Thirty-five years to the month since Kathy Sullivan carved her name in the annals of history by becoming America’s first female spacewalker, another record was set for the United States and the world earlier today (Friday, 18 October) when Expedition 61 astronauts Christina Koch and Jessica Meir embarked on the world’s first all-woman Extravehicular Activity (EVA). The duo—with Koch making her fourth career EVA, serving as “EV1”, with red stripes on her space suit for identification, and first-timer spacewalker Meir as “EV2”, in a pure white suit—spent seven hours and 17 minutes outside the International Space Station (ISS) replacing a failed Battery Charge/Discharge Unit (BCDU) and tending to a number of get-ahead tasks. In addition to its obvious significance as the first-ever all-female EVA, today’s U.S. EVA-58 saw Koch jump in the rankings to become the world’s fourth most experienced woman spacewalker.
Although never intended as a gender-focused political stunt, an all-female spacewalk first entered the realms of possibility in March 2019, when NASA revealed its intent to send Expedition 59 astronauts Anne McClain and Christina Koch outside the ISS to help install new batteries onto the station’s P-4 truss. As circumstances transpired, the lack of availability of suitably-sized Extravehicular Mobility Units (EMUs) precluded an all-female EVA at that point in time and the spacewalk was instead done by McClain and her Expedition 59 crewmate Nick Hague. Hopes of sending two women outside at the same time were rekindled a second time on 4 October, when NASA announced that Koch and her newly-arrived Expedition 61 crewmate Jessica Meir would pair up for the fourth of five planned EVAs to remove 12 aging nickel-hydrogen batteries from the P-6 truss and replace them with six upgraded lithium-ion units.
That spacewalk, originally scheduled for 21 October, was postponed earlier this week when the need arose to remove and replace a failed Battery Charge/Discharge Unit (BCDU). Part of the station’s electrical power system, the BCDUs are responsible for regulating the amount of charge to the batteries from the eight Solar Array Wings (SAWs). Two spacewalks, conducted by Expedition 61 astronauts Koch and Drew Morgan, took place on 6 October and 11 October and successfully began the process of removing and replacing the old nickel-hydrogen batteries in the P-6 truss with new lithium-ion units. However, shortly after the completion of the second EVA, the BCDU failed to activate and the remaining three spacewalks were put on hold until it could be replaced. “The station’s overall power supply…remains sufficient for all operations and the failed unit has no impact on the crew’s safety of ongoing laboratory experiments,” NASA explained. “However, the failed power unit does prevent a new lithium-ion battery installed earlier this month from providing additional station power.”