I'm writing a short story about space faring race of people. I want to emphasize how technology has allowed a casual approach to space, making it seem like only a minor inconvenience or hazard.

One way I'd like to show this is with space suits that are as minimal as possible. I'd like for it to be just a gas mask to go with their regular attire; something lightweight to use in emergencies or as needed that creates an airtight seal. (Also suppose that their future™ clothing takes care of sealing up the remaining cavities)

My question is: would this work?

Humans have survived total vacuum with no lasting effect. But in each case this has happened, their lungs have always been at the same ambient pressure as the outside. Since this mask supplies pressure (not necessarily as much as 1 atm; not necessarily air), there will be a non-trivial outward delta-p. Is this viable? Painful? Fatal?

If the latter, is there anything I could do practically to make it work?

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    $\begingroup$ "Humans have survived total vacuum with no lasting effect, but each time this has happened, there was no pressure differential inside to out." ??? If it was a total vacuum, how could there be no pressure differential? $\endgroup$ Commented Apr 22, 2017 at 1:17
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    $\begingroup$ I mean that their lungs, GI tract, etc. were at the same ambient (vaccuum) pressure. Will edit to clarify. $\endgroup$
    – BB ON
    Commented Apr 22, 2017 at 1:39
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    $\begingroup$ Are you looking at emergencies or "casual approach to space?" Emergency equipment is never casual. Also, since you want to have the "future clothing" take care of the vast majority of the purposes of a space suit, you might want to enumerate which parts of a space suit's job you actually want the gas mask to cover. $\endgroup$
    – Cort Ammon
    Commented Apr 22, 2017 at 3:00
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    $\begingroup$ First thing that comes to mind is Star-Lord's mask in Guardians of the Galaxy. $\endgroup$
    – Dittoslash
    Commented Apr 22, 2017 at 7:54
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    $\begingroup$ This site is full of suit ideas, projectrho.com/public_html/rocket/spacesuits.php $\endgroup$
    – John
    Commented Apr 22, 2017 at 12:44

8 Answers 8


First: how little pressure can a human cope with? The Armstrong limit is 0.0618 atmospheres or 60,000 feet altitude. Water boils and we can't have that in our lungs.

At lower pressures the amount of oxygen, even pure oxygen, is not enough. From the above linked article.

At 11,900 m (39,000 ft), breathing pure oxygen through an unsealed face mask, one is breathing the same partial pressure of oxygen as one would experience with regular air at around 3,600 m (11,800 ft) above sea level. At higher altitudes, oxygen must be delivered through a sealed mask with increased pressure, to maintain a physiologically adequate partial pressure pressure of oxygen. If the user does not wear a pressure suit or a counter-pressure garment that restricts the movement of their chest, the high pressure air can cause damage to the lungs.

So we need oxygen under pressure. That is what your space face mask would deliver. Doable?

Pressure in the lungs requires a balancing atmospheric pressure as delivered by a pressurized suit, or by the column of air towering over my house. If you just pump pressurized air in to the lungs, the pressure differential causes barotrauma . Barotrauma happens to people on ventilators when air under too much pressure is used (in an effort to overcome stiff sick lungs and get the O2 in). Barotrauma can happen when a diver breathes pressurized air at depth and then ascends holding breath. The pressurized air in the lungs, no longer balanced by an equal external pressure from the outside water, expands in the lungs. Your chest swells as your lungs increase in size. Hopefully you exhale and let it out! Too much and the air bursts out - either into body tissue spaces outside the lungs or into the bloodstream. That last is an air embolism which can kill or cause a stroke.

But positive pressure ventilation is definitely used, all the time. People on ventilators are often ventilated with air slightly above atmospheric pressure: this is positive end expiratory pressure, or PEEP. It is related to continuous positive airway pressure or CPAP which people use at home to prevent sleep apnea.

So we can breathe pressurized air. Barotrauma occurs when the pressure is too much over ambient. On a ventilator 20 mm Hg PEEP (20 mm Hg over ambient pressure) is when it really starts getting to be too much. Could 20 mm Hg pressure in the space mask deliver enough oxygen? From the above, 39000 feet is 0.19 atmospheres pressure, which is 144 mm Hg. Breathing that much unopposed pressure you would pop.

If only there were some way to make the effective oxygen concentration greater than plain oxygen gas, which you have to have under pressure to get enough in there. Gas is so gaseous. Could one achieve adequate O2 concentration at a very low pressure with some oxygen carrying liquid like perfluorocarbon? Breathing oxygenated liquids is called liquid ventilation. Maybe the system would flood the lungs and face mask with an oxygen carrying liquid, and on reclaiming it into the reservoir with exhalation oxygenate it a lot under pressure / remove CO2, then allow the user to inhale the liquid again.

The Armstrong limit above is 46 mm Hg and so even with the liquid ventilation, body fluids would still be boiling and that has to be bad.

