Two Russians cosmonauts went on a spacewalk Wednesday to retrieve and replace biological samples from outside the International Space Station.

Cosmonauts Yuri Malenchenko and Sergey Volkov set out to retrieve the samples that had been kept outside of the space station for seven years and put new science trays in their place.

The samples are part of the European Space Agency's Expose-R experiment which tests the effects of radiation, microgravity and extreme temperatures on different organic molecules in the vacuum of space.

British astronaut Tim Peake and American Tim Kopra attempted a spacewalk on Jan. 15, but the mission was cut short after water leaked into Kopra's helmet. The cosmonauts use different suits so a similar problem is not expected to occur.

NASA hosted a livestream of the mission, which began with the cosmonauts releasing a flash drive that contained videos and messages regarding the 70th anniversary of Russia's Victory Day.

During the 5 1/2-hour mission the two were also tasked with testing a new glue for use on the station's exterior and installing gap spanners to allow easier movement for crew members on future spacewalks.