The first man in space happened in 1961 and women first entered space in June of 1963. Today, the first all-female spacewalk happened around the International Space Station. U. S. Astronauts Christina Koch and Jessica Meir are truly making "one giant leap for mankind."The two women are the 14th and 15th women to ever spacewalk, with the very first woman completing a spacewalk in 1984. Koch is a member of the space station team and will complete a total of 11 months at the ISS, the longest term for any female. Meir, however, is a marine biologist by trade and arrived at the ISS approximately a month ago, in preparation for this spacewalk. The women were both graduates of NASA's 2013 astronaut class.The women are replacing a 232-pound battery-charge discharge unit (BCDU), whose job is to help convert solar energy into power for the ISS. In space, the battery may not have any weight, but the women still need to be careful with the replacement because the mass of the object can still cause damage to the space station's delicate systems. Koch replaced a different BCDU earlier this month, but the spacewalk was done with a male counterpart.NASA did not initially plan the all-female spacewalk to be an event. They simply paired the two women together in the rotation of repairs and it was then realized the event would be significant to history. The all-female spacewalk was supposed to happen last spring, until NASA realized they did not have the right sized space suits available. This was recently fixed and with the unsuspecting faulty battery, NASA moved the women's walk up a few days to replace the BCDU accordingly.The women switched their space suits to battery mode as of 7:38 am EDT, signaling the start of their walk. They will be outside of the ISS just under six hours replacing the battery and performing additional preparatory tasks for additional upcoming maintenance. To see the video of the live stream as the women completed their mission, go to nasa.gov.Editor's Note: At the time this was written, we were actively watching the women live in space! They were 250 miles above Southern California and had just completed the battery replacement.