The Russian cosmonaut that EVAd had to puncture the suit to fit back in the airlock if I remember correctly

OnlyForNow said:

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I'm thinking of the suit having a positive outward pressure keeping it "stuffed" full of air and astronaut.

What you're saying is that the pressure of space is decreasing the potential volume of the space suit by exerting outside forces acting on the malleable suit.

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No. As the astronaut moves, the suit changes shape with his movement. The change in shape comes with a resulting change in volume and pressure within the suit.


PV=nRT

n is the constant mass of air inside the suit. R is the gas constant. As the suit changes shape and volume with the astronaut's movement, P or T must change accordingly, both of which require work.




ETA
There is no pressure in space because it is a vacuum. The air in the suit exerts an outward force on the suit, which is counteracted by the tensile strength of the suit's material and it pushing back on the air. Essentially, it's a giant balloon. However, different permutations of the suit's shape have different volumes. If you inflate the suit to its optimal surface area to volume ratio, like that of an inflated ball or balloon, any change to the shape is now suboptimal, like trying to press down on a ball or balloon and flatten it. Same container, different internal volumes. So if an astronaut is inside the suit and it is in that optimal shape, fully inflated, moving his leg or his arm or even his fingers changes the volume of the suit. That change is experienced as a difficulty to move because it is compressing the air within the suit.

If the volume were constant, changes in shape would require changes in surface area, meaning a stretching of the suit. This is like squeezing a balloon and stretching it really thin. In the astronaut's case, he'd be stretching stretching spacesuit material, which isn't going to happen.

OnlyForNow said:

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That has nothing to do with volume though.

And I'm splitting hairs but that's my point, the volume doesn't change. Being physically difficult to move has nothing to do with volume. The volume of a space suit is "X" Liters, it doesn't change if it is working correctly in space or on earth. Pressure on the suit can certainly make it impossible to move, but it doesn't increase or decrease its volume.

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Your understanding of suits is wrong. Suits do have significant volume changes. When doing suit leak checks we make the crew stay still because movements can increase or decrease the volume of the suit and alter the pressures we're monitoring.

One way to consider it is to look at a sphere. From the perspective of surface to volume ratios, it is the most efficient shape for containing any volume. Therefore pushing in the sides of the sphere from the inside or outside must result in a less efficient shape. For a fixed amount of suit material, any changes in shape away from the ideal will result in a decrease in volume and corresponding increase in pressure.

Similar scenario with cylinders being the most efficient linear shape to contain a given volume. Start curving that cylinder like a macaroni noodle and the efficiency drops, volume decreases and pressure goes up. And what are a suit's arms, legs, fingers, and abdomen sections if not approximations of cylinders?

EMU gloves used to be sewn with straight fingers and astronauts would get extremely fatigued just holding tools or grabbing hand holds. Several even lost fingernails during their EVAs.

The Russian's Orlan gloves on the other hand were stitched with a nominally closed fabric pattern. This gave their gloves macaroni shaped fingers. It was much easier to grip items as a result because the increased stress was in the fabric and not the cosmonauts fingers.

This was an improvement over the early EMU gloves and is one of the technologies that permitted cosmonauts to use arguably safer 5.8 psia space suits. NASA instead traded the added DCS risks and increased prebreathe time for added mobility and better fatigue management.

ETA: Looks like the BQ above me used a similar analogy. I had prepared balloon animal pictures for illustration but opted not to include them. Also corrected numerous typos.

Nm. Hit quote instead of edit.

ABATTBQ11 said:

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OnlyForNow said:

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I'm thinking of the suit having a positive outward pressure keeping it "stuffed" full of air and astronaut.

What you're saying is that the pressure of space is decreasing the potential volume of the space suit by exerting outside forces acting on the malleable suit.

---

No. As the astronaut moves, the suit changes shape with his movement. The change in shape comes with a resulting change in volume and pressure within the suit.


PV=nRT

n is the constant mass of air inside the suit. R is the gas constant. As the suit changes shape and volume with the astronaut's movement, P or T must change accordingly, both of which require work.




ETA
There is no pressure in space because it is a vacuum. The air in the suit exerts an outward force on the suit, which is counteracted by the tensile strength of the suit's material and it pushing back on the air. Essentially, it's a giant balloon. However, different permutations of the suit's shape have different volumes. If you inflate the suit to its optimal surface area to volume ratio, like that of an inflated ball or balloon, any change to the shape is now suboptimal, like trying to press down on a ball or balloon and flatten it. Same container, different internal volumes. So if an astronaut is inside the suit and it is in that optimal shape, fully inflated, moving his leg or his arm or even his fingers changes the volume of the suit. That change is experienced as a difficulty to move because it is compressing the air within the suit.

