A slip of the fingers

On one occasion, while Apollo 8 was returning home. Jim Lovell was busy with his programme of navigation exercises and as he punched away at the DSKY, its attitude light went out. ‘ For some reason.’’ he called to Mike Collins in mission control, "we suddenly got a Program 01 and no attitude light on our computer.”

Program 01 was only meant to be used at the start of a mission to initialise the IMIJ platform. In effect, the computer had lost its knowledge of which way was up.

‘’Stand by one, Jim.” said Collins. "We’re working on a procedure for getting you cranked back up again.”

"Okay.”

Lovell had meant to enter Program 23. the navigation program, and then use Star 01. A slip of the fingers and a couple of missing keystrokes meant that he had entered Program 01 in error. Unfortunately, there was no Undo button. In view of the huge amount of work Lovell had to perform on this pioneering flight, and his severely disrupted sleep patterns, an occasional slip was to be expected. At least it had occurred when it had no impact on the mission. To recover from the error, he had to realign the platform from the beginning using the stars. Mission control had to uplink a refresh of their REFSMMAT and check other data in memory because of what the computer had forgotten during the reset; all of which took about an hour of their З-day coast home.

Amused, both Borman and Anders constantly ribbed Lovell about his error for the rest of the journey.