A much-anticipated first all-female spacewalk scheduled for Friday has been scrapped because the International Space Station is not carrying enough spacesuits in the right size.

Astronauts Anne McClain and Christina Koch were scheduled to do the spacewalk together but those plans have been changed "due in part to spacesuit availability on the station," NASA said in a statement Monday.

The agency said that McClain realized during her first spacewalk with fellow astronaut Nick Hague on March 22 that a medium-sized hard upper torso, which the agency calls "the shirt of the spacesuit," fits her best.

"Because only one medium-size torso can be made ready by Friday, Koch will wear it," NASA said.

Koch will now go out on a spacewalk with Hague on March 29 while McClain is tentatively scheduled to perform her next spacewalk — the third in this series — on April 8 with Canadian astronaut David Saint-Jacques.

Neither Koch nor McClain commented on the change of plans on their Twitter accounts, which astronauts frequently use to post updates from the space station.

The announcement caused a stir on social media with many questioning why NASA does not have enough spacesuits that fit women on the space station.

"Gotta love the irony that because women have never spacewalked together before there aren't enough suits so the spacewalk can't happen," one Twitter user said. "What a joke."

NASA spokeswoman Stephanie Schierholz told NBC News there are two medium-sized hard upper torso components of the spacesuit on the station, but one of them is a spare that would need additional work to be configured for use.

"It is more efficient to swap spacewalkers than to reconfigure the elements of the spacesuit," she said in a written statement, adding that spacesuits are not “one size fits all” and an optimally fitted spacesuit improves an astronaut’s ability to accomplish tasks.

NASA further explained their decision in a tweet Tuesday.

"To clarify, we have more than 1 medium size spacesuit torso aboard, but to stay on schedule with @Space_Station upgrades, it’s safer & faster to change spacewalker assignments than reconfigure spacesuits," the tweet said.

She said McClain trained in both a large suit and a medium suit on the ground, but sizing needs of crew members may change when they are in orbit.

The all-female spacewalk was supposed to feature McClain and Koch in space, aided on the ground by flight directors Mary Lawrence and Kristen Facciol at NASA's Mission Control at the Johnson Space Center in Houston.

No ordinary battery swap & work day routine. Pics from suiting up Anne & Nick for their first spacewalk! 7 hours later, success upgrading the batteries that allow us to have power even when we’re shadowed by the Earth from the sun! Great day of teamwork both on and off the Earth. pic.twitter.com/a3R6y2jC7Q — Christina H Koch (@Astro_Christina) March 25, 2019

Koch and McClain were both chosen from NASA’s 2013 astronaut candidate class, which had the second-highest number of applicants that the space agency has ever received. Of the eight candidates selected in 2013, half were women, representing a mix of scientists and military pilots.

In 1963, Russian cosmonaut Valentina Tereshkova became the first woman to fly in space. NASA astronaut Sally Ride became the first American woman in space when she launched aboard the space shuttle Challenger in 1983 as part of a five-person crew.

According to NASA, McClain became the 13th woman to perform a spacewalk March 22. Koch will become the 14th woman to accomplish the feat March 29. In total, 214 spacewalks have been performed at the space station since December 1998.