If the volume were constant, changes in shape would require changes in surface area, meaning a stretching of the suit. This is like squeezing a balloon and stretching it really thin. In the astronaut's case, he'd be stretching stretching spacesuit material, which isn't going to happen.

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Why do we have to have pressurized suits? Seems pressurizing the ass and head would do fine. So if you can isolate those, what is the worry? You could operate in a vacuum with no concern for your extremities other than thermal loss/gain. Now the suit DOES have to be airtight, however not pressurized.

Because reasons

For one, it would need to be really tight and would be hard to get into.

For two, debris. A skin tight suit would lightly offer vet little protection on an EVA.

For three, you need temperature regulation and other things to keep the astronaut safe.

There are others, but long story short it's because it's the best option.

10thYrSr said:

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ABATTBQ11 said:

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OnlyForNow said:

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I'm thinking of the suit having a positive outward pressure keeping it "stuffed" full of air and astronaut.

What you're saying is that the pressure of space is decreasing the potential volume of the space suit by exerting outside forces acting on the malleable suit.

---

No. As the astronaut moves, the suit changes shape with his movement. The change in shape comes with a resulting change in volume and pressure within the suit.


PV=nRT

n is the constant mass of air inside the suit. R is the gas constant. As the suit changes shape and volume with the astronaut's movement, P or T must change accordingly, both of which require work.




ETA
There is no pressure in space because it is a vacuum. The air in the suit exerts an outward force on the suit, which is counteracted by the tensile strength of the suit's material and it pushing back on the air. Essentially, it's a giant balloon. However, different permutations of the suit's shape have different volumes. If you inflate the suit to its optimal surface area to volume ratio, like that of an inflated ball or balloon, any change to the shape is now suboptimal, like trying to press down on a ball or balloon and flatten it. Same container, different internal volumes. So if an astronaut is inside the suit and it is in that optimal shape, fully inflated, moving his leg or his arm or even his fingers changes the volume of the suit. That change is experienced as a difficulty to move because it is compressing the air within the suit.

If the volume were constant, changes in shape would require changes in surface area, meaning a stretching of the suit. This is like squeezing a balloon and stretching it really thin. In the astronaut's case, he'd be stretching stretching spacesuit material, which isn't going to happen.

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Why do we have to have pressurized suits? Seems pressurizing the ass and head would do fine. So if you can isolate those, what is the worry? You could operate in a vacuum with no concern for your extremities other than thermal loss/gain. Now the suit DOES have to be airtight, however not pressurized.

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Why are you trying to kill astronauts? With no pressure on your body and just a pressure mask/helmet you're going to wreck your lungs in short order.

To stay normoxic on 100% O2, you will need to be breathing gas at about 3psia. At as little as about 1.5 psi delta pressure you would start seeing pulmonary barotrauma as overdistension of your alveolar sacs starts tearing alveolar tissues. Then there are gas bubbles being forced through your capillary tissues.

Now that you're suffering from a pulmonary embolism, blood clots will start forming in your lung's capillary beds and death will be knocking on your door soon enough. Even if all this clotting doesn't kill you, this lung trauma will will introduce gas into your body which will collapse your lungs.

But the gas in your body will be looking for an exit and will keep moving to other parts of your body. When it's under your skin it's called subcutaneous emphysema. Even when the pressure of the gas is equal to ambient pressures, like under your helmet, this gas will start still move to your neck and face producing grotesque swelling. This could become even more pronounced in areas of your body not protected by a pressure suit. But luckily you're already dead from the pulmonary embolism and won't have to suffer the indignity of seeing your body swollen and bloated like a corpse pulled from the east river.

Then there are other effects like how the vapor pressure of water at 98F is 47mmHg so any sweat you produce while your skin is at vacuum would boil in your sweat glands. But 47mmHg isn't likely to cause the same tissue damage that would be seen in the alveolar sacs and May not be a huge concern given the acute barotrauma you're experiencing.

I think you could do it, but the suit would need to be what exerts pressure on the person through contraction. Think like a wetsuit, but tighter.

lb3 said:

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[
One way to consider it is to look at a sphere. From the perspective of surface to volume ratios, it is the most efficient shape for containing any volume. Therefore pushing in the sides of the sphere from the inside or outside must result in a less efficient shape. For a fixed amount of suit material, any changes in shape away from the ideal will result in a decrease in volume and corresponding increase in pressure.

s.

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This is where I get lost.

If you take a basketball and fill it with matter, that matter has a very specific volume. If you then compress the basketball, the volume of the matter inside isn't changing. Sure the shape of the matter changes, the vessel dimensions change, and the ability of the matter to move changes, but you can't get rid of the matter that's inside the vessel without either making the vessel not airtight or breaking a law of thermodynamics.

Human body's can be compressed, water can't. So if you filled a spacesuit COMPLETELY with water it has a volume. No mater what you do to that suit unless you puncture it, the volume of water in the suit won't change. Twisting a sleeve will make it impossible for water to travel from the hand to the body of the suit, but the volume of water didn't change.

