Apollo astronaut Thomas K. dies Mattingly, one of the country’s “heroes.”

(CNN) — Apollo astronaut Thomas K. died. Mattingly II died at the age of 87.

“On October 31, we lost one of our country’s heroes,” NASA Administrator Bill Nelson said in a statement. “NASA astronaut T. K. Mattingly was essential to the success of the Apollo program, and his remarkable character will ensure that he is remembered throughout history.”

Mattingly, who began his career in the U.S. Marine Corps, ended up entering the Air Force’s Aerospace Research Experimental School as a cadet, before being selected by NASA to be part of its astronaut class in 1966, according to the release.

Mattingly’s career is distinguished by his contributions to the Apollo program.

“Perhaps his most dramatic role at NASA was after he was exposed to rubella just before the Apollo 13 launch,” Nelson said. “He made key real-time decisions to successfully bring home the injured spacecraft and Apollo 13 crew: NASA astronauts James Lovell, Jack Swigert, and Fred Haise.”

Actor Gary Sinise played Mattingly in the movie Apollo 13.

Earlier this year, Sinise called it an “honor” to play Mattingly in an X post marking the anniversary of the Apollo 13 mission.

In addition to his role on that mission, Mattingly also participated in Apollo 16, where “his unparalleled skill as a pilot assisted us as he assumed the role of command module pilot for Apollo 16 and spacecraft commander on the STS-4 missions.” “STS 51-C for the Space Shuttle,” Nelson said. “Commitment to innovation and resilience in the face of opposition make TK an excellent person to embody our mission and impress our nation.”

Nelson said Mattingly’s contributions “enabled advances in our learning outside of space.”

He described his experience in orbit by saying: “I had a very distinct fear that if I saw too much, I wouldn’t be able to remember it. “It was very impressive.” He saw the vastness of the universe as endless. “Forum of Possibilities,” Nelson said. “As a pioneer of exploration missions, TK will be remembered for challenging the unknown for the future of our country.”