MELBOURNE, Fla. (CBSDFW.COM) – There’s one small step being made in outer space this week… but is it a step forward?

Two female astronauts had been scheduled to make history, by stepping outside the International Space Station (ISS) together to install new batteries on a pair of solar arrays. But it turns out NASA doesn’t have enough spacesuits that fit the women.

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Astronauts Christina Koch and Anne McClain had been scheduled to conduct the spacewalk together on Friday.

NASA said they talked with McClain after her first spacewalk in the series, on March 22 with astronaut Nick Hague, and she found that she wasn’t able to maneuver comfortably in her size large spacesuit and that a medium-size fit her best.

NASA said they then decided to adjust the spacewalk assignments, “Because only one medium-size torso can be made ready by Friday, March 29, Koch will wear it.”

NASA has two medium-size hard upper torso spacesuits on the ISS but only one of them has been properly configured for a spacewalk.

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“When you have the option of just switching the people, the mission becomes more important than a cool milestone,” NASA spokeswoman Stephanie Schierholz told the New York Times.

NASA astronaut Christina Koch (center) assists fellow astronauts Nick Hague (left) and Anne McClain in their U.S. spacesuits on March 22, 2019. (credit: NASA)

As part of Expedition 59, the astronauts are scheduled to take three spacewalks to complete work on the ISS. Friday’s mission will be the second. According to NASA it should last about seven hours.

But McClain and Koch will still be making history this month by becoming the 13th and 14th women to perform a spacewalk. McClain is scheduled to perform her next spacewalk on April 8 with Canadian astronaut David Saint-Jacques.

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Both McClain and Koch were part of the 2013 NASA astronaut class, half of which were women.