Two astronauts will venture outside the International Space Station this morning to replace a failed solar-power unit.

The six-and-a-half-hour "extra-vehicular activity" will mark a historic moment for the U.K.'s space program, as Tim Peake becomes the first British astronaut to complete a spacewalk.

(Michael Foale became the first Briton to carry out a spacewalk in 2005 but he did so as a NASA astronaut.)

Peake — along with NASA astronaut Tim Kopra — will also lay cables for new docking ports and retrieve a broken light from a truss camera.

Watch the spacewalk live at 7:55 a.m. ET.