Christina Koch and Jessica Meir to make history after delay over suit sizes available at station

Nasa is planning the first ever all-female spacewalk as early as Thursday, the space agency has announced.

The walk, or float, will be conducted from the International Space Station by the astronauts Christina Koch and Jessica Meir, who have been living in space since March and September respectively. The news was communicated by the Nasa administrator Jim Bridenstine, via Twitter.

The women’s mission is to replace a faulty battery charging unit on the outside of the station, which failed last weekend, Nasa said.

Astronauts and cosmonauts have completed more than 200 spacewalks during the construction and maintenance of the International Space Station, but only 15 women have ever been on a spacewalk, always accompanied by men. There hasn’t been an all-female event in more than a half-century of space walking.

The walk was originally scheduled to take place more than six months ago, involving Koch and the Nasa astronaut Anne McClain, but the exercise had to be delayed because Nasa did not have enough of the correctly sized suits available and ready to use on the station. There was only one useable medium-sized suit available in time, and the women needed one each.

McClain came back to Earth in June and Nasa has since blasted a second medium spacesuit up to the station, so that the walk – which could take place on Thursday or Friday – could happen.

“It turns out that over the next couple of years we’re having a lot of medium-suit people fly, and so that’s the sweet spot,” the program manager for the International Space Station, Kirk Shireman, told a press briefing earlier this month.

Separately, the agency has unveiled prototypes of its next-generation spacesuits to be worn inside the Orion spacecraft and on the surface of the moon, because American astronauts are scheduled to return there as early as 2024.

One is designed for walking on the moon. The other is a bright orange pressure suit to be worn when astronauts launch from Earth and return.

Nasa recently demonstrated that the new suits will allow astronauts to bend, squat and lift their arms above their heads – a facility space suits have restricted until now.

“This is the first suit we’ve designed in about 40 years,” Chris Hansen, a manager at Nasa’s spacesuit design office, said. “We want systems that allow our astronauts to be scientists on the surface of the Moon.”

Amy Ross, Nasa’s lead spacesuit engineer, said: “Basically, my job is to take a basketball, shape it like a human, keep them alive in a harsh environment and give them the mobility to do their job.”

The new lunar suit should also help overcome Nasa’s spacesuit sizing issues: it is a one-size-fits-all garment designed for both men and women.

Six people are serving on the space station’s current mission: Koch, Meir, fellow Nasa astronaut Andrew Morgan; Russian cosmonauts Aleksandr Skvortsov and Oleg Skripochka; and the European Space Agency’s Luca Parmitano.