NASA confirmed plans for the first all-female spacewalk in history was thrown out due to sizing issues of a second space suit.
Christina Koch and Anne McClain were arranged to step outside the International Space Station (ISS) to install batteries on Friday.
But their need for medium sized suits halted the historic moment as only one was ready for use.
NASA made the decision to change the astronauts due to time and safety constraints over configuring the secondary medium-sized suit.
Male colleague Nick Hague will instead take McClain’s place to exit the ISS.
Koch will wear the only medium spacesuit which was first used by McClain on her walk with Hague last week.
McClain trained in both medium and large-sized spacesuits but only discovered on her actual spacewalk that the medium-size suit fitted her best, Nasa said.
The Astronaut is scheduled for her next spacewalk, on 8 April with David Saint-Jacques.