{"id":54620,"date":"2024-02-08T07:42:12","date_gmt":"2024-02-08T07:42:12","guid":{"rendered":"http:\/\/41417542-b905-47cd-9333-85fdb44aa1f1"},"modified":"2024-02-08T08:33:54","modified_gmt":"2024-02-08T08:33:54","slug":"an-astronaut-takes-off-their-helmet-in-space-how-long-do-they-survive","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/an-astronaut-takes-off-their-helmet-in-space-how-long-do-they-survive\/","title":{"rendered":"An astronaut takes off their helmet in space. How long do they survive?"},"content":{"rendered":"

What happens if an astronaut takes off their helmet in space? How long would they survive and what would happen to their body? <\/p>

By Sean Blair\n <\/p>

Published: Thursday, 08 February 2024 at 07:42 AM<\/p>

\n\n

What would happen if an astronaut took off their helmet while in space?<\/p>

Disappointingly for sci-fi writers, realistically it can\u2019t happen.<\/p>

“An astronaut in a pressurised suit cannot remove their helmet by themselves,” notes Herve Stevenin, overseeing ESA\u2019s Extra-Vehicular Activity and Parabolic Flight Training Unit.<\/p>

“Instead this is done by another crew member back in the airlock.”<\/p>

NASA astronaut Jessica Meir pictured during an EVA with fellow astronaut Christina Koch, 18 October 2019. Credit: NASA<\/figcaption><\/figure>
Ok, but let’s assume an astronaut could take off their helmet. How long do they have?<\/strong><\/h2>
Assuming dramatic licence \u2013 or a very wonky spacesuit \u2013 how long would a helmetless astronaut survive?<\/p>
First the good news: contrary to vintage sci-fi, the astronaut won\u2019t immediately die, explode or freeze.<\/p>
“Vacuum is a poor heat conductor,” explains Senior ESA Flight Surgeon Dr. Sergi Vaquer Araujo. “The body will drop in temperature, but it won\u2019t spontaneously turn into a big frozen stick.”<\/p>
Based on animal experiments and some vacuum chamber accidents, an astronaut who has removed their helmet may remain conscious for up to 12 seconds and could survive if re-pressurised within two minutes or less, while running an ever-growing risk of irreversible damage.<\/p>
A spacesuit\u2019s function is not just to supply a spacewalker with oxygen but also to keep their body at sufficient pressure to maintain breathing and other bodily functions.<\/p>
Once that is lost, bad things happen.<\/p>
$\"Sunrise$
Unfiltered sunlight would be a pressing concern for an astronaut without a helmet. This image shows sunrise from space, captured from the International Space Station. Credit: NASA<\/figcaption><\/figure>
Astronaut without a helmet, minute by minute<\/strong><\/h2>
So the astronaut removes their helmet. What happens next?<\/p>
Immediately their unprotected face experiences sunburn from the heavy ultraviolet content of unfiltered sunlight.<\/p>
Our spacewalker, however, will have other issues in mind.<\/p>
Most of all \u2013 counter-intuitively \u2013 the astronaut without a helmet must remember to exhale. Hold their breath and their lungs will expand like a bursting balloon.<\/p>
Keeping their airways open should avoid the worst of this \u2018barotrauma\u2019, although their lungs now become a place where oxygen is venting from (rather than entering) their blood.<\/p>
$\"Ears$
Ears are one organ that would begin to feel the severe effects of an astronaut taking off their helmet in space. Credit: Tara Moore \/ Getty Images<\/figcaption><\/figure>
Parallel air expansion within their ears and sinuses will cause tissue ruptures and possible deafness.<\/p>
In the absence of atmospheric pressure, the moisture coating the astronaut\u2019s eyes, mouth and throat will vaporise.<\/p>
The last sensation of one NASA engineer as he underwent inadvertent decompression in 1966 was the salvia on his tongue boiling away.<\/p>
This vaporisation will in turn cause localised temperature drops and freezing.<\/p>
Liquids within bodily tissues also boil and bubble, triggering painful swellings known as \u2018ebullism\u2019.<\/p>
In 1960, high-altitude balloonist Joseph Kittinger<\/a> had the glove on his pressure suit fail: his hand swelled up to double normal size, returning to normal once he parachuted back.<\/p>
$\"Air$
