“…Very powdery surface,” he reported back to Houston. “My boot tends to slide over it easily… You have to be careful about where your center of mass is. It takes two or three paces to bring you to a smooth stop. And to change direction you have to step out to the side and cut back a little bit. Like a football player. Moving your arms around doesn’t lift your feet off the surface. We’re not quite that light-footed…”

There was a pressure in his kidneys. He stood still and let go, into the urine collection condom; it was like wetting his pants. Well, Neil might have been the first man to walk on the Moon. But I’m the first to take a leak here.

He looked up. A star was climbing out of the eastern sky, unblinking, hauling its way toward the zenith, directly over his head. It was Apollo, waiting in orbit to take him home.

Armstrong peeled away silver plastic and read out the inscription on the plaque on the LM’s front leg. “First, there’s the two hemispheres of the Earth. Underneath it says, ‘Here Man from the planet Earth first set foot upon the Moon, July 1969 A.D. We came in peace for all mankind.’ It has the crew members’ signatures and the signature of the President of the United States.”

They unfurled the Stars and Stripes. The flag had been stiffened with wire so it would fly there, without any wind.

The two of them tried to plant the pole in the dust. But as hard as they pushed, the flagpole would only go six or eight inches into the ground, and Muldoon worried that the flag would fall over in front of the huge TV audience.

At last they got the pole steady and backed away.

Muldoon set off on some more locomotion experiments.

He tried a slow-motion jog. His steps took him so high that time seemed to slow during each step. On Earth he would descend sixteen feet in the first second of a fall; on the Moon, he would fall only two. So he was suspended in each mid-stride, waiting to come down.

He started to evolve a better way of moving. He bent, and rocked from side to side as he ran. It was more of a lope than a run: push with one foot, shift your weight, land on the other.

He was breathing hard; he heard the hiss of water through the suit’s cooling system, the pipes that curled around his limbs and chest.

He felt buoyant, young. A line from an old novel floated into his mind: We are out of Mother Earth’s leading-strings now…

The capcom’s voice startled him.

“Tranquillity Base, this is Houston. Could we get both of you on the camera for a minute, please?”

Muldoon stumbled to a halt.