Space astronauts

Two US astronauts ventured outside the International Space Station's airlock this morning to work on the maintenance of the station.

The astronauts were outside the space station for six and a half hours

Their tasks included installing a thermal cover on the state-of-the-art particle physics detector that has been attached to the station since 2011.

The spacewalk was the 32nd carried out by US astronauts and the first for both astronauts, who were also assisted from inside the station by Japanese astronaut Kimiya Yui.

Monitoring the activities from the ground at Nasa HQ was Tracy Caldwell, who has worked on three spacewalks.

Scott Kelly (l) and Kjell Lindgren (r) who have never spacewalked before

In preparing for their walk, the astronauts have been assisted by veteran Russian cosmonauts from the other side of the space station who helped them understand how the immune system is affected by stress in space.