U.S. astronauts Jessica Meir and Christina Koch make the first all-female spacewalk outside the International Space Station in a still image from video October 18, 2019. NASA/Handout via REUTERS.

Trailing lights from stars in space and from sources on Earth are seen in this composite time-lapse image taken during orbit over Namibia to the Red Sea aboard the International Space Station, July 5, 2019. Image obtained November 15, 2019. Christina Koch/NASA/Handout via REUTERS.

Flight Engineers Nick Hague and Christina Koch of NASA go on a spacewalk to work on a set of battery replacements outside the International Space Station March 29, 2019 in this still image from video. REUTERS/NASA

U.S. astronauts Jessica Meir (L) and Christina Koch pose in the International Space Station in a photo released October 17, 2019. NASA/Handout via REUTERS.

Hurricane Dorian is shown from the International Space Station orbiting more than 200 miles above the earth, as it churns in the north-western Caribbean nearing the United States mainland in this photo taken September 2, 2019. Picture taken September 2, 2019. Christina Koch/NASA/Handout via REUTERS.

Specialists help NASA astronaut Christina Koch shortly after landing of the Russian Soyuz MS-13 space capsule in a remote area southeast of Zhezkazgan in the Karaganda region of Kazakhstan, February 6, 2020. Sergei Ilnitsky/Pool via REUTERS.

NASA astronauts Christina Koch and Nick Hague are shown on the International Space Station sending a Fourth of July message home from space in this photo taken July 4, 2019. NASA/Handout via REUTERS.

NASA astronaut Anne McClain assists fellow NASA astronauts Christina Koch (L) and Nick Hague as they verify their U.S. spacesuits are sized correctly and fit properly ahead of a set of upcoming spacewalks at the International Space Station on March 18, 2019. Picture taken on March 18, 2019. Courtesy NASA/Handout via REUTERS.

The Soyuz MS-13 spacecraft is seen as it lands in a remote area near the town of Zhezkazgan, Kazakhstan with Expedition 61 crew members Christina Koch of NASA, Alexander Skvortsov of the Russian space agency Roscosmos, and Luca Parmitano of ESA (European Space Agency) in a remote area southeast of Zhezkazgan in the Karaganda region of Kazakhstan, February 6, 2020. NASA/Bill Ingalls via REUTERS.

The International Space Station (ISS) crew member Christina Koch of the U.S. reacts in a bus before leaving for pre-flight preparation at the Baikonur Cosmodrome, Kazakhstan March 14, 2019.

Photographers take pictures as the Soyuz MS-12 spacecraft carrying the crew formed of Aleksey Ovchinin of Russia, Nick Hague and Christina Koch of the U.S. blasts off to the International Space Station (ISS) from the launchpad at the Baikonur Cosmodrome, Kazakhstan March 15, 2019.

An aurora in the Earth's atmosphere is seen from the International Space Station, in this image published June 10, 2019. Christina Koch/NASA/Handout via REUTERS.

The eye of Hurricane Dorian is shown from the International Space Station orbiting more than 200 miles above the earth, as it churns in the north-western Caribbean nearing the United States mainland in this photo taken September 2, 2019. Picture taken September 2, 2019. Christina Koch/NASA/Handout via REUTERS.

The International Space Station (ISS) crew member Christina Koch of the U.S. smiles after donning space suit check shortly before launch at the Baikonur Cosmodrome, Kazakhstan March 14, 2019.

U.S. astronauts Christina Koch and Jessica Meir step out of the International Space Station (ISS) to attempt the first all-female spacewalk, in this still image taken from NASA video, October 18, 2019. NASA TV/REUTERS.