The International Space Station's two women are prepping for the first all-female spacewalk.

U.S. astronauts Christina Koch (cook) and Jessica Meir (mere) will step out Friday to replace a broken battery charger. It will be the first time in 54 years of spacewalking that all the male astronauts stay inside.

The battery charger failed after Koch and a male crewmate installed new batteries outside the station last week. NASA put the remaining battery replacements on hold to fix the problem and moved up the women's planned spacewalk by three days.

NASA is asking schoolteachers to share photos of their students celebrating "HERstory in the making."