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Alleine
2007-09-21, 11:51 PM
I would post this in Q&A by RAW, but I'm pretty sure space isn't covered in RAW.

My question, how would you set up rules for space in DnD? I know it isn't exactly made for space adventures and such, especially with the wealth of planes to explore, but I think its a really neat idea. I really like it because unless you enjoy flitting through realities in order to get a more diverse Material Plane, there isn't a whole lot of area for PC's to explore that isn't inherently harmful like the energy planes and elemental planes. To mention nothing of Hell and the like.

I was thinking of a setting for a campaign that would be progressing into space just a little bit, but it seemed extremely unfair for a select few races to be able to run willy-nilly through vacuum doing what they please, specifically warforged. My first idea was to do the opposite of lava, instead of 20d6 fire damage, it'd be 20d6 cold damage for being out in space for too long, but that doesn't make it any easier to explore. Also, how would one get into space? Presumably flight spells or eberron airships wouldn't quite have the oomph to get out of the atmo.

Any help would be appreciated, and yes, I'm well aware there are games that take place in space. Specifically SpellJammer I believe, however I don't have access to those games.

Sorry if my intent is too deeply buried in this wall of text.

Talkkno
2007-09-21, 11:59 PM
Well here's the rules from Saga edition
"Vacuum (Cl8) When a creature is exposed to vacuum, make an attack roll (1d20 +20) against the character's fortitude defense. If the attack succeeds, they the creature takes 1d6 points of damage and moves -2 steps down the condition track. If the attack fails, the creature takes no damage, but moves down -1 step down the condition track. The target cannot move back up the condition track until it is returned to a breathable atmosphere. A creature knocked unconscious by exposure to a vacuum automatically takes a cumulative 1d6 points of damage each round. If this damage ever exceeds the creature's damage threshold, it dies."
Well fortitude defensive is kind of like your saving throw only you add 10 to it and dont roll any dice, condition track is simplified version of the various conditions such as stunning, ablity damage etc.

Jasdoif
2007-09-22, 12:01 AM
Here's D20 Future's take on exposure to vacuum (courtesy of the D20 Modern SRD):


Despite some popular myths, moving into a vacuum does not cause the body to explosively decompress, nor does it cause instant freezing as heat bleeds away from the body. Rather, the primary hazards of surviving in the vacuum of space are the lack of air and exposure to unfiltered ionizing radiation.

On the third round of exposure to vacuum, a creature must succeed on a Constitution check (DC 20) each round or suffer from aeroembolism (“the bends”). A creature that fails the save experiences excruciating pain as small air bubbles form in its bloodstream; such a creature is considered stunned and remains so until returned to normal atmospheric pressure. A creature that fails the Constitution check by 5 or more falls unconscious.

The real danger of vacuum comes from suffocation, though holding one’s breath in vacuum damages the lungs. A character who attempts to hold his breath must make a Constitution check (DC 15) every round; the DC increases by 1 each round, and on a successful check the character takes 1 point of Constitution damage (from the pressure on the linings of his lungs). If the check fails, or when the character simply stops holding his breath, he begins to suffocate. In the next round, he falls unconscious with 0 hit points. The following round, he drops to –1 hit points. On the third round, he drops to –10 hit points and dies.I omitted the mention of radiation to save myself the trouble of having to put the tables into BBcode. If you're interested in that, check Environments under Future here (http://www.wizards.com/default.asp?x=d20/article/msrd).

Combine with the rules for cold weather (http://www.d20srd.org/srd/environment.htm#coldDangers), if desired.

Raolin_Fenix
2007-09-22, 12:07 AM
I would probably impose heavy Con damage with a fort save for half (which should still be heavy), as well as probably 20d6 cold damage (fort half). Really freakin' nasty, I know, but then, so is space; I guess you can survive for like three seconds, if you don't make the mistake of trying to hold your breath (which explodes your lungs). Low-level characters are pretty much auto-screwed; higher-level characters might survive for a couple rounds.

