NASA no longer plans to conduct the first all-female spacewalk this week, citing issues with spacesuit sizing. Originally, NASA astronauts Christina Koch and Anne McClain were scheduled to swap out batteries on the outside of the International Space Station this Friday in what would have been a historic event. But now, NASA has decided that astronaut Nick Hague will take McClain’s place.

The space agency says the issue has to do with the types of space suits that are available on the ISS. After completing a successful spacewalk with Hague on Friday, March 22nd, McClain realized that she is best suited to wearing a suit with a “medium-size hard upper torso” instead of a large-sized one. NASA has at least two medium-sized spacesuit torsos on the ISS, according to a NASA spokesperson, but only one of them will be ready for the upcoming spacewalk on Friday. NASA decided that Koch and Hague will wear the suits that are already prepared, rather than reconfigure the spacesuits before Friday. Changing the suit would require adding arm and leg segments to the medium-sized torso, which can be a fairly labor-intensive process.

Before the swap, Friday’s spacewalk was set to be led by women both in space and on the ground. Kristen Facciol of the Canadian Space Agency announced that she would be on console for the excursion, while Mary Lawrence and Jackie Kagey would serve as lead flight controller and lead spacewalk flight controller, respectively.

For now, it does not seem that NASA will try to do another women-only spacewalk in the near future. ISS astronauts are set to do three spacewalks total in March and April to swap out aging nickel-hydrogen batteries with new lithium-ion ones. After the spacewalk this upcoming Friday, McClain will most likely perform the third spacewalk with Canadian astronaut David Saint-Jacques on April 8th, in order to lay out jumper cables. However, NASA says it has not finalized the assignments for that spacewalk, so things could still change.

It’s unclear when a spacewalk with only women will occur. The first woman to ever perform a spacewalk was cosmonaut Svetlana Savitskaya, who worked outside the Soviet space station Salyut 7 in 1984. Only 12 additional women have spacewalked since, and Koch will become the 14th female spacewalker on Friday. Since 1998, 214 spacewalks have occurred at the International Space Station, according to NASA.

Update March 25th, 10PM ET: This article was updated to clarify new comments from a NASA spokesperson.