Canada’s most famous astronaut reached royal realms on Thursday (Feb. 9).

King Charles III met with Chris Hadfield, the retired Canadian astronaut best known for commanding the International Space Station (ISS) in 2012-13 with social media flair. The discussion concerned “efforts to encourage sustainability in space,” the official Royal Family Twitter account (opens in new tab) stated. 

“What a pleasure and privilege to be asked to advise and assist, and make the King laugh,” Hadfield wrote of the experience on Twitter (opens in new tab), alongside a picture showing His Majesty looking amused.

Specifics of the conversation have not yet been shared, but “sustainability” could refer to dealing with problems such as space debris, the light pollution affecting our night sky, or overall environmental concerns raised by rocket launches, for example. King Charles III is a noted environmentalist, particularly seeking to address problems like climate change, according to our sister publication Country Life (opens in new tab).

Related: Life in space: Astronaut Chris Hadfield’s video guide

Hadfield was a fighter pilot with experience flying sorties for NORAD (the North American Aerospace Defense Command) before joining the Canadian Space Agency in 1992. He retired from the Canadian Air Force as a colonel in 2003 after 25 years of service.

Hadfield flew three times in space during his 21 years as an astronaut. He was the only Canadian to visit Russia’s Mir space station, doing so in November 1995. He also was the first-ever Canadian to spacewalk, which happened during the installation of the robotic Canadarm2 on the ISS in April 2001. 

Hadfield’s extravehicular crewmate in 2001, NASA’s Scott Parazynski, was named an “honorary Canadian” during one sortie with Hadfield in which the Canadian anthem was played in space (opens in new tab). Incidentally, Hadfield got one more orbital rendition of “O Canada” (opens in new tab) when he assumed command of the space station in 2013.

Chris Hadfield was the first Canadian astronaut to perform a spacewalk, in April 2001. Note …