Russian cosmonaut Sergei Krikalev became the man staying the longest in space Tuesday after clocking 748 days.

Krikalev, one of the two crewmembers currently working on International Space Station (ISS), beat the previous record set by fellow Russian Sergei Avdeyev, who spent 747 days and 14 hours in space, the Mission Control said.

Krikalev, who has completed missions on both the now-defunct MIR space station and the ISS, beat the record while asleep and woke up a record-holder Tuesday.

On Tuesday, the Russian cosmonaut and his partner US astronaut John Phillips prepared for a spacewalk scheduled for Thursday, the Mission Control said.

Krikalev and Phillips, who have been working on the space station since mid-April, are expected to return to Earth in October after completing their mission.

Editor: Yan