The Captain of the Iwo-Jima that Tom Hanks is talking to at the end of the movie is the real Jim Lovell.

The Apollo 13 mission set a record for the greatest distance from Earth ever achieved by mankind. This occurred because unlike the other Apollos, Apollo 13 did not make a burn behind the moon to drop into lunar orbit. The free-return trajectory the mission followed took the spacecraft farther behind the moon than any other mission.

The exchange between Lovell and his wife about holidays ("you know that Easter vacation?  There's been a change of destination ... how about the moon?") in fact took place in 1968, when Lovell was assigned to Apollo 8 and so missed his planned Christmas vacation.

Ron Howard's mother and father have cameos in the film. Ron's father, Rance Howard, plays the priest who keeps a vigil with the family, and his mother, Jean, plays Jim Lovell's mother. Submitted by wizard_of_gore

Ron Howard's wife appears as one of the nuns in the VIP crowd for the launch. Submitted by wizard_of_gore

Thomas K. Mattingly (played by Gary Sinise), is bald (as opposed to Gary's full head of hair), and about 8 inches taller than the actor. Adm. Mattingly also speaks with a Texas accent.

When Bill Paxton vomits they used Beef-a-Roni stew for the vomit. Since they only had to use a spoonful for each take, they had half a can left at the end of the day. After losing a bet with Tom Hanks, Bill had to then eat the rest of the can. Bill Paxton confirmed this personally at an autograph signing.