As its a spacegame there is considerable chance that you'll need the rules for what happens if someone enters vacuum unprotected. Unfortunately the rules in DH are hollywood fiction overkill when compared to real effects of vacuum. Acooridng to DH rules you survive rounds equal to toughness bonus unharmed and after that start to take 1d10+3X (automatic) plus 1d10E (toughness save to negate) each round . This means an everage human exposed to vacuum would survive approximately 10 to 15 seconds unharmed and then literally deepfreezexplode to death in 5 to 10 seconds.

However, real life science (tested by several scientist over the last 300 years with live animals and, in case of nazis, live humans) says following:

Humans and animals exposed to vacuum will lose consciousness after a few seconds and die of hypoxia within minutes.

Rapid evaporative cooling of the skin will create frost, particularly in the mouth, but this is not a significant hazard.

Rapid and complete recovery is normal for exposures shorter than 90 seconds. Limbs may be exposed for much longer if breathing is not impaired.

Doesn't sound exactly like 1d10+3X and 1d10E per round, does it? Especially interesting is the fact that for the cause of death is hypoxia, which is exactly same as the cause of death in suffocation except in the case of vacuum the hypoxia develops about twice as fast. On the dreaded "oh noes, you will explode with decompression" the actual scientific data says following:

Blood and other body fluids do boil when their pressure drops below 6.3 kPa, (47 torr) the vapour pressure of water at body temperature.[3] This condition is called ebullism. The steam may bloat the body to twice its normal size and slow circulation, but tissues are elastic and porous enough to prevent rupture. Ebullism is slowed by the pressure containment of blood vessels, so some blood remains liquid.

Rapid decompression can be much more dangerous than vacuum exposure itself. Even if the victim does not hold his breath, venting through the windpipe may be too slow to prevent the fatal rupture of the delicate alveoli of the lungs. Eardrums and sinuses may be ruptured by rapid decompression, soft tissues may bruise and seep blood, and the stress of shock will accelerate oxygen consumption leading to hypoxia. Injuries caused by rapid decompression are called barotrauma. A pressure drop as small as 13 kPa (100 torr), which produces no symptoms if it is gradual, may be fatal if occurs suddenly.

House Rules for Rapid Decompression and Vacuuum

Rapid Decompression

I1d10+3X damage per round for rapid decompression for up to 3 rounds after which you are exposed to vacuum. In rapid decompression scenarios the time of exposure is relative to the amount of time you spend in the way of the air rushing out. If you are in a small, close room or airlock when the door (or hole as it may be) opens to vacuum, you'll only suffer 1 round of rapid decompression damage. In bigger space it might be 2 or 3 rounds. After 3 round your body is already depressurized and there is no further rapid decompression damage.

Vacuum

In vacuum a person will start suffocating at double rate if not wearing a breathing apparatus. In addition anyone exposed to vacuum will take 1d10+3X damage/minute.

from france

this sound good and i apreciate the effort but... i alaways prefered the more cinematic version. homwever as master that sometimes has professional rules addict i can use it. thanks

A question from someone who isn´t in the know:

Why is it making a difference how big the room is you are in?

Thank you!

Gregorius21778 said:

Rapid decompression damage simulates the pressure dropping while huge volumes of air rush to the vacuum outside. As noted the vacuum itself isn't the thing that hurts... its the rushing air. With same size of hole in the hull smaller room will have less air and thus pressure drops to zero faster. A larger room has more air so you get hit by that "blast of rushing air" for longer time before the pressure is gone. The rules I propose for this are not 100% scientifically accurate, but I'd rather keep the system simple.

@8 spider: I know what you mean, but then I thought that DH is essentially a horror genre game and lets face it, hollywood style of "you enter vacuum, your head explodes" isn't nearly as horrifying as the concept of slow, agonizing death of drowning in your own bursted lungs or the permanent damage you might suffer to eyes, ears and brain even if you do get rescued in time...

Okay, got it. "No pressure out side = something the body can get along with under certain circumstance // overextrem windchill = that hurts!"

Capillaries burst in your ears, eyes and nose. Bloodvessels swell. Blood seeping through the pores in your skin. Lungs burst if you have too much air inside of them. Moisture flash freezing.

No head explosion like in the movie Total Recall when you get outside normal airpressure.

You can say not so nice way to die. Any way you watch that your screwed

Only thing that would propably kill you quite instantly would be that you get sucked into the hole just like in the Alien: Resurrection

This is what happens to your blood in vacuum

But you can say these rules are little bit more practical than those in DH core.

Humans don't rupture, nor do they freeze in space (at least not instantly). The pressure difference between a pressurised space ship and a vacuum is only one atmosphere, which is the equivalent of coming up from 10 metres under the ocean.

Vacuum has no temperature or pressure. Water on your skin will evapourate into gas, but your skin itself acts as a pressure suit applying pressure against your blood vessels. Air will be pulled out of your lungs and might damage some alveoli, but your lungs won't freeze or explode.

imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html

Nasa says as much and this website explains why your blood won't boil in your veins:

www.geoffreylandis.com/vacuum.html

They have been developing elastic space suits for a while now. Suits that produce mechanical pressure to simulate a 1 atm environment.

You don't freeze in space instantly because space doesn't have a temperature. If you aren't in line of sight of the local star you will gradually cool down through heat radiation (the spontaneous emitence of infrared radiation from your body atoms over time). Without an atmosphere you cannot conduct heat way from the body - that is, without molecules surrounding you to run into your body, absorb the radiation and take it away, you won't cool down quickly.

If you touched an asteroid though, your hand would freeze quickly followed by your arm and body as the heat is conducted out into the rock (which will be close to absolute zero).

If you are in direct line of the sun you will burn depending on how far away you are (in orbit around the earth it's hot enough to kill you).

Hellebore

I've always been a fan of gory decompression followed by the remains shriveling into a grey husk which acts as a silent and eternal monument to an agonizing death. It really reinforces the idea that if someone opens the window of the ship, all the aether will rush in and everyone will drown horribly.