Are there any rules for Hard Vacuum ? damage, effects etc ?
Vacuum is mentioned in a few items/spell such as the amulet of adaptation which allows you to keep breathing in Vacuum.
But I can't find any actually rules on what exactly Vacuum does mechanically to a character should they somehow encounter deep space
There are such rules! KIND OF!
They lie in a rather odd place - Sorcerer's Starsoul Bloodline in the APG gives an ability which necesitates the rules for hard vacuum.
Starsoul Bloodline - d20 PF SRD
Breaching the Gulf (Sp):
At 15th level, your caster level is increased by 3 when casting spells of the teleportation subschool. In addition, once per day you can teleport a single creature within 30 feet into the void of space if it fails a Will save. The save DC is equal to 10 + 1/2 your sorcerer level + your Charisma modifier. The target can attempt a new saving throw as a full-round action each round to return. While trapped in the airless void, the target suffers 6d6 points of cold damage per round and must hold its breath or begin to suffocate.
Bolding mine.
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That's not right... space isn't that cold. There's this weird dichotomy where in the upper portions of the Earth's atmosphere are intensely cold, then once you are completely past them, you will find yourself wishing you were back in the atmosphere, for more reasons than just "I can't breath".
You see, while you are out in void there is nothing to vent heat to, so you have to provide your own method with which to do that, and sweating doesn't actually cut the mustard here, the air is what makes sweating work, and without something else to shift the heat to, you will just be covered in hot water, and that's assuming you are pressurized somehow. This makes it really bad for vehicles who don't even have sweat to cool themselves off with, they all need extensive cooling systems, especially for the crew.
Now, let's talk about the horrible things vacuum itself has on people. Just read this: http://en.wikipedia.org/wiki/Vacuum#Effects_on_humans_and_animals
Suffice to say, getting dumped in space is way more deadly than 6d6 could ever hope to be, it's significantly closer to dying of suffocation, only much, much faster.
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While trapped in the airless void, the target suffers 6d6 points of cold damage per round and must hold its breath or begin to suffocate.
Actually, taking a breath before entering a hard vacuum is probably one of the worse things you can do. The presure will want to equalize, which means your lungs will explode.
So drop an Alchemist with Internal Alchemist archtype and Mummification Discovery into hard vacuum what happens.
The Alch can hold their breath for hours = CON score and they are immune to cold damage.
The alch can also go into suspended animation and not have to breath at all.
can he survive vacuum for extended periods ?
If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury. Holding your breath is likely to damage your lungs, something scuba divers have to watch out for when ascending, and you'll have eardrum trouble if your Eustachian tubes are badly plugged up, but theory predicts -- and animal experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness.
Mind, this is a hard vacuum, and not a 'soft' vacuum of the extreme upper atmosphere. There, you will alternately freeze and boil as wafts of atmospheric gas at extremely high and low temperatures buffet your body.
Various minor problems (sunburn, possibly "the bends" after a few moments, certainly some [mild, reversible, painless] swelling of skin and underlying tissue) start after ten seconds or so. At some point you lose consciousness from lack of oxygen. Injuries accumulate. After perhaps one or two minutes, you're dying. The limits are not really known.
You do not explode and your blood does not boil because of the containing effect of your skin and circulatory system. You do not instantly freeze because, although the space environment is typically very cold, heat does not transfer away from a body quickly because there is no material to do so. Loss of consciousness occurs only after the body has depleted the supply of oxygen in the blood. If your skin is exposed to direct sunlight without any protection from its intense ultraviolet radiation, you can get a very bad sunburn.
