Astronauts Christina Koch and Jessica Meir are scheduled to complete NASA's first all-female spacewalk this week. 

The walk was originally scheduled for Monday, but will now take place on Oct. 17 or Oct. 18 to replace a power controller that failed during the weekend. NASA officials announced the change today. 

"@Space_Station update: our first all-female spacewalk with @Astro_Christina and @Astro_Jessica will be Thursday or Friday to replace a faulty battery charge-discharge unit," NASA chief Jim Bridenstine wrote on Twitter. More information will be shared in a press conference later today, according to Bridenstine. 

.@Space_Station update: our first all-female spacewalk with@Astro_Christina and@Astro_Jessica will be Thursday or Friday to replace a faulty battery charge-discharge unit. We’ll have a telecon later today. More details:https://t.co/0T6OOfuQQcpic.twitter.com/zQ7cH4fIBg

— Jim Bridenstine (@JimBridenstine)October 15, 2019

The first all-female spacewalk was originally supposed to take place in March with Koch and NASA astronaut Anne McClain, but it had to be postponed when properly fitting spacesuits weren't ready in time.

According to Space.com, only 15 women have completed a spacewalk. All were accompanied by men.