Fifty years ago, Apollo 16 almost didn’t land on the Moon.
On April 20, 1972, two spacecraft danced in tight formation, high above a ubiquitous gray and tan lunar landscape. Aboard the Lunar Module (callsign Orion), astronauts John Young and Charlie Duke steeled themselves for a tricky descent to land in the Moon’s rugged, equator-hugging mountains, 30 miles (48 kilometers) north of the worn crater, Descartes. Sampling the lunar highlands, it was hoped, might yield volcanic rocks and insights into the Moon’s past.
Fate, though, had another card to play. Inside the Command/Service Module (callsign Casper), piloted by Ken Mattingly, all was not well. After undocking from Orion, Mattingly had to adjust his ship’s orbit around the Moon from elliptical to circular for three days of surface observations. To do that, he needed to fire Casper’s engine. But when Mattingly tested its controls, the ship unexpectedly shuddered, as if he was riding down a rickety railroad track.
It was unwelcome news. If Casper’s engine was damaged, hopes of Young and Duke landing on the Moon would evaporate. And two years after the near-disaster of Apollo 13, any whiff of failure could prompt nervous politicians and a jittery NASA top brass to cancel the sole remaining lunar voyage, Apollo 17.
Apollo 16 makes it to the Moon
Back in 1970, Young, Duke, and Jack Swigert were Apollo 13’s backup crew when Duke caught German measles. Since the backups worked closely with prime crewmen Jim Lovell, Fred Haise, and Mattingly, both crews risked infection. Mattingly lacked immunity to measles, and fearful that he might get sick in space, NASA opted to go with Swigert instead. A year later, Young, Duke, and Mattingly were tapped for Apollo 16.
But illness was never far away. Shortly before launch, Duke came down with bacterial pneumonia and doctors found elevated levels of bilirubin (a possible indicator of hepatitis) in Mattingly’s blood. Both men were cleared to fly. But on launch morning, April 16, 1972, Haise couldn’t resist one final prank. As Duke climbed into the spacecraft, teetering atop the 36-story Saturn V rocket, he spotted a note taped to his seat. In Haise’s handwriting, it read: “Welcome, Typhoid Mary.”
Apollo 16’s four-day trek to the Moon proved uneventful. But after Orion and Casper parted company in lunar orbit, the engine glitch stalled everything. They flew in formation for four hours as Mission Control figured out a solution.