MIAMI: French astronaut Thomas Pesquet stepped out on his first spacewalk Friday, on a mission to help upgrade the power system outside the International Space Station with new, refrigerator-sized lithium-ion batteries.

Accompanied by American astronaut Shane Kimbrough, the men switched on their spacesuits´ internal battery power to mark the official start of the spacewalk at 6:22 am (1122 GMT), more than a half hour earlier than scheduled.