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Post by oprean on Nov 7, 2016 19:59:27 GMT
True, but compression suits aren't so bad. My assumption is that hypersonic shock and the resulting firestorm are probably going to accomplish what decompression probably isn't. You are right, but the shock wave strength depends on the object size as well as the speed, but let's compare a 3 g round at 1.5 km/s and a 10 kg round traveling at 5 km/s, one makes a loud ballistic crack, and the other will straight up kill you if it goes past you, where is the cut off point?
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Post by argonbalt on Nov 11, 2016 6:04:04 GMT
True, but compression suits aren't so bad. My assumption is that hypersonic shock and the resulting firestorm are probably going to accomplish what decompression probably isn't. You are right, but the shock wave strength depends on the object size as well as the speed, but let's compare a 3 g round at 1.5 km/s and a 10 kg round traveling at 5 km/s, one makes a loud ballistic crack, and the other will straight up kill you if it goes past you, where is the cut off point? Uh why have a cut off point? Indeed why have any atmosphere at all? Besides ease of environmental conditions, decompressing a majority of crew quarters is the ideally correct thing. Think of the advantages: -no firestorm -no shock waves -no absolute environmental loss from a single shot -Individual space suits permit individual survivability to skyrocket. while granting additional radiation and chemical benefits -Furthermore compromised sections could still operate even in catastrophic conditions for at least the duration of their oxygen supply Instead of shot-to-puncture, it should instead be based on a majority of the Hab section being punctured or melted, upwards of at least 30% i think? If that takes out one full third of the three shift crew standard or punctures the hab nicely. And no the comparison of Full EVA gear is not correct to diving suits. Diving Suits have to be ludicrously sturdy upwards of several atmospheres. www.youtube.com/watch?v=O4RLOo6bchU
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Post by oprean on Nov 11, 2016 19:37:37 GMT
You are right, but the shock wave strength depends on the object size as well as the speed, but let's compare a 3 g round at 1.5 km/s and a 10 kg round traveling at 5 km/s, one makes a loud ballistic crack, and the other will straight up kill you if it goes past you, where is the cut off point? Uh why have a cut off point? Indeed why have any atmosphere at all? Besides ease of environmental conditions, decompressing a majority of crew quarters is the ideally correct thing. Think of the advantages: -no firestorm -no shock waves -no absolute environmental loss from a single shot -Individual space suits permit individual survivability to skyrocket. while granting additional radiation and chemical benefits -Furthermore compromised sections could still operate even in catastrophic conditions for at least the duration of their oxygen supply Instead of shot-to-puncture, it should instead be based on a majority of the Hab section being punctured or melted, upwards of at least 30% i think? If that takes out one full third of the three shift crew standard or punctures the hab nicely. And no the comparison of Full EVA gear is not correct to diving suits. Diving Suits have to be ludicrously sturdy upwards of several atmospheres. www.youtube.com/watch?v=O4RLOo6bchUI think the problem stems from modules not having HP, their integrity is either "operational" or if something penetrates the outer shell, "unoperational" if qswitched ever decides to implement a HP system in the future, we'll see how things turn out.
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Post by targetx on Nov 11, 2016 20:56:22 GMT
If you mouse over modules that have been hit, you'll sometimes see the DAMAGED status. The modules, if powered are still operational, but operate at reduced capacity
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Post by n2maniac on Nov 12, 2016 21:28:18 GMT
Here's another thing: Why wouldn't the crew (knowing that they're going into combat) put on space suits so that they can survive any depressurization event and (potentially) even keep fighting? The same reason submarine crews don't work while on diving suits: they're too cumbersome to use while keeping combat effectiveness. Yes. Current military doctrine has examined this possibility and rejected individual protection for the all-or-nothing approach due to combat effectiveness. CBRN (chemical biological radiological nuclear) protection follows the same lines.
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Post by argonbalt on Nov 13, 2016 0:13:00 GMT
Once again this fails to recognise the vast difference in design and and practicality of the two situations. Modern Nuclear submarines have an average crush depth of 490m. The ocean adds one full ATM of pressure per 10.3 cubic metres of seawater right? So that's an insane 19 ATM's. SO a diving suit is reasonably not practical inside at those depths as it needs to withstand a ludicrous amount of pressure should a breach occur right?
But a space craft need only ever maintain and INTERNAL pressure of 0-1. SO in a breech a space suit need maintain a similar 1 ATM for each person. Arguably the only main hurdles is what will be useful for air cleaning and for how long. But in terms of raw issues the biggest additional bulking up item is the radiation padding needed for the space suits.
