MOSCOW -- Aleksei Leonov, the Russian cosmonaut who was the first human to walk in space, has died at the age of 85 after a lengthy illness.
The press service of the Yuri Gagarin Cosmonaut Training Center said Russia's 11th cosmonaut died at 12:40 p.m. at a hospital in Moscow on October 11.
Leonov made history on March 18, 1965, when he stepped out of his Voskhod 2 spacecraft and went for a spacewalk that lasted 12 minutes.
"I could hear my heart beating, my heavy breathing, and nothing else," he once said of his historic adventure.
The short foray, a significant advance in the space race between the Soviet Union and the United States, was no easy task, and not without its mishaps.
Tethered to the spacecraft, Leonov floated around, pulling himself back to the ship in short intervals.
While it looked to be floating effortlessly, his mission nearly ended in tragedy when his suit inflated because of the lack of atmospheric pressure in space, making it impossible for him to get back on board.
Unknown to mission control back home, he took the dangerous step of using a valve to release oxygen from his suit, a risky move since it could starve him of air he needed to survive.
But the move worked and though he was suffering from the effects of a rapid change in pressure, he managed to get back onto the ship, though only by doing it backwards to make sure he fit.
President Vladimir Putin "always admired Leonov's courage and believed he was a man among men, with a capital M," Kremlin spokesman Dmitry Peskov told the TASS news agency, adding that Putin was deeply aggrieved by Leonov's death.
Leonov was also selected as the first Soviet to land on the Moon, but he never got the chance after the mission was scrapped.
Still, he went on to lead the Soviet half of the Soyuz-Apollo mission, which a decade later became the first joint space mission with the United States.
"A big, likeable character from the heroic era of space exploration," said Roger Highfield, a visiting professor at Oxford University's Dunn School of Pathology and a writer who had interviewed Leonov.
Leonov was also known as an author and painter, with some of his works used on Soviet postage stamps.
A major general in the Soviet Air Force, he retired from service in 1992.