Air Force Captain Joseph M. Kittinger Jr., just as he starts the jump that set his record breaking 102,800 parachute jump over southern New Mexico, 8 August 1960. Credit: Bettmann \/ Getty Images<\/figcaption><\/figure>
Other bodily fluids will escape if they can, according to one 1964 NASA experiment on dogs: \u201cLacrimation [crying], profuse salivation, urination, projectile vomiting, and defecation were observed. All fluids were bubbling on emission.\u201d (the good news is that most subjects recovered).<\/p>
The most serious threat is the ongoing loss of now-gaseous blood oxygen via the vacuum-exposed lungs, causing hypoxia.<\/p>
Once the first deoxygenated blood reaches the brain the spacewalker\u2019s \u2018time of useful consciousness\u2019 is over.<\/p>
The quoted figure of 12 seconds is optimistic, likely to be reduced by bodily exertions or external factors such as G-forces.<\/p>
When Space Shuttle Columbia<\/a> broke up in 2003, the crew seemed to lose consciousness instantaneously, never even sealing their flight suit visors.<\/p>
So our helmetless astronaut would need their fellow crewmates to save them.<\/p>
Though when ESA astronaut Luca Parmitano had his helmet fill with water during a 2014 spacewalk it took 23 minutes to return him to the airlock \u2013 any helmetless spacewalker would be long dead by then.<\/p>
\u201cThis kind of worst-case scenario has obvious irreversible consequences,\u201d adds Dr. Vaquer.<\/p>
$\"ESA$
ESA astronaut Luca Parmitano during a spacewalk outside the International Space Station, 25 January 2020. Credit: NASA<\/figcaption><\/figure>
What about an astronaut losing a glove?!<\/strong><\/h2>
The closest parallel that trainee astronauts experience is a \u2018glove pop off\u2019, which takes place in NASA\u2019s Neutral Buoyancy Laboratory, the giant swimming pool for spacewalk training.<\/p>
The trainee\u2019s glove is removed so that their spacesuit pressure drops suddenly.<\/p>
The EVA suited trainee is required to exhale as fast as possible to avoid injury from their lungs over-expanding.<\/p>
$\"Samantha$
ESA astronaut Samantha Cristoforetti during underwater training for spacewalks in NASA\u2019s Neutral Buoyancy Laboratory, Houston, USA. Credit: NASA\/ESA<\/figcaption><\/figure>
The aim is to prepare trainees for a suit failing for real underwater.<\/p>
A mild version of this scenario has already happened in orbit.<\/p>
On Shuttle mission STS-37 in 1991, spacewalker Jay Apt inadvertently punctured his glove. He didn\u2019t even notice until afterwards: his own skin plus congealed blood filled the small hole.<\/p> <\/body><\/html>\n
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What happens if an astronaut takes off their helmet in space? How long would they survive and what would happen to their body? <\/p>\n","protected":false},"author":24,"featured_media":54621,"template":"","categories":[1],"acf":{"readingTimeMinutes":"5"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/an-astronaut-takes-off-their-helmet-in-space-how-long-do-they-survive.jpg",1280,853,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/an-astronaut-takes-off-their-helmet-in-space-how-long-do-they-survive-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/an-astronaut-takes-off-their-helmet-in-space-how-long-do-they-survive-300x200.jpg",300,200,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/an-astronaut-takes-off-their-helmet-in-space-how-long-do-they-survive-768x512.jpg",768,512,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/an-astronaut-takes-off-their-helmet-in-space-how-long-do-they-survive-1024x682.jpg",800,533,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/an-astronaut-takes-off-their-helmet-in-space-how-long-do-they-survive.jpg",1280,853,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2024\/02\/an-astronaut-takes-off-their-helmet-in-space-how-long-do-they-survive.jpg",1280,853,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"What happens if an astronaut takes off their helmet in space? How long would they survive and what would happen to their body?","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/54620"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/54621"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=54620"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=54620"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

