NASA initially planned the spacewalk for Thursday, October 17.
The space agency has, however, pushed the event back by one day to Friday, October 18.
The spacewalk is scheduled to kick off at 12.50pm BST (7.50am EDT).
NASA said: “On Friday, October 18, starting at around 5.50am EDT, NASA astronauts Christina Koch and Jessica Meir will venture outside the International Space Station for a spacewalk.
“The duo will exit the station’s Quest airlock in their US spacesuits to replace a power controller that failed over the weekend.”