A Russian Soyuz TA-16M rocket with two Russian cosmonauts and one American astronaut has lifted off from the Baikonur Cosmodrome in Kazakhstan on route to the International Space Station (ISS).
The craft left Earth late on March 27 carrying Gennady Padalka, Mikhail Kornienko, and Scott Kelly to the ISS.
Kornienko and Scott will remain aboard the ISS for about one year, the first time anyone will have remained in space that long in some 20 years.
Kornienko and Scott will be monitored to learn more about the effects on the human body from such a long period in space.
The last time anyone stayed that long in space was aboard Russia's Mir space station in the 1990s.
The trip has special significance for cosmonaut Padalka, the commander of the crew, as he should break the record for the most combined time in space, which currently is 803 days.
Padalka is only staying aboard the ISS for some six months, but when he returns he should have logged 878 days in space.
Based on reporting by TASS and Interfax