NASA Astronauts Perform First-Ever All-Women Spacewalk: 'History Is Being Made'

Two women ventured outside the International Space Station to fix a faulty power controller early Friday morning in what was the first-ever all-female spacewalk.

Christina Koch and Jessica Meir’s mission was live-streamed by NASA starting at 7:38 a.m., and the astronauts’ replacement of the battery charge/discharge unit was expected to take about five and a half hours.

In the livestream, Koch (wearing a spacesuit with red stripes) ⁠and Meir (wearing a suit with no stripes) can be heard talking to each other and astronaut Stephanie Wilson from Mission Control.

The unit Koch, 40, and Meir, 42, are replacing failed to activate after the Oct. 11 installation of new lithium-ion batteries on the space station’s exterior structure, but hasn’t affected operations or the safety of the crew, NASA said in a press release.

According to NASA, their spacewalk ⁠— the name for any time an astronaut gets out of a vehicle while in space ⁠— is the 221st in support of station assembly, maintenance and upgrades, and the eighth outside the station this year.

It’s just the 43rd to include a woman after Russian cosmonaut Svetlana Savitskaya became the first in 1984. U.S. astronaut Kathryn Sullivan followed in her footsteps several months later.

Both Koch and Meir were selected as part of NASA’s 2013 astronaut class; this is Koch’s fourth spacewalk and Meir’s first. Koch is also on track to set the record for longest single spaceflight by a woman, with an expected total of 328 days in space, according to her NASA biography.

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A spacewalk featuring Koch and astronaut Anne McClain was slated to happen in March, but the history-making moment was postponed because the women both needed medium-sized spacesuits, and NASA did not have enough available. Koch went on to perform the spacewalk with astronaut Nick Hague.

Koch and Meir’s spacewalk was then scheduled for Oct. 21, but was bumped up after the failure of the power controller, which the New York Times reported had been in operation for 19 years.

The women’s journey was celebrated on Twitter by famous figures like Speaker of the House Nancy Pelosi and Billie Jean King, who commended their place in history.

“History is being made right this second. Tune in to watch the #AllWomanSpacewalk! Congratulations to @Astro_Christina and @Astro_Jessica! #trailblazers,” King wrote.

Added Pelosi, “@NASA has captured the imaginations of the world for generations. Congratulations to @Astro_Christina & @Astro_Jessica for leaving their mark on history with today’s #AllWomanSpacewalk. You are an inspiration to women & girls across America.”