He had the Measles.
Ken Mattingly was replaced as the command module pilot for Apollo 13 because he was exposed to German measles and had no immunity to it. To ensure the safety of the crew, Mattingly was replaced by Jack Swigert.
James Lovell of Apollo 13, was never replaced instead it was Ken Mattingly who was replaced by Jack Swigert.
He had the measles but later found out he didn't.
The astronaut who did not fly on Apollo 13 was Ken Mattingly. He was originally part of the Apollo 13 crew but was replaced by Jack Swigert after being exposed to German measles.
Ken Mattingly flew as Command Module Pilot on Apollo 16.
It was Astronaut Jack Swigert who replaced the sick astronaut Thomas Mattingly.
The original three crew members of Apollo 13 were James Lovell, Fred .w.Haise and Thomas K. Mattingly. But Mattingly was grounded as he got measles . Jack Swigert replaced him.
Well, The crew that was supposed to go on Apollo 13 was Alan Sheppard's crew, but he got an ongoing ear infection so he and his crew got bumped. Afterwards, Jim Lovell and his crew (Fred Haise, and Ken Mattingly) were assigned for the Apollo 13 mission, but because the doctors thought Ken Mattingly was going to have the measles, he got bumped from the mission and was replaced with Jack Swigert. Hope this helps! :)
Jack Swigert replaced Ken Mattingly on the Apollo 13 mission due to Mattingly's exposure to German measles shortly before the flight. NASA decided to ensure the health and safety of the crew, as Mattingly could have been contagious. Swigert, who was already a backup astronaut, stepped in at the last minute to fill Mattingly's role as the command module pilot.
Ken Mattingly was originally assigned to the Apollo 13 mission but was replaced by Jack Swigert due to concerns of exposure to German measles.
The original crew for Apollo 13 included Jim Lovell, Fred Haise, and Ken Mattingly. However, Ken Mattingly was replaced by Jack Swigert just days before the mission due to concerns about his exposure to German measles.
He played Gary Sinise, but don't remember how big a part that was.