Humans and animals exposed to vacuum will lose consciousness after a few seconds and die of hypoxia within minutes, but the symptoms are not nearly as graphic as commonly depicted in media and popular culture. The reduction in pressure lowers the temperature at which blood and other body fluids boil, but the elastic pressure of blood vessels ensures that this boiling point remains above the internal body temperature of 37°C. Although the blood will not boil, the formation of gas bubbles in bodily fluids at reduced pressures, known as ebullism, is still a concern. The steam may bloat the body to twice its normal size and slow circulation, but tissues are elastic and porous enough to prevent rupture. Swelling and ebullism can be restrained by containment in a flight suit. Shuttle astronauts wear a fitted elastic garment called the Crew Altitude Protection Suit (CAPS) which prevents ebullism at pressures as low as 2 kPa (15 Torr). Rapid boiling will cool the skin and create frost, particularly in the mouth, but this is not a significant hazard.
This means that it is essentially an extreme environmental hazard; being there will kill you within a minute or three, unless you have, ahem, heroic constitution, or regeneration of some kind.
It would also be, after a longer period, incredibly damaging due to the immense amounts of 'hard' radiation you would be receiving.
So drop an Alchemist with Internal Alchemist archtype and Mummification Discovery into hard vacuum what happens.
The Alch can hold their breath for hours = CON score and they are immune to cold damage.
The alch can also go into suspended animation and not have to breath at all.
can he survive vacuum for extended periods ?
He would survive the vacuum, but not the radiation damage. He'd probably gain the discover of '(Malignant) Tumor Familiar", hehehehe
Reading the stuff Kilbourne quoted, one should be in need for some serious medical attention after being exposed to a vacuum - I would guess there's a good chance real world humans could die in the aftermath. Since RPG heroes recover from being sliced with swords, claws and fireballs in one day err... I'd say, for RPG heroes it's not that big of a deal.
What was not quoted is the effect of rapid decompression - this is what let's you explode and stuff. Since it's unlikely that the heroes enter the vacuum with the use of an decompression chamber...
btw, the cold damage can be justified, not by real world logic (since a true vacuum just has no temperature) but by the fact that if the damage type is relevant, it just fits in - who is vulnerable to cold damage? Fire beings. What do fire beings need? Air to burn. It's not perfect in this manner however.
Very cold. The background radiation has a temperature of 3 K.
I'm not that into physics but errr... radiation has a temperature?
interesting subject.
But wouldnt the background radiation also change depending on where you are in the universe? Unless i somehow slept through physics, i seem to recall that the background radiation is a byproduct of the big bang, ie heat leftovers from the explosion. Im pretty sure that a coupple guys that discovered this also recieved a nobel price, but i must say i cant remember their names right now, and no time to look it up becouse of exams.
But wouldnt the background radiation also change depending on where you are in the universe?
Well, yes, there are slight variations in the cosmic background radiation.
The average temperature is 2.725°K ± 0.0002°K.
So, hope you land in one of those nice warms spots that are two ten-thousandths of a degree warmer.
interesting subject.
But wouldnt the background radiation also change depending on where you are in the universe? Unless i somehow slept through physics, i seem to recall that the background radiation is a byproduct of the big bang, ie heat leftovers from the explosion. Im pretty sure that a coupple guys that discovered this also recieved a nobel price, but i must say i cant remember their names right now, and no time to look it up becouse of exams.
Some of the areas are more radiative, yes; but that's background rads. If you're someplace close to a radiative body, like our sun, then it is hot hot hot! You're getting pounded by rads, and there's no way to shield yourself in the vacuum.
If it is a perfect vacuum, as well, you have no way to effectively lose and thermal energy your body may have. There is no material to conduct it from you, and thermal radiation is not efficient enough to do the work quickly. If you were, say, a mummy, you might eventually 'cook' with all the rads rather than freeze (as some would think).
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I recommend using the random chart from the Paranoia module "Clones In Space", with such colourful entries as "explosive decompression", "freeze", "boil" and "combination freeze/boil". :-)
Seems the reason humans in general don't deal with vacuum is mainly due to the water content of our bodies.
without atmospheric pressure to keep water liquid it boils , although boiling is a bit of a misnomer, as people normally associate boiling with heating but boiling is simply liquid->gas
in space ice slowly boils, meaning if you have a chunk of ice in space it will slowly evaporate until there's nothing visible left. of course the water molecule are still in the area but as spread out and dissociated.
