Is there any real technology, experimental or conceptual, that can prolong a person's survivability in outer space in case of sudden life support failure? Something that is also easy to wear or implement for day-to-day activity? Something that you keep on your person in the spaceship/station on all time that, in case of a hull breach or similar disasters, can help you survive long enough until help arrives?
It depends very much on the exact circumstances. Are we talking shirt sleeves to vacuum in 3 seconds or a catastrophic failure of the life support system leading to build-up of carbon dioxide and depletion of oxygen over minutes or hours? And how long before help arrives minutes hours or days? All of these things are critical.
Worst case scenario immediate decompression: Survival unlikely. Your only hope would be some sort of automated device like air bags in a car but I don’t know how you could arrange that to work. There would also be a lot of dangerous fast moving debris and high wind speed as the atmosphere rushed out together with massive shock effects on the body.
If decompression takes at least 30 seconds: I suggest that survival chances would be fair in most cases assuming that training is given. You would have to carry a deflated version of this and climb into it and seal it quickly. You might live for an hour perhaps a bit lot longer. With modifications that time could probably be extended at the cost of making the thing you have to carry (back pack?) a little more bulky.
If decompression takes a minute or more, or the atmosphere remains breathable for a minute or more: survival chances would be very good using the same method.
Humans can probably remain conscious in a vacuum for up to 15 seconds and might survive for a minute or two before death. That said it would be a horrific experience and you would be incapacitated almost immediately.
This Scientific American article might be of interest concerning NASA experiments on dogs and accidental human exposure to vacuum (warning this contains some rather gruesome descriptions)
You may be interested in anti-puncture technology used for pneumatic tires such as bike tube slime. Tire slime is is a liquid when in the tire, but 'sets' when exposed to air. In doing so it seals small leaks. I believe similar systems were at one stage proposed for the ISS. I could see some sort of expanding foam being good for this task in a spaceship - the drop in pressure causing it to expand and set. Similarly, in one sci-fi universe (maybe an Arthur C Clarke? I can't remember) they had airborne equivalent. Lots of lightweight particles/string/aerogel things floated around. When a hull breach occured, they would be sucked into the hole.
System modularity also applies. How do ships and submarines stay afloat in the case of a leak? Bulkheads that can shut off damaged parts of the vessel. This is a staple of sci-fi ship design.....
Aircraft have drop-down air-supplies in case of cabin pressure loss. Some back of the envelope calculations I did a couple years back suggest passengers would get 'the bends' (can anyone confirm/deny this?) and this would only be worse in space. None the less, there are numerous safety systems that already exist that can be applied to a future commercial spacecraft.
For an individual? Not so much. There are three issues:
- pressure difference
Oxygen could easily be provided/available. Divers tanks exist, canned air for climbing Mt Everest exists, and I wouldn't be surprised if something like the jedi breathing device: http://www.starwars.com/databank/jedi-breathing-device is possible at some point - though how you keep it in the guys mouth, and how you stop air exiting his nose is an issue. Probably some sort of face mask is better.
Your major issue is pressure difference. Without compensation, this causes the air in the lungs to expand and rupture the internal tissues (worse now we have a breathing device), and causes the water on your skin to sublimate. In the space suits used by NASA this is dealt with by pressurising the air around the person (inflating the space suit), but more modern concepts have had a form-fitting space-suit that applies pressure directly. Of course, the suit should still be air-tight over most of the surface.
The final issue is temperature. Your survivor needs both heating and cooling. Think about how hot you get standing in the full sun. Now imagine that there wasn't an atmosphere to attenuate the sunlight. But on the side in shadow you probably need heating. 100W over a 2m black body sits at 172Kelvin - well below freezing. But given that your guy is has a face mask and is wearing special clothing, why not just put him in a (slightly futuristic) space suit.
In the book 'Stealing Light' by Gary Gibson, the main protagonist has alien tech implanted that caused a thin black film of handwavium to cover their entire body (including interior of mouth, throat and presumably lungs) that would auto-deploy on exposure to vacuum. (And it also auto-deployed to absorb large kinetic impacts). So I suppose the other option is to throw in nanobots, biotech, or some other handwave mechanism.
You may also want to read up on the sorts of failures that occur on spacecraft. To my knowledge there was only one case of sudden fatal decompression - the Soyuz 11. In that case it was a valve to a jettisoned part of the capsule that had become stuck open, not any sort of 'hull breach'. In any case, sudden depresurisation is considered something of a design flaw in spacecraft.