Russian cosmonauts Gennady Padalka and Yury Malenchenko started on Monday a six-hour spacewalk to carry out a number of maintenance tasks on the International Space Station (ISS), the Mission Control said.

The spacewalk was delayed for about 40 minutes due to some minor problems with transition hatches between the Pirs docking module and the Zvezda module.

The cosmonauts will perform several maintenance tasks, launch a microsatellite and collect a number of bio specimens from the surface of a docking module to later send them to Earth for study.

It is the second spacewalk performed by Russian members of the ISS crew this year. Anton Shkaplerov and Oleg Kononenko carried out a spacewalk in February to move a 14-meter crane from a docking module to a small scientific module (MIM-2) and to install additional shields to protect the ISS from space debris.

Both Padalka and Malenchenko are veteran cosmonauts with a lot of experience venturing outside the orbital station. It is the ninth spacewalk for Padalka and the fifth for Malenchenko in their space careers.