Christina Koch (/kʊk/ COOK; née Hammock; born January 29, 1979) is an American engineer and NASA astronaut of the class of 2013.

On October 18, 2019, she and Jessica Meir were the first women to participate in an all-female spacewalk to replace a down power control unit located outside of the International Space Station.

[8] Koch was selected as part of the crew for the Artemis II flight, which intends to circle the Moon in 2026 which, if successful, will make her the first woman to travel beyond low Earth orbit.

[12] She has described her time in the South Pole as challenging mentally and physically:[15] "[This] means going months without seeing the sun, with the same crew, and without shipments of mail or fresh food.

[12] She contributed to instruments studying radiation particles for NASA missions, including the Juno and Van Allen Probes.

[12]On March 14, 2019, Koch launched to the International Space Station on Soyuz MS-12, alongside Aleksey Ovchinin and Nick Hague, to join the Expedition 59/60/61 crew.

[19] Koch performed the first all-female spacewalk with Jessica Meir on October 18, as part of a lengthy series of upgrades to the ISS' power systems and physics observatories.

[3] She enjoys backpacking, rock climbing, paddling, sailing, running, yoga, community service, photography, surfing and travel.

[12] In December 2020, Koch was awarded an honorary Doctor of Sciences degree from her alma mater, North Carolina State University.