Veteran Fyodor Yurchikhin and first-timer Jack Fischer set off in bright conditions at 8.13am United Kingdom time.
A rare two-man crew is scheduled to blastoff aboard the Soyuz MS-04 spaceship and travel to the International Space Station. They reached orbit about nine minutes later, a moment illustrated when a small white stuffed dog hanging from a string in the capsule began to float.
Two Expedition 51 crew members are in quarantine today at the Cosmonaut Hotel in Baikonur, Kazakhstan, getting ready for their liftoff Thursday morning. "You just can't train for that on the ground, so I approach my space-toilet activities with respect, preparation and a healthy dose of sheer terror".
But Russian space agency Roscosmos announced a year ago that only two cosmonauts would travel to the ISS this time as it cuts costs before the installation of a new module to expand the Russian section of the orbital lab at the end of 2017 or in early 2018.Another Russian-American duo, Yuri Malenchenko and Edward Lu, undertook the last two-man mission to the ISS, in April 2003.
The 43-year-old might want to seek some advice from fellow NASA astronaut Peggy Whitson, who is going to receive an out-of-this-world call from President Donald Trump on Monday after beating a special record.
In this April 13, 2017, image from video made available by NASA, astronaut Peggy Whitson speaks during an interview aboard the International Space Station.
France's Thomas Pesquet and Oleg Novitsky of Roscosmos will be the next members of the ISS crew to return to Earth, with a landing scheduled for early June.