Alleine
2007-09-22, 12:08 AM
Thanks guys! This ought to be really helpful in keeping Warforged from running a space empire with extreme ease. Didn't even think about radiation either!

The only problem now is getting into space, but I think I can handle that aspect.

horseboy
2007-09-22, 12:13 AM
Hehehe! Spelljammer!

kpenguin
2007-09-22, 12:37 AM
Space is cold. Space doesn't have a temperature. To have a temperature, something has to have mass and a vacuum, by definition, is void of mass.

Dervag
2007-09-22, 12:39 AM
The catch is that space isn't really cold as such.

Outer space is a vacuum. Vacuum makes a really good insulator; it's what they use in Thermos bottles and those can keep your coffee hot for most of a day.

In a 'normal' cold environment such as might be found on Earth, you will lose heat by convection- air molecules hit your skin and gain energy, then carry it away and don't come back. That can't happen in a vacuum. So a vacuum won't cause nearly as much harm from cold as lava would from heat. I don't know how it would compare to being dropped in Antarctica wearing the same clothing, but I doubt it would be even that bad. I think you'd die of suffocation long before cold.

Moreover, if you're in direct sunlight you actually gain heat, very fast, as if you were under the blazing sun of the Sahara desert. That would probably be more lethal than the heat.

Here (http://www.sff.net/people/Geoffrey.Landis/vacuum.html) is a link that discusses things fairly intelligently.

Frankly, a warforged ought to be able to function in space for short periods with virtually no handicap whatsoever, especially in the shade. In the heat they'd suffer damage from overheating and thermal expansion.

Anything else that doesn't need to breathe and doesn't rely on dissolved gases in its bloodstream (such as the undead) would also do fairly well in vacuum.

However, prolonged exposure to vacuum could really screw up a warforged that hadn't been explicitly designed to handle vacuum, because machinery designed for air pressure often has parts that stick or freeze together or become brittle and break in vacuum.

Nerd-o-rama
2007-09-22, 12:46 AM
The d20 Modern rules have a strong basis in reality: really, the problem is lack of air and complete absence of pressure. It's not the cold that kills you, it's radiation, suffocation, and bubbles in the bloodstream. Jasdoif's got the right of it.

And no, you don't explode.

kpenguin
2007-09-22, 12:48 AM
It's not the cold that kills you, it's radiation, suffocation, and bubbles in the bloodstream.


The only thing I see there effecting warforged is radiation. However, the lack of air pressure could also be a concern.

Nerd-o-rama
2007-09-22, 12:56 AM
'Forged have biological components (livewood, particularly), that would have similar issues to the human circulatory system, I'm sure. The not breathing is officially a nonissue.

kpenguin
2007-09-22, 12:57 AM
But inevitable space army is okay?

Nerd-o-rama
2007-09-22, 12:58 AM
You mean Inevitables, as in constructs? Sure, why not. The only issue there is locomotion, which requires a vessel or a fly speed or something.

Alleine
2007-09-22, 01:00 AM
This is great, I'm writing up some tentative rules right now. Don't know how good they are and I'll probably post them later for review.

Dervag
2007-09-22, 01:12 AM
'Forged have biological components (livewood, particularly), that would have similar issues to the human circulatory system, I'm sure. The not breathing is officially a nonissue.Does livewood 'breathe', or is it just wood?

Wood could handle exposure to vacuum tolerably well; it doesn't contain a lot of dissolved gas.

Alleine
2007-09-22, 01:15 AM
The only thing about livewood is it is still alive. Meaning there is still liquid in it that will evaporate. It doesn't breathe.

daggaz
2007-09-22, 01:54 AM
Erm... you don't need moving molecules to freeze to death, tho they certaintly do help. The human body radiates a fair amount of heat as well. In a short time, you are gonna be pretty much well frozen if you are in the shade in space.

