A Soyuz craft adorned with a portrait of the first man in space docked with the International Space Station on Thursday, days before the 50th anniversary of Yuri Gagarin's pioneering flight.
U.S. astronaut Ron Garan and Russian cosmonauts Alexander Samokutyayev and Andrey Borisenko were to join three crew already aboard the orbital station after the docking, which NASA said took place at 3.09 a.m. Moscow time (2309 GMT Wednesday).
Their Soyuz TMA-21, with a picture of Mr. Gagarin on the side, blasted off hours before dawn on Tuesday from Russia's long-secret Baikonur launch pad in Kazakhstan, where the iconic cosmonaut's April 12, 1961 flight began.
The cramped Soyuz does not look very different from the Soviet craft that took Mr. Gagarin around Earth on a trailblazing 108-minute, single-orbit flight that stunned the world and raised the stakes in the U.S.-Soviet space race.
It was "a giant leap in our evolution as a species", Mr. Garan said in his last blog post before lift off.
Mr. Garan, who grew up believing he was related to the Soviet space idol via a great grandfather who emigrated to the United States under the name Ivan Gagarin, said Gagarin's voyage set the stage for co-operation between nuclear-armed superpowers.
"There is no doubt in my mind that the world is a safer and more peaceful place today than it would be otherwise if we had not taken that first step into space," Mr. Garan blogged.
"Even at the height of the Cold War, Russia and the U.S. still somehow found a way to co-operate during the Apollo-Soyuz program, which accomplished the first docking of US and Russian spacecraft" in 1975.
Very early in life, Soyuz TMA-21 commander Samokutyayev also felt the draw of Mr. Gagarin's heroic flight, a mission that propelled space exploration from the pages of fantasy novels to reality.
Schoolmates jokingly called him "Sasha Gagarin" because he was always playing with a toy rocket, he said.
The superstitious, tradition-steeped cosmonaut corps, and now the Americans flying on the Soyuz, have retraced Mr. Gagarin's steps at every launch, crying: "Poyekhali! - Let's go!"
Each crew also stops the bus shuttling them toward the launch pad to step out and solemnly urinate on the right rear bus tire.
Russian Prime Minister Vladimir Putin, who was two years old at the time of the historic flight, will visit Gagarin's hometown some 150 km west of Moscow on Thursday ahead of the April 12 anniversary.
Moscow is also expecting to welcome the heads of all the world's space agencies for celebrations on Tuesday and talks on the future of human space flight after the space station is retired, due in 2020.