In the case of the Mummified Alchemist a Mummy be definition has had all the moisture removed from the body basically leaving a dry husk. although you'd think there'd need to be some sort of fluid medium for the alchemist to be able to move his limbs and not crack, but of course this is where realism departs from fantasy ;)
I'd venture put a dry mummy in space and not much would happen in the short term. there no water to boil or freeze.
interesting discussion but I have to say I was just looking for fantasy rules about a fantasy situation which need not be true to real world physics ;)
in space ice slowly boils, meaning if you have a chunk of ice in space it will slowly evaporate until there's nothing visible left. of course the water molecule are still in the area but as spread out and dissociated.
Incorrect.
Ice boils when exposed to an emission source due to secondary thermal reactions. In other words, ice boils in earth's orbit because of all the photons and radiation hitting it from the sun.
The universe is billions of years old. If ice boiled in a vacuum, then you'd never see a Comet, which is a giant ball of ice. Nor would Pluto be coated in it, nor IO, nor half a dozen other moons (oh, and Saturn wouldn't have rings).
You could use d20 Futures take...
http://www.d20resources.com/future.d20.srd/environments/atmospheric.conditi ons.php
With a subset to radiation damage
http://www.d20resources.com/future.d20.srd/environments/radiation.sickness. php
in space ice slowly boils, meaning if you have a chunk of ice in space it will slowly evaporate until there's nothing visible left. of course the water molecule are still in the area but as spread out and dissociated.
Incorrect.
Ice boils when exposed to an emission source due to secondary thermal reactions. In other words, ice boils in earth's orbit because of all the photons and radiation hitting it from the sun.
The universe is billions of years old. If ice boiled in a vacuum, then you'd never see a Comet, which is a giant ball of ice. Nor would Pluto be coated in it, nor IO, nor half a dozen other moons (oh, and Saturn wouldn't have rings).
its a little more complicated than that but sure if you wanna get technical.
where in the universe is there no energy ? dunno we haven't found it yet. empty space is rated at having a temp of ~3K , 3K is more than 0K (absolute zero) meaning there is energy everywhere in space, not much but enough to excite single molecules under almost no pressure to dissociate themselves from other molecules around them.
i.e. Ice in space loses molecules of itself slowly but surely ALL THE TIME. sure being closer to a star will speed the process up with more available energy, but the process never stops.
Why do you we see comets , rings and planets with water ice ?
First I gotta clear up your Pluto comment its buggin me (apologies) Pluto Ice is nitrogen not water. Meaning not all ice is water that goes for comets and ring too, and energy required to boil/dissociate molecules from a frozen mass varies.
But yes there are water/ice comets and yes they do stick around a long time, because it takes a really really long time for those molecules to "boil off"/dissociate from a larger mass.
Found a number for you ;)
photosputtering erosion velocity of ice in space is estimated to be 400 centimeters per billion years at 1 astronomical unit.
so pretty freaking slow hehehe
but it is happening ;)
But again all I really wanted to know what the Pathfinder mechanics for a creature in a vacuum XD , the conversation while interesting isn't really relevant ;)
No, but the waves of radiation colliding with your molecules produce heat among other things. Just like friction. I mean what do you think, how does the sun heat the earth?
I'm not that into physics but errr... radiation has a temperature?
That's obvious. Point is, we are talking about cooling. To make my question more precise: "Why does one assign an actual temperature to a kind of radiation despise the fact that radiation isn't able to cool something? And how does it matter when talking about heat change in space? (I get suspicious when someone talks about physical laws and then states stuff like <<radiation of temperature 3K>>)"
So it's not really a temperature. Though a body at a temperature higher then 3 K (assuming it comes close enough to a perfect black body) will lose energy due to the difference in radiation (just like in a room at 3K).
Again, "a room at 3K"? "Room" is no sufficient description! One looses much more energy in a room filled with cold water as he would in a room filled with cold air (of the same temperature)
Lose energy okay, but at which rate? I wanna see actual numbers and stuff.
