One of the most complex ever construction missions at the International Space Station got underway on Thursday with a spacewalk to attach a $790 million truss.

The 13.5-metre, 13-tonne “S-Zero” truss was lifted out of shuttle Atlantis using the ISS’s robot arm, Canadarm2. It was temporarily attached to the top of the station’s Destiny science module at 1347 GMT.

Eight more sections will be added to the S-Zero truss to complete the 109-metre frame, during future shuttle missions. The full frame is designed to hold a 100-metre solar array, which will be used to provide power for the existing laboratories on board the station as well as future scientific modules.