The historic mission scheduled for March 29 has had to be abandoned because NASA won’t be able to produce the correctly sized outerwear in time.

The original plan: Christina Koch and Anne McClain were due to make history by carrying out the first ever all-female spacewalk. Their task was to walk outside the International Space Station to install new batteries.

Back to the drawing board: NASA said the change of plan was “in part due to spacesuit availability on the station.” Specifically, during McClain’s spacewalk with her colleague Nick Hague on March 22, she learned that a medium-size hard upper torso—basically the “shirt” of the suit—fits her best. Because only one spacesuit of that size can be made ready by Friday, Koch will take the next turn and wear it. It’s worth noting that spacesuits are unisex, so this wasn’t a case of NASA failing to make enough “women’s” suits.

A little bit of history: Last Friday, McCain became the 13th woman to perform a spacewalk, while Koch will become the 14th this upcoming Friday, March 29. To announce and then cancel the first all-female spacewalk is a huge letdown, but it’s surely only a matter of time until NASA gets the next one scheduled.

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