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"Arise, o thread, from the depths of the archives!"
*casts Thread Resurrection*
(Sorry for the thread necromancy, but I dislike starting new threads when there are perfectly good old ones on the topic.)
I'm trying to reconcile the hard vacuum rules from Distant Worlds with the Breaching the Gulf bloodline power (Starsoul Sorcerer bloodline in Advanced Player's Guide), and tie them in together with the holding one's breath/suffocation rules in the Core Rulebook.
What I've arrived at is as follows if a character is exposed suddenly to hard vacuum ...
Explosive decompression causes him to take 3d6 hp damage (no save) on the first round of exposure. (This is taken from Distant Worlds.)
There is no air to breathe but he can hold his breath for (Constitution score x2) rounds, although any standard or full-round action that he takes will reduce that time by an extra round. After this period runs out, he must make a DC 10 Constitution check each round, with the DC increasing each round by +1 for each previous successful Constitution check. As soon as a Constitution check fails, the character begins to suffocate (round 1: drop to 0 hp and go unconscious; round 2: drop to -1 hp and begin dying; round 3: "He's dead, Jim"). (This is taken from the Core Rulebook.)
Simultaneously with this holding his breath/suffocation period, the character is also taking 6d6 hp cold damage (no save) per round. (This is taken from the Starsoul Sorcerer bloodline in the Advanced Player's Guide.)
(In some cases, one could argue for fire damage instead, or make up a new damage type for radiation.)
Sound does not travel, so V component spells could be hard to cast (if not impossible). Certainly the spells which depend upon the target hearing the caster would be impossible. Silent Spell metamagic is your friend in this case. (This is taken - more or less - from Distant Worlds.)
One could also argue for either the Dazzled or the Blinded condition. Or first the one, followed by the other. This might depend upon the location of the character in vacuum. Close to the sun or on the light side of the moon? Probably too much light in some cases.
One could also argue for the Staggered condition, possibly as a result of the explosive decompression.
One could also argue that (instead of the normal Constitution score x2 rounds) the character could only go Constitution score rounds before beginning to suffocate, seeing as holding one's breath in hard vacuum is actually contra-indicated. Or - in the case of someone holding this breath "the wrong way" - instead of reducing the Constitution rounds to x1, allow the x2 but give the character continuous explosive decompression damage each round.
If a creature does not need air to survive, I will assume that it can also survive the decompression and suffocation effects of a vacuum. Cold, fire, or possible radiation damage might affect the creature, depending upon its resistances and immunities. (This is based on the Bone Sages of Eox in Distant Worlds.)
Comments or suggestions? I would like to avoid super-technical discussions, please, as I'm aiming for a usable set of game rules and not trying to pass a physics exam. :)
Still nothing but crickets chirping? I was hoping for some constructive comments ...
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Explosive decompression causes him to take 3d6 hp damage (no save) on the first round of exposure. (This is taken from Distant Worlds.)
I’d probably allow a reflex save for half myself. I would think that if a character immediately expels the air from their lungs they should take little or no damage. The reason for reflex rather than fortitude is that it’s a question of how fast you react and exhale rather than physical endurance.
There is no air to breathe but he can hold his breath for (Constitution score x2) rounds.
As you mention a little later I’d definitely reduce this to their constitution score in rounds rather than double that. Without air in their lungs they definitely shouldn’t be able to hold their breath as long.
I like your idea to let them hold their breath normally and take explosive decompression damage each round. If you do that I wouldn’t allow any save for half damage since their choosing not to exhale. However I think I’d force a fortitude save each round to determine if they are able to keep holding their breath.
Sound does not travel, so V component spells could be hard to cast (if not impossible)
I’d lose the ambiguity, spells with V components would definitely be impossible to cast. A silence spell is much nicer to a person and still prevents them. Also remember that anyone trying to hold their breath normally will be taking constant damage and require concentration checks to cast anything.
