Men have floated out the hatch on all 420 spacewalks conducted over the past half-century.
That changed Friday with spacewalk No. 421.
NASA astronauts Christina Koch and Jessica Meir ventured outside the International Space Station before 8 a.m. ET Friday and will spend over five hours replacing a broken battery charger, or BCDU. NASA's livestream of the historic spacewalk features astronaut Tracy Caldwell Dyson as one of the female narrators.