Mr. Aldrin held the camera and pointed it at an exhausted, satisfied Neil Armstrong. His look says a lot about the culmination of a man's — and a nation's — work. There was no certainty that this mission would succeed. President Richard Nixon, who famously talked to the astronauts while they walked the moon's surface, had a prepared speech memorializing the astronauts who would not return to Earth, just in case. After all, it was only 21/2 years earlier that Gus Grissom, Ed White and Roger Chaffee burned to death inside the locked Apollo command capsule when a spark ignited the combustible pure oxygen atmosphere surrounding them. Few thought that, 30 months later, their fellow astronauts would make it to the moon. And that a relieved Neil Armstrong would be able to smile for Mr. Aldrin's camera with the knowledge that the United States had accomplished what was once thought impossible, or even folly.