I would like to have this work somehow but I think your people are going to need pressure suits. They can be very sleek, form fitting suits like speed skaters wear. You can put some people wearing them on the front of your paperback.

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    $\begingroup$ "They can be very sleek" - wouldn't some kind of skin-tight elastic work for this? To provide pressure not via gas pressure but from elasticity? Or couldn't it even be their bioengineered skin? $\endgroup$
    – Mołot
    Commented Apr 22, 2017 at 7:55
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    $\begingroup$ Perhaps the skintight suits would be a regular piece of underwear, mandatory for some professions? It could be smart fabric that only constricts when in a low-pressure environment. The more opportunities for a freak fanservice accident, the better. $\endgroup$ Commented Apr 22, 2017 at 10:24
  • $\begingroup$ Nasa is looking at smart clothing which changes its "tightness" so it could be loose and comfortable on ship and tighten down in vacuum to provide physical pressure. . $\endgroup$
    – John
    Commented Apr 22, 2017 at 12:49
  • $\begingroup$ @Molot: I think the skin tight suits would definitely work. If water pressure works and air pressure works why not spandex pressure? Plus more viewers will tune in. $\endgroup$
    – Willk
    Commented Apr 22, 2017 at 22:12
  • $\begingroup$ The spandex would need to be airtight, and be able to lose heat to the outside when not in a vacuum and retain heat when it is, i.e., built in air conditioning is necessary $\endgroup$
    – nzaman
    Commented Apr 23, 2017 at 5:58

No a facemask isn't sufficicient to protect a human like being from the vacuume of space.

First off such a contraption would only provide breathable gas. That is only one of the functions of a space suit.

Such a suit would provide no protection against the vacuum of space, or the extreme temperature differentials experienced during a spacewalk.

Since they are exposed to a breathing gas there will be a positive pressure in their lungs. To contain this positive pressure requires a full space suit. When Joseph Kittinger's was glove failed to pressurize during his balloon jump, it swelled up to twice it's normal size and caused him debilitating pain, taking 3 hours to return to normal size.

  • $\begingroup$ Wouldn't every single bit of exposed skin freeze and the skin itself be damaged? Facemask doesn't even enclose the head. $\endgroup$
    – Kilisi
    Commented Apr 22, 2017 at 3:31
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    $\begingroup$ @kilisi Space is cold but there's not much there to loose heat to. In space suits the primary concern is cooling not heat. $\endgroup$
    – sphennings
    Commented Apr 22, 2017 at 3:34
  • $\begingroup$ Seems ridiculous then to be sending astronauts out in million dollar suits... what were those scientists thinking. Give a scientist a big budget and that's what happens. $\endgroup$
    – Kilisi
    Commented Apr 22, 2017 at 3:37
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    $\begingroup$ @kilisi en.wikipedia.org/wiki/Liquid_Cooling_and_Ventilation_Garment $\endgroup$
    – sphennings
    Commented Apr 22, 2017 at 3:38
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    $\begingroup$ Vacuum is an insulator, it doesn't transfer heat away from anything (there is still heat loss due to radiation, and cooling due to perspiration will work fantastically well). I'd be far more worried about what vacuum does to eardrums and eyes. $\endgroup$
    – Peter
    Commented Apr 22, 2017 at 11:58

As has been pointed out you need more than a mask because you need to contain the pressure also. However, you can do it with a lot less than NASA-issue if you are in a reasonably hospitable environment.

The thing is, the limbs do not need air, merely pressure. A very carefully fit compression garment will protect the arms and legs from vacuum, you only need a pressure vessel around the head and torso. Not only do the arms and legs not need to be completely airtight but there's an actual advantage from making them not perfect--our normal cooling system is by perspiration. If the limbs are a bit porous the body can cool itself.

Such a lightweight suit does not provide cold protection or extreme heat protection, it's acceptable in somewhat controlled environments (say, inside a structure that doesn't have air) but not good if the temperature extremes are too harsh. It also provides very little protection against micrometeorites.

Inside, however, it would be much preferred by the workers as it's not nearly so tiring to use as a regular space suit.

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    $\begingroup$ And it has been developed already - as usual, Wikipedia has the summary: en.wikipedia.org/wiki/Space_activity_suit $\endgroup$ Commented Apr 22, 2017 at 4:26
  • $\begingroup$ The torso does not need a pressure vessel just something like a strong elastic band to keep pressure on the chest. $\endgroup$
    – John
    Commented Apr 22, 2017 at 12:44
  • $\begingroup$ @John The problem is the torso must expand and contract with breathing. A compression garment will not offer linear resistance to this expansion/contraction and thus can't counteract the air pressure. To breathe the air pressure would have to constantly rise and fall and I think that would be very painful in the ears! $\endgroup$ Commented Apr 22, 2017 at 20:52
  • $\begingroup$ what makes you think it would not offer enough resistance? The chest just need enough pressure pushing in to counteract the air pressure pushing out, that pressure can be air pressure or mechanical pressure. As long as the helmet is pressurized the ears should never notice. $\endgroup$
    – John
    Commented Apr 23, 2017 at 0:40
  • $\begingroup$ @John The problem is that it would not offer even resistance. You need the same resistance at full inhalation as at full exhalation--something no stretchy material will provide. $\endgroup$ Commented Apr 23, 2017 at 5:27

Living humans have been exposed to the vacuum of space before, in a very unfortunate accident.