Alleine
2007-09-22, 02:05 AM
Erm... you don't need moving molecules to freeze to death, tho they certaintly do help. The human body radiates a fair amount of heat as well. In a short time, you are gonna be pretty much well frozen if you are in the shade in space.

You definitely need moving molecules to freeze to death, if they aren't moving then they have no energy and are already "frozen". A construct is going to last longer in space because they don't rely on the weak flesh that meatbags use. Metal, for the most part, will take a lot less damage from exposure to vaccum than flesh will, mostly because metal can't die. Things are a tad different for warforged though.

kpenguin
2007-09-22, 02:15 AM
Erm... you don't need moving molecules to freeze to death, tho they certaintly do help. The human body radiates a fair amount of heat as well. In a short time, you are gonna be pretty much well frozen if you are in the shade in space.

Actually, you do. In order to release internal energy as heat, you need to be in thermal contact with another mass. Since aren't in thermal contact with anything while in a vacuum, the only way to release that internal energy and freeze is to release it kinetically.

Zincorium
2007-09-22, 02:18 AM
You definitely need moving molecules to freeze to death, if they aren't moving then they have no energy and are already "frozen". A construct is going to last longer in space because they don't rely on the weak flesh that meatbags use. Metal, for the most part, will take a lot less damage from exposure to vaccum than flesh will, mostly because metal can't die. Things are a tad different for warforged though.

If they aren't moving they're at absolute zero, something warforged are assuredly not. There is molecular movement in solids at room temperature or even in the blackness of space, and warforged also contain alchemical liquids in containers inside of them according to many descriptions I've read (these are one reason they're still mostly vulnerable to crits). Any molecular movement can be converted into radiant energy, so you'll eventually get very, very cold. Metal is an excellent radiator for equalizing heat.

Warforged will be able to operate in space for a while, which is a lot more than humans can say, but they're not hardened for vacuum. Joints will weld themselves together, the wood will splinter and break as the gases and liquids inside of it are worked on by the incredible negative pressure of hard vacuum, all sorts of nasty things will happen to a warforged who tries to stay out in space too long.

kpenguin
2007-09-22, 02:30 AM
Here's what NASA has to say (http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html) about humans in space.

tannish2
2007-09-22, 02:59 AM
well. on getting there theres always teleport. or ninjas.

Ted_Stryker
2007-09-22, 03:22 AM
Actually, you do. In order to release internal energy as heat, you need to be in thermal contact with another mass. Since aren't in thermal contact with anything while in a vacuum, the only way to release that internal energy and freeze is to release it kinetically.
You're describing conduction, but that's only one of the three ways through which heat transfer can occur. There's also convection and radiation:

http://theory.uwinnipeg.ca/mod_tech/node74.html

Radiation can occur even if an object that has a finite temperature is surrounded by a perfect vacuum. Also, interstellar space is a hard vacuum but by no means a perfect vacuum, so there is a tiny bit of conduction in that case, but radiation tends to dominate heat transfer in deep space.

It's certainly the case that people will suffocate before they freeze to death if they are exposed to the vacuum of deep space, but a creature that was impervious to suffocation and radiation but susceptible to freezing would eventually freeze in deep space, it would just occur on a considerably longer timescale than human suffocation would occur in such conditions.

Alleine
2007-09-22, 11:58 AM
I probably should have paid more attention in my physics class, *sigh*

I didn't realize there were such detailed descriptions of warforged, all I have is the ECS which isn't that specific.

I think for actually making into space there will be few complications, seeing as generally there are problems with propulsion and, I believe, reaching escape velocity. In DnD the propulsion is almost always constant, and I'd rather not have to go through the process of turning an airship into a shuttle. Reentry will be a bit more bumpy though.

Nerd-o-rama
2007-09-22, 12:22 PM
Hm. Ted_Stryker has a good point. Humans will suffocate, or die of aerembolism, long before the heat radiates out of their bodies, but things that don't have to breathe might need to worry.

