Apollo: The Race To The Moon

by Catherine Bly Cox

The anomaly that caused the highest pulse rates during Apollo 11 occurred a minute after the landing. It was not mentioned in the press coverage or in the official NASA history, probably because nothing came of it, but for a few minutes it scared the living daylights out of the handful of people on the ground who knew what was happening. On TELMU’s screen in the MOCR and on the lunar module systems screen in SPAN, readings showed that pressure and temperature were rising alarmingly in one of the descent stage’s fuel lines. After the engine had shut down, a blockage had apparently occurred—almost certainly, Grumman’s Tom Kelly in SPAN believed, because liquid helium had frozen a slug of fuel left in the pipe. As they watched the screens, the residual heat from the engine (which had been operating at 5,000 degrees Fahrenheit when the Eagle had landed) was moving up toward the frozen fuel, and the question bothering Kelly was what would happen when the trapped fuel suddenly got much warmer. “There’s no telling what it will do,” he told Low, who by this time was on the phone with Kelly. The fuel was unstable when heated, and Kelly saw a real possibility that the frozen fuel would explode like a small hand grenade.