First All-Woman Spacewalk Scrapped for Lack of Spacesuits in Female-Friendly Sizes

A giant leap for (wo)mankind will have to wait.

Earlier this month, NASA announced that two female astronauts, Anne McClain and Christina Koch, would participate in a history-making first: an all-woman spacewalk at the International Space Station. They were going to be supported by a number of women on the ground and a female flight controller.

But their plans hit a snag: there are not enough spacesuits available in sizes that fit women, so one of the female astronauts is giving up her place to a man. NASA explained in a statement that mission managers “decided to adjust the assignments, due in part to spacesuit availability on the station.”

“McClain learned during her first spacewalk that a medium-size hard upper torso—essentially the shirt of the spacesuit—fits her best,” explained NASA. “Because only one medium-size torso can be made ready by Friday, March 29, Koch will wear it.”

Initially, McClain thought she could use a large-size suit, but after last week’s spacewalk she learned the medium fit better, NASA spokeswoman Stephanie Schierholz told Fortune in a written statement.

She added there are two medium-size hard upper torsos available on the space station, but only one is currently configured for use—the other is a spare. “Given the very busy operational schedule on board the station this spring…the teams made the decision to keep the schedule by swapping spacewalkers rather than reconfiguring a spacesuit,” she added.

Schierholz further explained to The New York Times that “when you have the option of just switching the people, the mission becomes more important than a cool milestone.” Nevertheless, she assured Fortune that “an all-female spacewalk is inevitable” due in no small part to the growing number of female astronauts: 50% of the 2013 astronaut candidate class (of which McClain and Koch are a part) are women.

Now Koch will join NASA astronaut Nick Hague for the spacewalk scheduled on Friday, March 29, while McClain is tentatively scheduled to join Canadian Space Agency astronaut David Saint-Jacques for the third spacewalk in the series on Monday, April 8.

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