NASA astronaut Jessica Meir pictured during an EVA with fellow astronaut Christina Koch, 18 October 2019. Credit: NASA<\/figcaption><\/figure>
Ok, but let’s assume an astronaut could take off their helmet. How long do they have?<\/strong><\/h2>
Assuming dramatic licence \u2013 or a very wonky spacesuit \u2013 how long would a helmetless astronaut survive?<\/p>
First the good news: contrary to vintage sci-fi, the astronaut won\u2019t immediately die, explode or freeze.<\/p>
“Vacuum is a poor heat conductor,” explains Senior ESA Flight Surgeon Dr. Sergi Vaquer Araujo. “The body will drop in temperature, but it won\u2019t spontaneously turn into a big frozen stick.”<\/p>
Based on animal experiments and some vacuum chamber accidents, an astronaut who has removed their helmet may remain conscious for up to 12 seconds and could survive if re-pressurised within two minutes or less, while running an ever-growing risk of irreversible damage.<\/p>
A spacesuit\u2019s function is not just to supply a spacewalker with oxygen but also to keep their body at sufficient pressure to maintain breathing and other bodily functions.<\/p>
Once that is lost, bad things happen.<\/p>
$\"Sunrise$
Unfiltered sunlight would be a pressing concern for an astronaut without a helmet. This image shows sunrise from space, captured from the International Space Station. Credit: NASA<\/figcaption><\/figure>
Astronaut without a helmet, minute by minute<\/strong><\/h2>
So the astronaut removes their helmet. What happens next?<\/p>
Immediately their unprotected face experiences sunburn from the heavy ultraviolet content of unfiltered sunlight.<\/p>
Our spacewalker, however, will have other issues in mind.<\/p>
Most of all \u2013 counter-intuitively \u2013 the astronaut without a helmet must remember to exhale. Hold their breath and their lungs will expand like a bursting balloon.<\/p>
Keeping their airways open should avoid the worst of this \u2018barotrauma\u2019, although their lungs now become a place where oxygen is venting from (rather than entering) their blood.<\/p>
$\"Ears$
Ears are one organ that would begin to feel the severe effects of an astronaut taking off their helmet in space. Credit: Tara Moore \/ Getty Images<\/figcaption><\/figure>
Parallel air expansion within their ears and sinuses will cause tissue ruptures and possible deafness.<\/p>
In the absence of atmospheric pressure, the moisture coating the astronaut\u2019s eyes, mouth and throat will vaporise.<\/p>
The last sensation of one NASA engineer as he underwent inadvertent decompression in 1966 was the salvia on his tongue boiling away.<\/p>
This vaporisation will in turn cause localised temperature drops and freezing.<\/p>
Liquids within bodily tissues also boil and bubble, triggering painful swellings known as \u2018ebullism\u2019.<\/p>
In 1960, high-altitude balloonist Joseph Kittinger<\/a> had the glove on his pressure suit fail: his hand swelled up to double normal size, returning to normal once he parachuted back.<\/p>
$\"Air$
Air Force Captain Joseph M. Kittinger Jr., just as he starts the jump that set his record breaking 102,800 parachute jump over southern New Mexico, 8 August 1960. Credit: Bettmann \/ Getty Images<\/figcaption><\/figure>
Other bodily fluids will escape if they can, according to one 1964 NASA experiment on dogs: \u201cLacrimation [crying], profuse salivation, urination, projectile vomiting, and defecation were observed. All fluids were bubbling on emission.\u201d (the good news is that most subjects recovered).<\/p>
The most serious threat is the ongoing loss of now-gaseous blood oxygen via the vacuum-exposed lungs, causing hypoxia.<\/p>
Once the first deoxygenated blood reaches the brain the spacewalker\u2019s \u2018time of useful consciousness\u2019 is over.<\/p>
The quoted figure of 12 seconds is optimistic, likely to be reduced by bodily exertions or external factors such as G-forces.<\/p>
When Space Shuttle Columbia<\/a> broke up in 2003, the crew seemed to lose consciousness instantaneously, never even sealing their flight suit visors.<\/p>
So our helmetless astronaut would need their fellow crewmates to save them.<\/p>
Though when ESA astronaut Luca Parmitano had his helmet fill with water during a 2014 spacewalk it took 23 minutes to return him to the airlock \u2013 any helmetless spacewalker would be long dead by then.<\/p>
\u201cThis kind of worst-case scenario has obvious irreversible consequences,\u201d adds Dr. Vaquer.<\/p>
$\"ESA$
ESA astronaut Luca Parmitano during a spacewalk outside the International Space Station, 25 January 2020. Credit: NASA<\/figcaption><\/figure>
What about an astronaut losing a glove?!<\/strong><\/h2>
The closest parallel that trainee astronauts experience is a \u2018glove pop off\u2019, which takes place in NASA\u2019s Neutral Buoyancy Laboratory, the giant swimming pool for spacewalk training.<\/p>
The trainee\u2019s glove is removed so that their spacesuit pressure drops suddenly.<\/p>
The EVA suited trainee is required to exhale as fast as possible to avoid injury from their lungs over-expanding.<\/p>
$\"Samantha$
ESA astronaut Samantha Cristoforetti during underwater training for spacewalks in NASA\u2019s Neutral Buoyancy Laboratory, Houston, USA. Credit: NASA\/ESA<\/figcaption><\/figure>
The aim is to prepare trainees for a suit failing for real underwater.<\/p>
A mild version of this scenario has already happened in orbit.<\/p>
On Shuttle mission STS-37 in 1991, spacewalker Jay Apt inadvertently punctured his glove. He didn\u2019t even notice until afterwards: his own skin plus congealed blood filled the small hole.<\/p> <\/body><\/html>\n
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