(CNN) The second spacewalk in history to be conducted entirely by female astronauts got underway at the International Space Station early Wednesday morning and concluded seven and a half hours later.

NASA astronauts Jessica Meir and Christina Koch ventured out of the space station shortly before 7 a.m. Eastern Time for the first spacewalk of 2020 and ended at 2:04 p.m. ET. Their mission was to replace batteries on solar arrays on the outside of the ISS. They accomplished those tasks, as well as a get-ahead task.

They are the same astronauts who made history after successfully completing the very first all-female spacewalk in October. That came months after a planned spacewalk with an all-women crew had to be canceled in March because of a lack of suitable spacesuits.

At the end of the spacewalk, Meir congratulated the newest class of astronauts who graduated last Friday. "We are so excited to witness your contributions to human spaceflight," she said.

About a half hour into the spacewalk, Koch's helmet video camera system and lights came loose and the astronauts tried to reattach it to grooves on the helmet. Mission Control then advised them to stow it rather than waste time. At one point, the astronauts asked if the spacewalk would continue, given the lack of lighting for Koch.

.@Astro_Jessica and mission controllers on the ground assist @Astro_Christina with a loose helmet camera on her spacesuit that was eventually stowed in a crew lock bag. #AskNASA | https://t.co/yuOTrYN8CV pic.twitter.com/hvRihbzrSE — Intl. Space Station (@Space_Station) January 15, 2020

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