French astronaut Thomas Pesquet and NASA's Shane Kimbrough made their second spacewalk in less than a week to install new solar panels on the International Space Station.
The pair were continuing a project they started on Wednesday, which ground to a halt after spacesuit and other issues stopped them from unrolling the first in a series of high-tech solar panels.
NASA originally planned two spacewalks for the job; one for each solar panel. But managers have scheduled a third because of the earlier problems.
The new solar wings are designed to roll out like a red carpet, unlike the station's old ones which unfolded like an accordion.
Pesquet and Kimbrough managed to bolt down the first solar wing last week, but had to delay making the electrical connections or unfurling the panel to its full 19-metre length.
On Sunday, pushing and tugging, the spacewalkers managed to unfold and align the solar panel so both halves were end to end, resembling a roll of paper towels. Their shout of “Woo-hoo!" was met with applause in Mission Control.
The two had to wait until they were back on the night side of Earth so that the station's old solar panels were no longer soaking up sunlight, or they could have been shocked.
While awaiting darkness the camera-and-light assembly on Kimbrough's helmet had come loose, and was secured by Pesquet with wire ties as the minutes ticked by. This time, the final step — the actual unfurling — went off without a hitch.
The slow but steady extension on Sunday took 10 minutes in total, with station cameras providing live TV views. “It is beautiful,” Pesquet called out.
The pair will go back out Friday to complete work on the second panel, which was delivered by private firm SpaceX earlier this month.