Dressing for launch: foreground to rear, Lovell, Swigert and Haise leaving transfer van.
Even before launch, Apollo 13 provided a sobering reminder that the problems and dangers of exploring space are beyond anticipation and that engineering genius is not without limitations. Sometimes the problems are minor in the context of Earth-bound activities but major for space flight. One such problem occurred during the launch preparations.
The Apollo 13 prime crew was exposed to rubella, or German measles, while working with Charles M. Duke, Jr., of the backup crew, who developed rubella the weekend before the scheduled launch. Examination of the prime crew revealed that Thomas K. Mattingly II, Command Module Pilot, had no immunity to rubella.
A sick astronaut in space could endanger himself and the mission. As a result, doctors ruled out Mattingly for the Apollo 13 flight.
Plans call for use of the entire backup crew when a member of the prime crew is incapacitated. However, Duke's illness ruled that out. Consecjuently, a decision was made to substitute backup Command Module Pilot John L. Swigert, Jr., for Mattingly. Swigert was found to be immune to rubella.
The last-minute change presented difficulties because each trio is trained as a team. In a crisis, each man has learned to rely on his companions' reactions. To work Swigert in, the crew engaged in a vigorous and intensive program simulating all flight maneuvers and ensuring unquestioned teamwork.
At 2:13 p.m. EST, Saturday, April 11, 1970, Apollo 13 and its team (James A. Lovell, Commander; Fred W. Haise, Jr., Lunar Module Pilot; and John L. Swigert, Command Module Pilot) were launched from Kennedy Space Center, Florida. A premature cut-off of one engine of the second stage of their Saturn V launch vehicle Was compensated for by longer burns of the remaining engines and the engine of the third stage. Apollo 13 achieved Earth orbit at 2:26 p.m. EST.