May 12, 2017 7:57 AM EDT

Two NASA astronauts are set to complete the 200th spacewalk outside the International Space Station Friday.

For Jack Fischer, the Verge reports, it will be his first ever spacewalk. But Peggy Whitson is a pro. She holds the record for most spacewalks by a female U.S. astronaut (today will be her ninth), and she’s spent more days off the planet than any other woman (more than 500 days total). President Donald Trump called her last month to congratulate her on the milestone.

On Friday’s walk, Fischer and Whitson will make some necessary repairs to the space station. The space walk starts at 8 a.m. EST and is expected to continue for more than six hours.

Write to Tessa Berenson at tessa.berenson@time.com.

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