Citizen Joe
2007-09-22, 12:34 PM
Yea, cold isn't much of a problem really. Heat can only radiate away, which isn't that fast. Conduction is much faster. So, while immediate radiation of heat would be slow, if you touched a piece of metal that was floating around for a while to cool off, you'd definitely have a cold reaction. Another thing is that liquid water would immediately flash off in a vacuum. Ice can exist, but water can't exist in a liquid form in a vacuum.

Of course, all that is based in reality, not a fantasy simulation.

daggaz
2007-09-22, 12:43 PM
[QUOTE=Zincorium;3230408] and liquids inside of it are worked on by the incredible negative pressure of hard vacuum, [QUOTE]

Its zero pressure, not negative pressure. There is no such thing as negative pressure, unless you delve into the realm of advanced theoretical physics. Science, at least on our scale of things, never "sucks."

daggaz
2007-09-22, 12:45 PM
Actually, you do. In order to release internal energy as heat, you need to be in thermal contact with another mass. Since aren't in thermal contact with anything while in a vacuum, the only way to release that internal energy and freeze is to release it kinetically.

heh. then how, praytell, does the sun heat the earth? Radiation, baby. Radiation.

goat
2007-09-22, 12:46 PM
Space suits are actually cooled rather than heated normally. They're insulated to a level whereby the amount of heat your body generates is more than enough to overheat you after a while. Without one, you will cool down in the shade, but not for a while, just as you'll heat up in the sun, but not that quickly. A warforged might even be able to reflect most of the incident heat by polishing its body plating.

Problems are quickly going to come from the lack of air, and any damp areas of the body. Your eyes will lose moisture quickly, and cool quickly as it evaporates away, they'll be cold and dry, but not permanently damaged if exposure is short. Your mouth and nose will get amazingly cold, could be permanent damage to soft tissue if you're out too long.

In D&D, just don't be a wet skinned, amphibious creature, you'll probably freeze-dry.

kpenguin
2007-09-22, 12:55 PM
heh. then how, praytell, does the sun heat the earth? Radiation, baby. Radiation.

*mutters something about second-rate physics education*

goat
2007-09-22, 12:56 PM
heh. then how, praytell, does the sun heat the earth?

Isn't it obvious?

MAGIC.

Laesin
2007-09-22, 02:42 PM
9000 gp for a necklace of adaptation makes vacuum a perfectly comfortable environment. Without it just use the suffocation rules as it seems that thats what'll kill you quickest. nb suffocation rules don't quite work as holding your breath in vacuum would be disastrous.

kme
2007-09-23, 11:34 AM
Greater teleport has no maximum range.You can greater teleport to any point in space, and that is pretty strange. If some kind of life existed in space wouldn't gods know it?What about outsiders who take interest in material plane, do they just take interest about that particular planet where PCs are born? Or are there outer, elemental and inner planes for every planet?
I know DM can just rule it as he likes but still :smalltongue: .

kjones
2007-09-23, 12:26 PM
First of all, pressure is generally considered as a difference, so "negative pressure" would just mean that you're considering the internal pressure of, say, a person to be zero. Thus, everything lower than that is negative.

As for the heat issue, the thermal systems of space suits are much more concerned with keeping people cool than keeping them warm, especially when in full sunlight. If you don't need to worry about vacuum issues, your next problem will be cooking (if you're in the sun or near some other heat source) or freezing if you're not.

If you look at the equations on this page (http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/cootime.html), you'll see that it would actually take quite a while for a person to lose a life-threatening amount of heat. (Yes, you can approximate a person as a sphere. Physicists do it all the time.) This is because, as mentioned before, there are three methods of heat transfer: conduction, convection, and radiation. Only radiation can occur in a vacuum.

