# How long could you survive in space without a spacesuit?

#### unclefishbits

How long could a person survive if thrust into the harsh vacuum of outer space? The short answer is, not very long.

How long could you survive in space without a spacesuit? : Read more

The lung full of air as error, aside, I think you just need to have the bright idea to find a passing spaceship and get rescued by it.

"The Hitch Hiker's Guide to the Galaxy says that if you hold a lungful of air you can survive in the total vacuum of space for about thirty seconds. However it goes on to say that what with space being the mind boggling size it is the chances of getting picked up by another ship within those thirty seconds are two to the power of two hundred and sixty-seven thousand seven hundred and nine to one against.

By a totally staggering coincidence that is also the telephone number of an Islington flat where Arthur once went to a very good party and met a very nice girl whom he totally failed to get off with — she went off with a gatecrasher.

Though the planet Earth, the Islington flat and the telephone have all now been demolished, it is comforting to reflect that they are all in some small way commemorated by the fact that twenty-nine seconds later Ford and Arthur were rescued".

#### Bear

Grisly. Unless there are brown bears in space.

bolide

#### MrD

How long could a person survive if thrust into the harsh vacuum of outer space? The short answer is, not very long.

How long could you survive in space without a spacesuit? : Read more
When I saw Kubrick's 2001 in 1968 at a first run theater in Wash DC, they gave out a short pamphlet that explained the science between Dave's transfer from his EVA pod to the emergency airlock without a spacesuit helmet to let viewers know it was scientifically possible.

DrZacharySmith

#### DrZacharySmith

The title of the article is "how long could you survive in space without a spacesuit". Not long is not a valid answer. Specific answer. Oh, and yeah, if you didn't exhale before stepping into vacuum your lungs would explode. Corollary question, would your eyes explode if you were in a vacuum?

1/10: Surprisingly, given the journalist's and the quoted scientist's credentials, the article is mostly wrong, or at least misleading, even in the context of accidental exposure, and certainly in a novel context of hypothetical (and feasible) deliberate managed exposure by selected and trained individuals.
The article sadly repeats and recycles vague but sensational received wisdoms published many times before online and in print, adding no new facts, figures, evidence or insights and missing a new frontier of human potential.
Rapid (Explosive) Decompression Emergencies in Pressure-Suited Subjects (1960s NASA report title) are not the only possible contexts to pose the question in the article's title.

2/10: The pressure difference between standard surface pressure and the vacuum is of course 1 atmosphere, the same as the difference between a modest 10 metre water depth and the surface. It is only necessary to half-exhale before exposure to the vacuum, because the lung's contents, a mix of air (or oxygen), CO2 and water vapour will only double in size. No big deal to SCUBA and free-divers! No "expanding and rupturing your lungs, tearing them apart [that] would cause boiling and bubbling of your blood, which immediately will cause embolism and have a fatal impact on your body". No "need to empty your lungs as much as possible", but you do need to close your glottis.

3/10: "Bodily fluids, such as saliva and tears" might "begin to boil". But not (with tears) if the subject closes their eyes or wears scleral or "sclera" contact lenses, lubricated with a non-boiling fluid. And not (with saliva) if the subject keeps their mouth closed! Holding or pegging the nose would be protect the nasal mucous membranes. The ear canals could also be plugged to protect the inner ear, with customised earbuds also handy for comms. Besides, at zero pressure and at body-surface temperature, boiling is not the same as scalding, and would likely be experienced as a cooling fizzing sensation. Not "deadly issues"! Nor would your eyes explode.

4/10: "Within a very short time, a matter of 10 to 15 seconds, you will become unconscious because of a lack of oxygen"? No. Trained breath-holders in the fields of free-diving and competitive apnea have achieved records of over 24 minutes after pre-breathing 100% oxygen, and over 11 minutes (man) or 9 minutes (woman) without, so a selected and trained volunteer can likely achieve at least half these times - more than enough to re-enter an airlock, or remain in a terrestrial lab vacuum chamber, and re-pressurise.

5/10: Some physiological side-effects of zero pressure could be mitigate with a porous elastane (Spandex/Lycra) or similar full-body 'Spiderman'-type elastic suit. Nothing drastic should happen to the skin specifically, in the absence of air pressure. As the article states, the skin is "elastic enough to cope with the pressure change".
Valsalva-type manoeuvres could potentially maintain internal body pressure (which, like its temperature, is not uniform) at above the Armstrong limit.

6/10: Temperature is not the same phenomenon in a vacuum as in air, with no conduction or convection - think of a Thermos or vacuum flask.
While highly advisable to avoid sunshine, a few seconds' or minutes' exposure would not cause thermal burning - it's just very bright light - only UV sunburn, and a special strong sunblock cream could minimise that. Tinted or rapid photochromic contact lenses would be advisable.
As for the cold, a human body will slowly radiate heat, but it will probably be many minutes before becoming cold enough for shivering to start, and very many more before hypothermia sets in. A stretch suit with an insulation layer would greatly reduce thermal radiation losses, to the point of being barely a problem, given normal metabolic heat production or a few simple exercises.

7/10: As with solar radiation, solar flare particles will likely be blocked by the suitably deployed sun shield or vehicle body.
The extremely low short-term risk of a micrometeorite strike can be further mitigated at a space station or module by remaining in the lee of the vessel or of a shield, forward of the subject relative to the orbit.