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Post by jonen on Nov 13, 2016 1:10:07 GMT
Once again this fails to recognise the vast difference in design and and practicality of the two situations. Modern Nuclear submarines have an average crush depth of 490m. The ocean adds one full ATM of pressure per 10.3 cubic metres of seawater right? So that's an insane 19 ATM's. SO a diving suit is reasonably not practical inside at those depths as it needs to withstand a ludicrous amount of pressure should a breach occur right? But a space craft need only ever maintain and INTERNAL pressure of 0-1. SO in a breech a space suit need maintain a similar 1 ATM for each person. Arguably the only main hurdles is what will be useful for air cleaning and for how long. But in terms of raw issues the biggest additional bulking up item is the radiation padding needed for the space suits. Hm. Rambling stream of consciousness follows. As I understand it, a submarine crew at battle stations are usually in their shirt sleeves (or work uniforms). Excepting, possibly, damage control crews (and particularly firefighters). The crew of a surface navy ship tend to wear their basic duty uniforms, possibly adding flame retardant hoods and in some cases body armor and helmets - depending on situation. And DC crew probably a bit more than that. The crew of a bomber are in flight suits, have masks and helmets. ... Reasonably, the environment in the crew module would be a shirtsleeve environment most of the time (or at least as shirtsleeve as you get on a spacecraft - jumpsuit?) - you live and work in that minimal volume with a bunch of other people for a long time. Engagements can usually be seen coming, so you do have time to suit up before combat - though for dealing with accidents you probably want to have something you can throw on quickly in case of fire or depressurization or whatever. Reasonably speaking, when you go into battlestations, you suit up, strap down at your station and stay that way until the all clear - the only people that should be moving about inside the crew module during action would probably be DC crew if the hab module suffers light damage. Strapping down is mostly because the ship will be thrusting and maneuvering - and kinetics impacting are going to make things shake and shudder a bit. Having stuff floating around in the crew module prior to action is asking for trouble (and everyone knows the military loves to have things nice and clean and in their proper order). So probably - even if the crew doesn't suit up in proper EVA suits, they go into battle in pressure suits that'll keep them alive - if only for a limited time - in a vacuum. Maybe their suits won't let them work very well in a vacuum, but they only need to keep them alive until the DC techs (in an armored, possibly EVA rated space suit?) can patch the holes and restore a bit of pressure. Or if the DC tech has to dump pressure to put out fires and vent fumes. Probably have most of the actual life support in the - seats? berths? chairs? beds? - the crew strap into during action, hook up to the air and water supply of that specific crew-station, and it can feed air from the module, or cut to an individual supply, as dictated by the damage. Kind of like an ejection seat on an aircraft, only it's not designed to eject, since there is no more safety to be had outside than in. Worst comes to worst, the crewman can strap into their crew-station and pull down and zip up a pressure bubble over it. If the crew wear temperature controlled undersuits (water cooling, maybe) and some insulating blankets to pull over themselves, they can probably deal with temperature shifts (though lasers burning into the crew module is probably a bit much). For radiation... If they can wrap themselves in something like a sleeping bag that'll fill up with water to provide individual radiation shielding to add to whatever is provided by (whatever's left of) the ships armor, hull, whatever structure is between them and the radiation source and and the skin of the module itself you've probably done about as well as you can... You know, the game lacks the option to put modules inside modules - now I kind of wanna put a crew module inside a propellant tank - and have the engines tap that propellant tank last - for radiation shielding that can also be used as propellant. ... Hell, the crew at action stations (excepting DC - who need to be able to get up and mobile) can be basically in a pressurized sleeping bag with arms and a helmet, more or less, strapped into their "seats" and hooked up into the life support, but with enough supplies in a pack attached to their bag that a DC tech can unhook them from the seat and shift them to someplace more convenient if necessary. Hm. Helmet mounted displays might mean they don't really need screens (though I expect those would exist for day to day use), and if they have control surfaces inside the sleeping bag they don't even need to have arms on the suit... Though, probably have something like arms on the suit anyway - maybe simple waldoes operated from inside the pressure bag? EDIT: Hell, does the thing even need a helmet? Maybe just make the bag (or parts of it) transparent. Probably advisable to have a crash helmet on inside the pressure bag, and possibly a back/neckbrace, depending on how much force you're expecting to be imparted by enemy fire...
