Astronauts who flew into space with John Young, and others who followed him into space, paid tribute to their late friend and colleague, who was the ninth person to walk on the moon and led the first space shuttle mission.
Young died on Friday (Jan. 5) following complications from pneumonia. He was 87.
"I am overwhelmed by the news," Charlie Duke, who with Young landed on the moon in 1972, wrote on Facebook on Saturday (Jan. 6). "I've lost a dear friend, my mentor and a dynamic leader." [John Young in Photos: Astronaut, Moonwalker and Space Shuttle Pioneer]
"What a privilege and honor to have known and flown to the moon with my hero," Duke wrote.
Young was NASA's most experienced astronaut, serving for an unmatched 42 years with the space agency. He flew two Gemini missions, launched twice on Apollo missions to the moon and commanded two space shuttle missions.
He also served as the chief of NASA's astronaut office for 13 years and was a presence at Johnson Space Center in Houston as a champion for safety up until and through his retirement in 2004.
"He is going to be remembered by history for all the things that he did, not only the six flights he made, but also his continued oversight of flying in space and as a proponent for space [exploration]," Bob Crippen, who flew with Young on STS-1, the maiden flight of the space shuttle in 1981, told collectSPACE.com on Monday (Jan. 8). "Even after his last flight, John was always there, looking over management's shoulders."
"It would be hard to overstate the impact that John Young had on human spaceflight," wrote Ellen Ochoa, director of Johnson Space Center and a former shuttle astronaut, on Twitter. "Beyond his well-known and groundbreaking six missions through three programs, he worked tirelessly for decades to understand and mitigate the risks that NASA astronauts face."
"He had our backs," Ochoa said.
More than 30 astronauts from NASA and around the world took to social media to share their memories and tributes. Terry Virts, who spent 200 days on the International Space Station in 2015, was the first to note online that Young had died.
"You were one of my heroes as an astronaut and explorer and your passion for space will be missed," Virts wrote on Twitter Saturday morning.
"John Young's unique sense of humor and disarming, Floridian approach to a discussion of complex engineering or operational issues disguised a remarkably insightful, imaginative and innovative mind," wrote Harrison Schmitt, who first worked with Young in support of Apollo 10, prior to following him to the moon on the final lunar landing (to date) on Apollo 17. "John Young, an extraordinary pilot, dedicated engineer and space explorer, will be missed as Americans return to the moon and beyond."
"I will never forget the precious moments learning from a legend in the shuttle mission simulator and T-38 aircraft," wrote Japanese astronaut Koichi Wakata. "Rest peacefully John."
"A pioneer of the U.S. space program and a dear friend from my days in Houston," wrote astronaut Marc Garneau, the first Canadian in space and Canada's current Minister of Transport.
"I never met him, but for those of us that try to follow his path (fighter pilot, test pilot, astronaut) he was more than a model, he was a legend," wrote Luca Parmitano, an Italian astronaut with the European Space Agency (ESA).
"I remember clearly the day that he called me when I was selected [as an astronaut], and the T-38 flights we shared," wrote Timothy "TJ" Creamer, the first astronaut to serve as a flight director in NASA's mission control.
"I will never forget what it was like to have a personal conversation with a legend who walked on the moon. Rest peacefully John Young... you have left behind an indelible mark equalled only by a few," wrote Chris Ferguson, the commander of the final space shuttle mission, STS-135, in 2011.
Young launched on his final spaceflight in November 1983 as the commander of STS-9. Seated to his right as pilot on board space shuttle Columbia was Brewster Shaw.
"A lot of people have already talked about John and John's legacy," said Shaw in a call with collectSPACE on Monday (Jan. 8). "But I don't think people know John as a man or a human being probably as well and that's what means more to me than the fact John's timing was incredibly fortunate that allowed him to do everything that he was able to do."
"John was the kind of guy that every time he walked in the door, you knew what to expect. You knew what you were going to get in regards to what kind of human being you were going to deal with. He was very steady, and he was constant as a human being," Shaw said.
"When we were training together and I would make these huge bonehead mistakes in the simulator, John never got upset. He calmly said, 'Well, what do you think about what just happened? How could we have handled that better? Or what could we have done differently?'" Shaw described. "He would just talk to you through the scenario and the important things to pay attention to."
"John was just such an incredible, intuitive engineer," said Shaw. "He just had a sense of what was going on and what to do about it. So working with him and being trained by him was just an almost indescribable pleasure because he was such a great guy."
"That is what I would like people to know about John," he said, "what kind of human being he was. Not that he was a great American hero, but that he was a great American.”
Read more astronauts' remembrances of the late John Young at collectSPACE.