Arbitrarity
2007-09-23, 12:32 PM
Nailed To The Sky
Conjuration [Teleportation]
Spellcraft DC: 62
Components: V, S, XP
Casting Time: 1 standard action
Range: 300 ft.
Target: Creature or object weighing up to 1,000 lb.
Duration: Instantaneous
Saving Throw: Will negates
Spell Resistance: Yes
To Develop: 558,000 gp; 12 days; 22,320 XP. Seeds: foresee (to preview endpoint of teleportation) (DC 17), transport (DC 27). Factors: unwilling target (+4 DC), increase range from touch (+4 DC), 1-action casting time (+20 DC). Mitigating factor: burn 1,000 XP (-10 DC).

Nailed to the sky actually places the target so far from the surface of the world and at such a speed that it keeps missing the surface as it falls back, so it enters an eternal orbit. Unless the target can magically fly or has some other form of non-physical propulsion available, the target is stuck until someone else rescues it. Even if the target can fly, the surface is 2 to 4 hours away, assuming a fly spell, which allows a maximum speed of 720 feet per round while descending. The target may not survive that long. Depending on the world where nailed to the sky is cast, conditions so far from its surface may be deadly. Deleterious effects include scorching heat, cold, and vacuum. Targets subject to these conditions take 2d6 points of damage each from heat or cold and 1d4 points of damage from the vacuum each round. The target immediately begins to suffocate.

XP Cost
1,000 XP.



The "RAW" vacuum. Rather pathetic, really.

Dervag
2007-09-23, 12:40 PM
The only thing about livewood is it is still alive. Meaning there is still liquid in it that will evaporate. It doesn't breathe.Liquids will come out of the woodwork and evaporate over time, causing the livewood to dry up and die eventually, but the time scale of 'eventually' will be considerably longer than it would for the human body, which has this big spongy bag full of gas built into its ribcage. So a warforged could last longer than a human being in a vacuum, since they don't have any components that would explode in the absence of air pressure or organs that immediately cease to perform a vital function without air pressure.

I'd guess that for a warforged, 'eventually' would be measured in minutes or hours.


You definitely need moving molecules to freeze to death, if they aren't moving then they have no energy and are already "frozen". A construct is going to last longer in space because they don't rely on the weak flesh that meatbags use. Metal, for the most part, will take a lot less damage from exposure to vaccum than flesh will, mostly because metal can't die. Things are a tad different for warforged though.It's more complicated than that. Flesh suffers in vacuum because it contains dissolved gases in the blood and because creatures made of flesh have lungs that can't contain air against a total lack of outside air pressure. I can imagine 'flesh' organisms capable of surviving in a vacuum for much longer than human beings without being intrinsically more resistant to other kinds of physical damage than human beings.


I think for actually making into space there will be few complications, seeing as generally there are problems with propulsion and, I believe, reaching escape velocity. In DnD the propulsion is almost always constant, and I'd rather not have to go through the process of turning an airship into a shuttle. Reentry will be a bit more bumpy though.Reentry doesn't have to be bumpy for a ship capable of hovering against gravity for extended periods. The reason space shuttles and capsules get superheated on reentry is that they have to glide into the atmosphere, starting at orbital speeds. At orbital speeds air resistance is hellacious and you get a lot of drag and heating from drag.

If you can use constant acceleration to lift off and touch down from a planet, you don't need to have a super-high speed at any point in your trajectory near the planet (though, of course, you do need super-high speed to fly between planets).


Its zero pressure, not negative pressure. There is no such thing as negative pressure, unless you delve into the realm of advanced theoretical physics. Science, at least on our scale of things, never "sucks."You're oversimplifying. It is absolutely true that on the surface of the body, from the perspective of the inside of the body, your skin would be at negative pressure in a vacuum. This is because the body is designed to exert a positive pressure on its surface; it is 'inflated'.

A net positive pressure from the point of view of one side and a net negative pressure from the point of view of the other side are (literally) two sides of the same coin.