What is a Spacewalk and How is it Conducted?

by Carson

A spacewalk isn’t a peaceful stroll in space. In fact, some very complex things happen during a spacewalk, and there is always a firm technical reason to conduct it. Let’s find out what a spacewalk is and how it works.

What is a Spacewalk?

Spacewalk is known as extravehicular activity (EVA). This is when one or more astronauts move outside their spacecraft to conduct some maintenance, like fixing, installing, or uninstalling items inaccessible inside the spacecraft.

No one has ever died in a spacewalk, but it is an extremely risky operation. Therefore, a lot of safety measures are applied, which will be explained below.

Ensuring that the Astronauts are Safe

To make sure astronauts safely work outside and return to the spacecraft, there are safety measures that cover all situations except for the very rare ones.

Firstly, all astronauts must wear spacesuits before going on a spacewalk. This is a pressurized device that can support an astronaut’s life for hours at a time. There is no air in space, and your blood would boil if you go to that environment due to the lack of pressure.

Secondly, there must be a tether to connect the spacecraft and the astronaut. This ensures that the astronauts won’t float away, which creates all sorts of terrible things. But suppose all connections fail at the same time. In that case, the astronaut still has a solution in his/her spacesuit, the Simplified Aid for Extravehicular activity Rescue (SAFER). It is a jetpack with rocket thrusters and fuel tanks to propel the astronauts back to the spacecraft. However, the system is not autonomous, so the astronauts need some knowledge about orbital mechanics to send themselves back to the spacecraft successfully.

Of course, all of those systems must be tested before they are installed and checked thoroughly to ensure they’re in top performance when the astronaut goes out into space. And the astronaut needs to practice spacewalking underwater, too. This mimics the weightless environment in space through buoyancy.


If you open a door in space, all air from the cabin will be sucked out due to the difference in pressure. Therefore, airlocks exist between the main cabin and outer space. It can either be pressurized or depressurized. When the air in the airlock is slowly removed, the cabin is not affected. There must be a time where both doors are safely closed, or all air could be pulled out of the cabin once both doors are open.

How an airlock works
Image Credit: Canva

Interestingly, what astronauts are breathing in the spacesuits is pure oxygen. Therefore, the astronauts need to wait for a few hours before going to space after putting on their spacesuits to ensure no gas bubbles are created from the release of nitrogen in the body.


Now you know spacewalks are not your regular casual walk, right? Conducting spacewalks require complex operations, safety measures, and a very technical reason. If you want to learn more, please visit the websites in the references below.

References and Credits

  1. (2020, November 8). What Is a Spacewalk? Learn Why Astronauts Perform Spacewalks and How Astronauts Train for Spacewalks. Retrieved June 27, 2021, from https://www.masterclass.com/articles/what-is-a-spacewalk-learn-why-astronauts-perform-spacewalks-and-how-astronauts-train-for-spacewalks
  2. Flint Wild. (2020, July 27). What Is a Spacewalk? Retrieved June 27, 2021, from https://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-a-spacewalk-k4.html
  3. Paola Rosa-Aquino. (2020, August 26). Spacewalks: How they work and major milestones | Space. Retrieved June 27, 2021, from https://www.space.com/spacewalk-history.html
  4. Quora. (2017, August 15). What Are Astronauts Trained To Do If They Start Floating Away From The ISS? Retrieved June 27, 2021, from https://www.forbes.com/sites/quora/2017/08/15/what-are-astronauts-trained-to-do-if-they-start-floating-away-from-the-iss/
  5. Erik Sofge. (2013, September 30). What Happens If An Astronaut Floats Off In Space? Retrieved June 27, 2021, from https://www.popsci.com/technology/article/2013-09/what-happens-if-astronaut-floats-space/
  6. Bjorn Carey. (2010, December 10). FYI: How Would NASA Rescue An Astronaut Who Floated Away …. Retrieved June 27, 2021, from https://www.popsci.com/science/article/2010-11/fyi-how-would-nasa-rescue-astronaut-who-floated-away-international-space-station/
  7. (n.d.). Space Educators’ Handbook — The Spacesuit. Retrieved June 27, 2021, from https://er.jsc.nasa.gov/seh/suitnasa.html

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