[...] they found all three men in their couches, motionless, with dark-blue patches on their faces and trails of blood from their noses and ears [...]

[...] Flight recorder data from the single cosmonaut outfitted with biomedical sensors showed cardiac arrest occurred within 40 seconds of pressure loss. [...]

The autopsies took place at Burdenko Military Hospital and found that the cause of death proper for the cosmonauts was hemorrhaging of the blood vessels in the brain, with lesser amounts of bleeding under their skin, in the inner ear, and in the nasal cavity, all of which occurred as exposure to a vacuum environment caused the oxygen and nitrogen in their bloodstreams to bubble and rupture vessels. Their blood was also found to contain heavy concentrations of lactic acid, a sign of extreme physiologic stress. Although they could have remained conscious for almost a minute after decompression began, less than 20 seconds would have passed before the effects of oxygen starvation made it impossible for them to function.

I'm not a medical doctor, but I'd assume all of the above to happen even if they wore a gas mask, except for the being unable to function due to oxygen deprivation after 20 seconds, and the subsequent loss of consciousness.

However, it's prudent to acknowledge that various sources state the cause of death as...

the cosmonauts had died of asphyxiation

... which a pressurized gas mask that's specifically designed to work in ultra low pressure environments presumably could have prevented.


These are not humans, but a race of your invention. So just make them more tolerant of vacuum conditions. Like the created humaniform beings in Stross’ Saturn's Children who don’t need a suit to cross vacuum briefly, and need only warm coats on Mars.


Yes - it will work

In case if - Also suppose that their future™ clothing takes care of sealing up the remaining cavities

In the case, you do not need a gas mask, as strong plastic-bag-like stuff from the same material as clothing will be sufficient.

But basically, you need some kind of smart matter. It can be not the gray goo like smart matter, but CNT fiber like smart matter will be sufficient for the task.

It can work on any principles from the links from the answer combining protection and muscle amplification functions.
It can be transparent or appear as transparent to the user.

It might work as a thin layer on the skin surface of the user, it might have some construction in the lungs and guts of the user etc.
There are numerous ways to implement the needed for you functionality.

It might be made from CNT or DNT (Diamond Nanothread).

So yes causality of vacuum is totally possible.

As a way to build in computer-like structures in the construction, you might refer to Nanostructure-Based Vacuum Channel Transistor should work well with those types of materials.


You can have the people genetically engineered to have vacuum-resistant lungs and maybe cardiovascular system, so they can use a face mask and not get an embolism.

Another possibility is Kurzweil's artificial red blood cells, which could keep them oxygenated for minutes to hours without breathing.


A 'gas mask' usually means a respirator which consists of a mask and filters, sometimes exhalation mask to reduce breathing effort. Depending on type the filters can provide protection against particles, aerosols and some types of vapour (usually things like organic solvents with a relatively high molecular weight).

What this type of mask won't do is provide any protection at all against a lack of oxygen.

Having said that some types of mask can be fitted with can replace the filters with a regulator connected to a pressurised air supply, the SCBA systems used by firefighter are based on this principal.

You can also get emergency systems designed for escape purposes eg in confined spaces ect. These only give a few minutes or air and aren't necessarily designed to work in a vacuum but would probably be better than nothing and are deigned to be very simple to use in an emergency. .

Another real world analogy is the emergency oxygen masks in passenger aircraft which are designed to keep passengers alive if the cabin depressurised.

These sort of systems would be OK say in the event of a hull breech when you just need to stay alive for long enough to patch the leak or escape through a hatch to another compartment.

If there is a risk of ending up in space by accident, say if there is a decompression and no immediate escape route it might be worthwhile haveing a suit which can self inflate (a bit like a self-inflating life jacket) in tandem with an emergency breathing mask. This would provide additional protection from the effects of reduced pressure on tissues at the expense of making you effectively immobile but that might be ok if you just need to float around for half an hour until a rescue team in proper space suits can arrive. As long as the suit and mask are separate you don't even need the inflating gas to be air.

You could also have a suit which provide mechanical compression instead of inflating.

In a space station or space craft it might make as much sense to have emergency masks and refuge pods dotted around in the same way that fire extinguishers are in contemporary buildings.


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