Down to 14.4 km — and a tumble out of control

After entering lunar orbit, Stafford and Cernan undocked Snoopy from Charlie Brown — making John Young the first person left alone in orbit around another world. Snoopy then descended to within 14.4 kilometres of the surface of the Sea of Tranquility, where Apollo 11 was to land two months later.

To make sure the crew could not give in to temptation and land, Snoopy’s ascent stage was deliberately loaded with only as much fuel as would remain AFTER a launch from the Moon — not enough for an actual landing. “A lot of people thought about the kind of people we were: don’t give those guys an opportunity to land, ’cause they might!” Cernan recalled. During the low pass, Stafford described the future Apollo 11 landing site as smoother than he had expected.

While preparing to jettison the descent stage, Snoopy suddenly began to gyrate out of control. Cernan swore into a hot mic being broadcast live — which, along with other language from the crew, drew complaints back home. The cause was a guidance-mode switch that both men had accidentally flipped back to its original position. Stafford brought the crisis under control within seconds using manual piloting and saved the module.