Astronauts from the Endeavour space shuttle completed the first spacewalk of the STS-127 mission on Saturday. Image: NASA.

Astronauts on the Endeavour space shuttle mission STS-127 have completed the first of five spacewalks outside the International Space Station (ISS).

The Endeavour space shuttle docked at the ISS on Friday after lifting off on Thursday from the Kennedy Space Center in Florida.

Spacewalkers Dave Wolf and Tim Kopra began their six and a half hour excursion outside the ISS on Saturday (18 July).

Their main task was preparing of the Japanese Kibo space laboratory for the installation of the Japanese Exposed Facility (JEF). The JEF will be used in experiments testing materials against the harsh environment of space.

Work also included attaching a 1.9-tonne platform to Kibo’s two pressurised modules.

The spacewalk was ended one hour ahead of its estimated time, only lasting five hours 32 minutes. This was the 126th spacewalk completed at the ISS and time spent on the preparation of space station now totals over 785 hours.

They fell behind schedule during the walk and were unable to complete all planned tasks.

NASA also stated that the communications systems encountered problems during the walk but were not a risk to the astronauts’ safety and will be rectified before the next planned spacewalk later today (20 July).

For more information about the Endeavour STS-127 mission, visit: http://www.nasa.gov/shuttle