fate has ordained that the men who went to the Moon to explore in peace will stay on the Moon to rest in peace. These brave men, Neil Armstrong and Edwin Aldrin, know that there is no hope for their recovery. But they also know that there is hope for mankind in their sacrifice.”

(Over the last few weeks the text of this address-that-never-was has been mentioned in some websites and news reports as if it were recently unearthed, but in fact it’s been part of the historical record since Safire discussed and quoted from it in his 1975 book Before The Fall.)

I was 11 when Apollo 11 reached the moon and can well remember those grainy black-and-white images which amazed and stirred my whole family in the middle of the night. It was truly a time of wonder. And of thankfulness when Armstrong, Aldrin and Collins were safely back on Earth.