Just before the mission began things started to go wrong. The weekend before launch Charlie Duke, the backup lunar module pilot, came down with a case of German measles.

Aside from physically training for the longest crewed missions that the United States had ever attempted, the actual training program was developed simultaneously with the hardware and experiments for the mission.

The backup crew and some support crew participated in an interesting rescue scenario with 2 astronauts flying to Skylab to take back the crew of 3 onboard Skylab. This would mean 5 astronauts returning to earth in the command module.

“Near the end of our preparation period, management said; Well, we believe, we can do this, now let’s set about to see how we can get them down without expending the resources for a rescue mission.  So just overnight we changed goals.” Vance Brand