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Post by argonbalt on Nov 13, 2016 2:36:02 GMT
that is some really good elaboration. here are some sketches based on my thoughts and the stuff you mentioned. Attachment Deleted
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Post by jonen on Nov 13, 2016 3:19:52 GMT
Hm, astronauts wear diapers on EVA. Probably a good bet for crew in combat as well. Legs would probably be held fairly tight together to save bit of volume - good idea with pedals, though - having some control inputs by the feet may be useful for some roles. One of the near future thingamajigs that've been thought up and been on the way for a while is a kind of mail mesh undersuit for soldiers that monitors vital signs and can constrict to help deal with bleeding. Possibly overkill if the bag doesn't also have something to deal with holes causing pressure loss in the bag. Probably best to keep the number of connectors (weak points in the bag) low - bundle up cables in and out. And a single fairly big airlock that doubles as the way to crawl into and out of the bag (it won't function as an airlock for that without attaching/extending a tube, but you can hook two bags together to crawl between them - or just get access - so if someone takes a hit, patch the holes in the bag and hook it up to the Doctors, and you can start doing surgery, or what have you - and it can function like an airlock for getting small objects in and out. For the DC crew I was thinking something like the spacesuits in the Planetes anime - armored, with cameras and screens (and a faceplate you can raise if your cameras go on the fritz or get blocked). Hooked into a mobility rig if there's space. OTOH, since the DC crew may need to move around inside the crew module for firefighting (also part of their job), maybe something like what the DC crew of the Bellarmine used - more or less skin tight (if armored). ... Hm. When the ship is under thrust, there would be a clearly defined down, so it may make sense to place all the crews battlestations on the floor - yes, you can use every surface as a workstation in freefall, but a combat space craft have to be able to undergo unplanned acceleration with little warning, so probably no storage spaces in the ceiling if you can avoid it, even if the thrusters only manage microgees. For ships that are intended mostly for broadside combat with a specific facing, and more capable maneuver thrusters in the vertical things get complex... But otherwise the standard layout for a combat spacecraft crew module would probably be all crew action stations on the floor and screens and displays in the ceiling, storage compartments mostly in the walls and floor. It may make sense for the crew to sleep in their action stations - with digital interfaces you can swap instrumentation and controls fairly easily, so no need to shuffle crew around when the shifts end - crew stepping on watch sign in and standby, handover is done, crew going off shift log off. Crew would get up and about for exercise and other duties. EDIT: While most of the designs for crewed spacecraft in the game rarely push more than 3 gees (well, my designs, and honestly, the three G design tended to run itself out of deltaV too fast), so it's probably not a necessary constraint - having the crew sitting/lying with their arms above them and legs elevated may not be the best solution?
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Post by apophys on Nov 13, 2016 14:06:37 GMT
I'd think the optimum solution for low mass and improved survivability would be a skin-tight compression suit and a strapped-on mask providing air to the nose and mouth. Losing pressure to the cabin would be mostly ignorable in the short term, as long as the personal air supply remains pressurized.
The chair could be inside a gimbal to ensure that acceleration in any direction is always downward to the crewmember. Combined with a compression suit and training, that could allow survival of up to 20 g's of acceleration. I'm thinking of the ship getting spun by nuke strikes or propellant blowouts.
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Post by beta on Nov 13, 2016 14:45:42 GMT
Modern surface naval crews will generally wear flash suits during general quarters. Lots of flash burns casualties for ships that have been hit by ASMs. The sheer destruction that can be caused by a hypervelocity projectile flying through a pressurized vessel would be more than enough for me to consider adding an extra 1 ton per 10 crew to support EVA suits so you can get rid of that casualty and damage producing atmosphere for the brief moments of combat. You can store compressed atmosphere for quite low mass and volume costs, especially if it is only for brief periods of time. Power is also not a major concern, as it is quite abundant on the majority of spacecraft designs.
Further, the concept of firefighting in a spacecraft is a bit daft. Another excellent reason to be in a suit. For some reason, you are in battle with an atmosphere still and there is a fire. Vent atmosphere. No more fire. If you have a self-oxidizing fire, you should strongly reconsider your spacecraft construction materials.
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Post by jonen on Nov 13, 2016 16:35:16 GMT
I'd think the optimum solution for low mass and improved survivability would be a skin-tight compression suit and a strapped-on mask providing air to the nose and mouth. Losing pressure to the cabin would be mostly ignorable in the short term, as long as the personal air supply remains pressurized. The chair could be inside a gimbal to ensure that acceleration in any direction is always downward to the crewmember. Combined with a compression suit and training, that could allow survival of up to 20 g's of acceleration. I'm thinking of the ship getting spun by nuke strikes or propellant blowouts. Chair gimbals would add a lot of mass to the crew module, and take up a lot of the internal volume, which makes it harder to move around in any conditions (and particularly for DC crew: all those moving parts under variable gravity - that's bad things waiting to happen). Maybe for smaller ships that may actually be likely to happen (and presumably, the craft has short endurance so a cramped crew compartment can be endured), but for larger craft you'll probably have to get by with padding and G-suits (so the undersuit have multi-functionality), and maybe a bit of limited gimbals.
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