The New Yorker:

How Apollo 13 got lost in space—then made it back.

By Henry S. F. Cooper, Jr.

At a little after nine Central Standard Time on the night of Monday, April 13, 1970, there was, high in the western sky, a tiny flare of light that in some respects resembled a star exploding far away in our galaxy. At the Manned Spacecraft Center, near Houston, Texas, the glow was seen by several engineers who were using a rooftop observatory to track the Apollo 13 spacecraft, which had been launched two days before and was now a day away from the moon and two days from a scheduled moon landing. One of the group, Andy Saulietis, had rigged a telescope to a television set in such a way that objects in the telescope’s field of view appeared on the screen. Above, the sky was clear and black, like deep water, with occasional clouds making ripples across it. Saulietis and his companions—who, incidentally, had no operational connection with the Apollo 13 mission but were following it for a related project—had lost sight of the spacecraft, two hundred and five thousand miles away. However, they had been watching the booster rocket that had propelled the spacecraft out of earth orbit and was trailing it to the moon; the booster had appeared as a pinprick of light that pulsed slowly, like a variable star, for it tumbled end over end as the result of dumping its fuel, and the sunlight glinted off it with varying intensity. Shortly before nine, the observers on the rooftop at Houston had lost track of the booster, for the pinprick had been almost at the limit of the resolving power of their equipment. Suddenly, near the middle of the TV screen, a bright spot appeared, and over the next ten minutes it grew to be a white disc the size of a dime. The rooftop watchers had no communications link with the Mission Control Center, about two hundred yards away—a large building consisting of two linked wings, with operations rooms in one, offices in the other—and they had no reason to connect the flaring light with the spacecraft or to be concerned with the safety of its crew—Captain James A. Lovell, Jr., of the United States Navy, who was in command, and the pilots for the command and lunar modules, John L. Swigert, Jr., and Fred W. Haise, Jr., both civilians. It was to be some time before either Mission Control—which had no telescopic means of watching Apollo 13—or the astronauts themselves realized that one of the ship’s two oxygen tanks had burst, spewing into space three hundred pounds of liquid oxygen, which meant the loss of half the craft’s supply of this element for generating electricity and water. 

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