One could also argue for the Staggered condition, possibly as a result of the explosive decompression.
Perhaps anyone taking damage from explosive decompression gains the staggered condition for one round? Not as sure about this but it sounds like a reasonable rule.
Thank you, Revel, for your good ideas! (And my apologies for taking so long to reply.)
Here is a slightly revised set of rules for being exposed to vacuum, etc. The soucebook mentions have been removed, as these are now a form of house rules. I hope that they're still pretty deadly.
A surprised or otherwise Flat-footed character takes 3d6 hp damage (no save) from explosive decompression on the first round of exposure to vacuum. If not Flat-footed, then the character can make a Reflex DC 25 save for half damage. Evasion and other abilities cannot reduce or avoid this damage. A character who takes damage from explosive decompression also gains the Staggered condition for his first round of exposure.
There is no air to breathe in a vacuum, but a character can act for Constitution score rounds. Any standard or full-round action that he takes will reduce that time by an extra round.
He could hold his breath for the normal Constitution score x2 rounds before beginning to suffocate, but - as holding one's breath in hard vacuum is actually contra-indicated - the character then suffers continuous explosive decompression damage each round (3d6 hp, no save). In order to continue holding his breath in this way, he must also must make a DC 10 Constitution check each round, with the DC increasing each round by +1 for each previous successful Constitution check. As soon as a Contitution check fails, he expels most of his remaining air, thereby reducing his remaining number of rounds by half (but no longer suffering continuous explosive decompression damage).
After this period runs out, he must make a DC 10 Constitution check each round, with the DC increasing each round by +1 for each previous successful Constitution check. As soon as a Constitution check fails, the character begins to suffocate (round 1: drops to 0 hp and goes Unconscious; round 2: drops to -1 hp and begins Dying; round 3: "He's dead, Jim").
Simultaneously with the explosive decompression and the holding his breath/suffocation period, the character is also taking 6d6 hp cold damage (no save) per round. (In some cases, one could argue for fire damage instead, or make up a new damage type for radiation. Most ground-dwellers would not know about the need for radiation resistance and immunity.)
Sound does not travel, so V component spells would be impossible to cast. Silent Spell metamagic is your friend in this case. Spells which depend upon the target hearing the caster would still be impossible (e.g., language-dependent spells which have no telepathic basis). If the caster has been holding his breath normally, then he must also make a concentration check to cast a spell, as he is taking continuous damage from the continuous explosive decompression.
One could argue for either the Dazzled or the Blinded condition. Or first the one, followed by the other, as the body’s water freezes the eyeballs. This might depend upon the location of the character in vacuum. Close to the sun or on the light side of the moon? Probably too much light in some cases.
If a creature does not need air to survive, it is assumed that it can also survive the decompression and suffocation effects of a vacuum. Cold, fire, or possible radiation damage might affect the creature, depending upon its resistances and immunities.
Distant Worlds was published something like a nine months after this thread was started by Phasics (15 June 2011).
My original post in this thread (#24 on 25 April 2013) lists the various sources for relevant information on "surviving" in vacuum: Distant Worlds, Core Rulebook, and the Starsoul Sorcerer bloodline in the Advanced Player's Guide. What I want is to fuse the revelant rules together into one workable system.
:)
Plus, there is the possibility of ignorant (non space-savvy) PCs finding a gate/portal/whatever to a location or vessel which is currently under hard vacuum conditions. If one doesn't have Planetary Adaptation (Space) prepared in a non-V form, then one could be in trouble. Particularly at low levels.
What about movement? Fly is based on air pressure, do flying carpets fly without air? Can anything move in a straight line at all in the vacuum of space. If you flail around you would spin and drift, but not truly move.
What about movement? Fly is based on air pressure, do flying carpets fly without air? Can anything move in a straight line at all in the vacuum of space. If you flail around you would spin and drift, but not truly move.
If you're using air walk, extraordinary flight, or anything that references 'air' in any way, no. If you're using supernatural or spell-based flight, almost certainly yes.