8/10: Relevant fields of theoretical and empirical knowledge and training include:
• High-altitude mountaineering, e.g. Himalayan ascents without oxygen - some individuals turn out to be better suited than others, and most acquire an additional adaptive capacity to work and remain in very low oxygen partial pressures (Mt Everest summit 1/3 of the PaO2 at sea level) or above (publications by and personal communication to me from John West, eminent respiratory physiologist with space and Everest experience);
• SCUBA diving, free-diving and competitive apnea;
• Mindfulness and physiological and emotional self-regulation (already in the free-diving skill-set).

9/10: In my view, a selected and trained breath-holding human could be de-pressurised quickly (in tens of seconds) to zero and be re-pressurised after up to five minutes in a space station airlock, or safely in a terrestrial space medicine lab, with no ill effects.
Further, I think they could conceivably remain in the vacuum, in a suitable set-up and with an 'umbilical' very-low-pressure breathing tube, for as long as a complete International Space Station orbit (93 minutes), while wearing a full-body but porous stretch suit etc., or possibly even largely unclothed.

10/10: This would make an interesting terrestrial research project, perhaps for advanced space medicine students. It could add to human knowledge at a novel frontier, and contribute to the evolution of space suit design and astronautical emergency procedures.

#### Xheesie

9/10: In my view, a selected and trained breath-holding human could be de-pressurised quickly (in tens of seconds) to zero and be re-pressurised after up to five minutes in a space station airlock, or safely in a terrestrial space medicine lab, with no ill effects.
Further, I think they could conceivably remain in the vacuum, in a suitable set-up and with an 'umbilical' very-low-pressure breathing tube, for as long as a complete International Space Station orbit (93 minutes), while wearing a full-body but porous stretch suit etc., or possibly even largely unclothed.
WOW!!! You mean I could survive A WHOLE BIG WHOPPING 24 minutes WITHOUT a space suit? WHOOPEEE!! Call Uncle Elon, bring the kids, grab your flip-flops and sunglasses, we're headed to MARS where the beaches aren't crowded. See ya there in about 30 minutes!!

#### Xheesie

Hah hah haaah--!! The "Space Man" in the video is more like a professional actor doing a dramatic reading of a script. Plumping up to twice his volume from making such a trip into the void sans pressurized suit would actually benefit him-- NO WAY is this guy any kind of "space man-- " waaay too soft.

#### Unclear Engineer

It seems like this could be rather easily demonstrated on the ISS, using lab rats or some other mammal. It could probably be simulated on Earth to some degree - vacuum is easy, but heat transfer by radiation would be more difficult.

#### Classical Motion

How does one close the glottis?

How does one close the glottis?
OK, Classical Motion, when you cough you close your glottis then release it. Humans can do this from birth onwards. That's also the normal throat action when you hold your breath, though you can also pause your breathing with your glottis open, and when you strain to 'push' at your belly for any reason.

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It seems like this could be rather easily demonstrated on the ISS, using lab rats or some other mammal. It could probably be simulated on Earth to some degree - vacuum is easy, but heat transfer by radiation would be more difficult.
Well, Unclear Engineer, it may be tricky to get an animal to voluntarily hold its breath half-full, or at all, to prepare for being briefly depressurised. Trained human subjects are required, to investigate deliberate managed depressurisation.

But it is straightforward to measure the radiative heat loss of a warm or heated object, including one made of flesh, in a vacuum chamber, surrounded by deeply refrigerated surfaces. And the results can be calculated anyway using known physical and physiological principles and data.

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WOW!!! You mean I could survive A WHOLE BIG WHOPPING 24 minutes WITHOUT a space suit? WHOOPEEE!! Call Uncle Elon, bring the kids, grab your flip-flops and sunglasses, we're headed to MARS where the beaches aren't crowded. See ya there in about 30 minutes!!
Thanks Xheesie, I like your spirit! Checklist: return ticket, travel insurance, local currency, bucket and spade, after-sun lotion...

#### Classical Motion

Alright-y. I fail to see or understand any comments about the glottis. But it's ok. I won't wade in space.

#### billslugg

Breathing 100% oxygen works up to an altitude of about 50,000 feet. Above that the partial pressure of O2 is too low and a pressure suit is required. Low oxygen pressure, in an absence of CO2 buildup, will induce hypoxia. Brain will no longer function correctly. In a vacuum you might live as long as you would normally be able to hold your breath, then you would pass out. There is a wide range of ability to hold one's breath. As for indefinite life in a vacuum, no way.

#### Grungy

The photo of the astronaut in the MMU that you used in your story of surviving in a vacuum is Bruce McCandless II, not Robert Stewart.

The red stripes on the LTA and top corners of the PLSS indicate that this is EV-1.
That was how we could tell them apart.
Bruce was EV-1.
Bob was EV-2. His suit had no red stripes.

I was a space suit technician, and helped assemble and test Bruce’s suit, and also did a vacuum chamber test of him in that suit (I was the tech who “rode” the chamber at 10.2 psi with 50% oxygen during the pre-breathe to help purge his body of nitrogen).

LTA - Lower Torso Assembly
PLSS - Primary Life Support Subsystem

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