NASA First All Female Spacewalk Is Happening This Week: Here's Everything You Need to Know

The first ever all-female spacewalk will take place this week.

In March, NASA cancelled its first attempt following a problem with the sizing of the astronauts' spacesuits. The historic event was initially rescheduled to take place on October 21—but NASA Administrator Jim Bridenstine tweeted an update Tuesday, announcing the walk had been pushed forward to Thursday or Friday.

This was because one of the controllers orbiting the International Space Station (ISS) has failed and needs its batteries replaced. The two astronauts involved in the walk, Christina Koch and Jessica Meir, will replace that battery.

Here's everything you need to know about the historic spacewalk:

space walk
The first female-female spacewalk has now been scheduled to take place later this week. Pictured: An astronaut on a spacewalk. NASA/Getty

When is the spacewalk taking place?

The spacewalk will be on either Thursday or Friday—October 17 or 18. It will begin at 7.50 a.m. and it is estimated the spacewalk will last about 6.5 hours. Live coverage of the event will begin at 6.30 a.m.

What is a spacewalk?

As NASA explains on its official website, a spacewalk describes any event that involves an astronaut leaving the spacecraft while still in space. It can also be called an EVA, short for extravehicular activity.

The very first person to take a spacewalk was Alexei Leonov, a cosmonaut from the Soviet Union, in March 1965. Ed White became the first American to perform a spacewalk, following in Leonov's footsteps three months later.

Today, there are several reasons why an astronaut might partake in a spacewalk—from performing science experiments to repair work.

Who are the astronauts involved?

Christina Koch
Christina Koch will be one half of the first all-female spacewalk. Nasa

Christina Hammock Koch, 40, and Jessica U. Meir, 42, were both selected to be part of the eight-member 21st NASA astronaut class in 2013.

Koch, from Michigan, is part of three space expeditions and is scheduled to remain in orbit until February 2020, when she will set the record for the longest time a woman has ever spent in space. Prior to her job as an astronaut, Koch worked as an engineer for government organizations including the Goddard Space Flight Center, the United States Antarctic Program and National Oceanic and Atmospheric Administration.

Meir, born and raised in Maine, is a private pilot with a background in science and physiology, having worked as an assistant professor at the Harvard Medical School/Massachusetts General Hospital, where she studied the physiology of animals in extreme environments. At NASA, she has served as an aquanaut—divers who live and work underwater for extended periods of time—at the world's only undersea research station, 'Aquarius'.

Jessica Meir
Jessica Meir will complete her first spacewalk this week. NASA

Were Koch and Meir involved in the cancelled all-female spacewalk?

Koch was. Meir wasn't. The spacewalk that was due to take place on March 29 included Koch and another female astronaut, Anne McClain. However, the event suffered a last minute cancellation, in part, due to a shortage of medium-sized space suits.

In the end, Koch took the one medium-size torso and completed the walk with a male NASA astronaut, Nick Hague, becoming the fourteenth female to space walk. It wasn't all bad news for McClain, who had become the thirteenth female the week before.

In response to the news that the spacewalk will be taking place this week, McClain—who has been back on Earth since June—tweeted: "Third spacewalk in a busy season of spacewalks this week. Date is unknown [because] the task was unforeseen: replacing a unit that failed during power-ups of new batteries. Very good that we have four expert spacewalkers on board to shoulder this tough task. They are the A-team!"

What will they be doing?

Koch and Meir will replace a power controller after it failed over the weekend. This follows a similar malfunction to one April shortly after a battery-pack had been swapped, Space.com reports.

crew of NASA's Challenger mission
On October 11 1984, astronaut Kathryn Sullivan (pictured: bottom row, second to left) completed a spacewalk, becoming the first U.S. woman to do so. NASA/Interim Archives//Getty

Why is an all-female spacewalk such a big deal?

In 50-years of spacewalks, there have been male-female and male-male spacewalks but never a female-female spacewalk.

The first woman to spacewalk, Svetlana Savitskaya, did so in 1984—nineteen years after Leonov. To this day, the number of women who can add spacewalker to their list of achievements still trails behind the number of men. Indeed, this week, Meir will become only the fifteenth woman to spacewalk. To put that into perspective, 12 men called Michael have completed a spacewalk, as Mika McKinnon pointed out in an article for Newsweek in March.

This all-female mission is thought by many to represent a historic—but long overdue—milestone for female astronauts, and women more generally.

"Countless young girls across the country will witness this moment and understand that the sky is truly their limit," presidential candidate Kamala Harris tweeted. "I can't wait."

NASA First All Female Spacewalk Is Happening This Week: Here's Everything You Need to Know | Tech & Science