Fifty years ago tonight (10:56 EDT), Neil Armstrong stepped onto the surface of the moon. His first words are among the most famous in history:

“That’s one small step for [a] man, one giant leap for mankind.”

It all worked. The landing. The moon walks. The liftoff. The docking with the Command/Service Module commanded by Michael Collins. The return to earth. The reentry. The splashdown.

But what if Apollo 11 had failed?

A month before the moon mission, Apollo 8 astronaut Frank Borman contacted presidential speechwriter William Safire and told him, “You want to be thinking of some alternative posture for the president in the event of mishaps on Apollo 11."

Safire prepared a speech for President Nixon to deliver to the nation if the mission failed. A particular concern was the possibility that liftoff from the moon’s surface would be unsuccessful. The astronauts would be alive but stranded 240,000 miles from earth. There would be no way to save them.

Here are the words never needed, never spoken, only made public 30 years after the mission.

In Event of Moon Disaster

By Bill Safire

Prepared for the President

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.

These two men are laying down their lives in mankind's most noble goal: the search for truth and understanding.

They will be mourned by their families and friends; they will be mourned by the nation; they will be mourned by the people of the world; they will be mourned by a Mother Earth that dared send two of her sons into the unknown.

In their exploration, they stirred the people of the world to feel as one; in their sacrifice, they bind more tightly the brotherhood of man.

In ancient days, men looked at the stars and saw their heroes in the constellations. In modern times, we do much the same, but our heroes are epic men of flesh and blood.

Others will follow, and surely find their way home. Man's search will not be denied. But these men were the first, and they will remain the foremost in our hearts.

For every human being who looks up at the moon in the nights to come will know that there is some corner of another world that is forever mankind.

Safire provided more. His memo to H.R. Haldeman, President Nixon’s chief of staff, concluded with these instructions:

Prior to the President’s Statement: The President should telephone each of the widows-to-be.

After the President’s statement, at the point when NASA ends communications with the men: A clergyman should adopt the same procedure as a burial at sea, commending their souls to "the deepest of the deep, " concluding with the Lord's Prayer.

Fifty years ago tonight, man landed on the moon. President Nixon spoke to Armstrong and Aldrin as they stood on the surface telling them, “Because of what you have done, the heavens have become a part of man's world.”

Fifty years ago this week, NASA excellence brought the men safely home so that “a corner of another world” did not become “forever mankind” and a president’s unspoken words could remain hidden to history for decades to come.