Changing Planet

The Four Biggest Risks for Conducting a Spacewalk

Astronaut Luca Parmitano just before aborting the spacewalk. Video still from NASA TV via AFP/Getty Images
Astronaut Luca Parmitano just before aborting the spacewalk. Video still from NASA TV via AFP/Getty Images

An hour into this morning’s scheduled six-hour-long spacewalk to do maintenance work on the International Space Station, astronaut Luca Parmitano’s helmet began inexplicably filling with water.

At first Parmitano, a major in the Italian Air Force, notified ground controllers that he was feeling something unusual on the back of his head.

“My head is really wet and I have a feeling it’s increasing,” Parmitano told  flight controllers on the ground in Houston.

But as the water began to accumulate further, it clearly became more than just a nuisance.

“It’s too much … Now it’s in my eyes,” he relayed.

Ground controllers became concerned that Parmitano could choke on the floating blobs of water, so the spacewalk was immediately halted. Parmitano was then assisted back to the airlock by American Christopher Cassidy, a veteran spacewalker. Once fellow crewmates removed his helmet, they noticed that it contained quite a bit of water — as much as half a liter or 2 cups.

As of Tuesday, NASA is still trying to figure out the exact source of the water.

Astronauts like Parmitano constantly train for various emergency scenarios that may crop up during walks outside the International Space Station. But there are risks involved in the activity, including:

  1. Suit leaks
    Micro-meteors or tiny shards of metal  – even those the size of a grain of sand – could cause a puncture and create a catastrophic leak in the spacesuit. Spacewalkers conduct regular examinations of their gloves and suit for leaks while on spacewalks.
  2. Decompression sickness or ‘the bends’
    If an astronaut puts on his/her spacesuit too quickly and then heads outside the station, there’s reason for alarm. Because of the rapid change in air pressure, nitrogen gas bubbles would expand in their blood vessels, causing severe pain, cramping and even paralysis or death. To prevent decompression sickness astronauts undergo a denitrogenation process prior to all spacewalks because the ambient pressure in their spacesuits is much lower than inside the space station.
  3. Exhaustion-loss of consciousness
    Despite having its own heating/cooling system, spacesuits can get really hot, especially when astronauts are conducting physically demanding walks that go on for many hours. Ground controllers therefore monitor astronaut vital signs making sure they breathing regularly and don’t overheat and pass out.
  4. Accidental detachment from spaceship
    Astronauts go through countless hours of training for spacewalks to familiarize themselves with the exact route they will take once leaving the airlock. Spacesuits are directly tethered to the ISS. However if a spacesuit would detach somehow, there’s a way back in: NASA spacesuits all have mini-jet packs allowing the spacewalker to float back to the station.


Check out more cool NASA facts on spacesuits and spacewalks.


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Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.
  • Paul Felix Schott

    Its a lot safer on the ground of Earth, well maybe not in the near coming times?

    Very soon all will look to the Heavens above.

    (C/2012 S1) will give a show no one will forget.

    Every one on Earth can track and see most all NEAR EARTH OBJECTS at


    What a view the International Space Station will get more then a eye full of C/2012 S1.

    Largest ever seen in the last 200 years or more, Moon Impact Explosion March 17, 2013.

    More small ones Asteroids to Impact, you do not want to be by tall building
    if a big enough one impact the earth most all the tall building if not all will

    Fathers and Mothers take your children to a ” STAR PARTY ” its a gathering of Astronomers some amateur some new to it and many of us have been looking to the Heavens for many years. There are many a Star Party all over this planet.

    From………… Maui Space Surveillance Site Complex (MSSSC)

    Or from any of the hills or beaches in the Hawaii Islands at night if you look long enough you will see one, and some nights many of Shooting Stars. People from all over Earth come to the Islands many of them Astronomers.

    Astronomers from around the world at Dillingham Air Field in Hawaii All are welcome to Hawaiian Astronomical Society Star Party to Look to the Heavens Above. With Many of us that fly in them.

    Father like son both Archimedes and his Father Phidias the Astronomer were
    well know to all wise men of their day that studied the Heavens Above. Long ago
    Wicked men dried to wipe out Archimedes and his Father Phidias from the History

    More small ones very likely, large ones less likely without notice
    with all the eyes looking to the Heavens Above.

  • Kathryn Love

    I am so glad there was no serious problem causing harm. The work done in space may lead to many helpful lessons about how to treat our only home. Earth.

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