In a commentary track, Marilyn Lovell comments that Tom Hanks exactly portrays Jim Lovell's mannerisms and style of movement.
In some scenes where the Earth can be seen from the windows of Apollo 13, it is one of the photos taken by Jim Lovell and Bill Anders on the Apollo 8 mission.
(at around 2h 10 mins) Jim Lovell wore his old Navy Captain's uniform in the scene where he greets the astronauts aboard the U.S.S. Iwo Jima. When Ron Howard asked Lovell if he'd like to be in the film as the ship's Admiral, Lovell agreed, but pointed out, "I retired as a Captain; a Captain I will be."
Bill Paxton, Tom Hanks and Kevin Bacon were all very proud of the fact that they weren't sick on the so-called Vomit Comet - the plane used to simulate zero gravity. The cameramen weren't so lucky.
The film portrays Jack Swigert as a little wet behind the ears, and potentially incapable of docking the command module with the LEM. However, Jim Lovell has said in an interview that the real Swigert actually wrote the Malfunction Procedures for NASA command modules, and therefore knew the machine incredibly well and was more than capable of piloting the mission. Additionally, Lovell said that, had Swigert not been able to dock the ship, it wouldn't have meant doom for the mission, as there were two other accomplished pilots in the CM who could make another attempt at docking.
Bryce Dallas Howard: (at around 27 mins) director Ron Howard's 13-year old daughter plays the girl in a yellow dress.