The world's first spacewalker, Russian cosmonaut Alexei Leonov, has died at the age of 85.
"His early exploits in space set the stage for later accomplishments by both the Soviet Union and the United States".
Russian space fans were bringing flowers to his monument Friday on the memorial alley in honour of Russia's cosmonauts in Moscow.
Leonov helped train other cosmonauts before retiring in 1992, a year after the Soviet Union collapsed. He was a friend of Yuri Gagarin, who became the first man in space in 1961 and trained with him.
Nasa on Friday offered its sympathies to Leonov's family, saying it was saddened by his death.
The first American to walk in space, Ed White, wouldn't do so until June that same year.
Leonov recounted the attractive and harrowing experience of his spacewalk mission in the book Two Sides of the Moon, co-written with NASA Apollo astronaut David Scott.
The documentary film "The Man Walking In Space" followed Leonov on his famous orbit.
Koch, who is seven months into her space flight, will set out on the first ever female spacewalk on Monday, October 21 after the first attempt was called-off due to spacesuit issues.
Tributes have poured in for Alexei Leonov.
Russian cosmonaut Oleg Kononenko said Leonov's death was a "loss for the whole planet", while President Vladimir Putin said he admired the astronaut's courage.
Leonov was also selected as the first Soviet to land on the Moon, but he never got the chance after the mission was scrapped.
The cosmonaut was well known for his humour.
Leonov was an accomplished artist and writer and his contemporaries described him as warm and likable. He's survived by his wife, Svetlana, who worked for Russia's Cosmonaut Training Center; their daughter, Oksana; and two grandchildren.
He helped many cosmonauts and was a "great storyteller", space historian Alexander Glushko said.
Roscosmos said Mr Leonov's funeral will take place on Tuesday at a military cemetery outside Moscow.