Stupid wrong emoji. This is very interesting to me as I obviously don't know anything about it!

ABATTBQ11 said:

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I think you could do it, but the suit would need to be what exerts pressure on the person through contraction. Think like a wetsuit, but tighter.

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That would be fine. it would need to be highly elastic.

I thought he was just suggesting no compression anywhere and just a pressurized mask and a plug up the bum.

I haven't read the entire thread, but remember that mass is conserved, not density. In engineering we assume substances to be incompressible to make our life easier, but in truth everything can be squeezed if there is enough force.

Edit - Nevermind, I see now that we are talking about a bikini spacesuit and turning a human body into a pressure vessel.

Heh

OnlyForNow said:

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lb3 said:

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One way to consider it is to look at a sphere. From the perspective of surface to volume ratios, it is the most efficient shape for containing any volume. Therefore pushing in the sides of the sphere from the inside or outside must result in a less efficient shape. For a fixed amount of suit material, any changes in shape away from the ideal will result in a decrease in volume and corresponding increase in pressure.

s.

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This is where I get lost.

If you take a basketball and fill it with matter, that matter has a very specific volume. If you then compress the basketball, the volume of the matter inside isn't changing. Sure the shape of the matter changes, the vessel dimensions change, and the ability of the matter to move changes, but you can't get rid of the matter that's inside the vessel without either making the vessel not airtight or breaking a law of thermodynamics.

Human body's can be compressed, water can't. So if you filled a spacesuit COMPLETELY with water it has a volume. No mater what you do to that suit unless you puncture it, the volume of water in the suit won't change. Twisting a sleeve will make it impossible for water to travel from the hand to the body of the suit, but the volume of water didn't change.

Stupid wrong emoji. This is very interesting to me as I obviously don't know anything about it!

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You're mistaking volume for mass.

Volume is just length x width x height and a measure of space. If you compress the basketball, you've changed the amount of space inside and changed the volume.

Density=mass/volume

Outside of radioactive decay, mass is conserved, so density and volume change proportionally. If you compress the basketball, the mass of the air is the same, but it has a lower volume and higher density. You've just compressed it.

Same amount of mass in a smaller space



ETA Also, consider if I use a vacuum pump to move all of the air from a perfectly sealed shipping container to a 55 gallon drum that somehow didn't explode. It's the same amount of air, but in a much smaller space. The volume of the container has changed, but the mass of the contents it's constant.

ETA2 Or consider a 1 liter bottle filled with air at sea level. If I hook it up to an air compressor and pressurize it, the volume of the bottle remains 1 liter, though there is obviously more air in the same volume. You have 1 liter if air, but you have a larger mass of air because it is more dense and under pressure.

lb3 said:

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ABATTBQ11 said:

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I think you could do it, but the suit would need to be what exerts pressure on the person through contraction. Think like a wetsuit, but tighter.

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That would be fine. it would need to be highly elastic.

I thought he was just suggesting no compression anywhere and just a pressurized mask and a plug up the bum.

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The crotchular region would be an interesting fit for sure

OnlyForNow said:

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lb3 said:

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[
One way to consider it is to look at a sphere. From the perspective of surface to volume ratios, it is the most efficient shape for containing any volume. Therefore pushing in the sides of the sphere from the inside or outside must result in a less efficient shape. For a fixed amount of suit material, any changes in shape away from the ideal will result in a decrease in volume and corresponding increase in pressure.

s.

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This is where I get lost.

If you take a basketball and fill it with matter, that matter has a very specific volume. If you then compress the basketball, the volume of the matter inside isn't changing. Sure the shape of the matter changes, the vessel dimensions change, and the ability of the matter to move changes, but you can't get rid of the matter that's inside the vessel without either making the vessel not airtight or breaking a law of thermodynamics.

Human body's can be compressed, water can't. So if you filled a spacesuit COMPLETELY with water it has a volume. No mater what you do to that suit unless you puncture it, the volume of water in the suit won't change. Twisting a sleeve will make it impossible for water to travel from the hand to the body of the suit, but the volume of water didn't change.

Stupid wrong emoji. This is very interesting to me as I obviously don't know anything about it!

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You are mixing the volume the shape has with the volume of material inside the shape. And materials are compressible, even water. It's just a matter of how much pressure you are willing to exert or how much work you are willing to do to change its temperature.

If it was Gumby in the suit instead of a human some of these solutions could work.

Another issue with the scuba suit concept is that your blood pressure is only about 2psia above ambient so you wouldn't be able to put on a 3.5 psi compression garment at normobaric pressure without cutting off your blood flow. To solve this you would need to don multiple layers with each layer added in succession as you decrease the pressure in your airlock. It would be extremely complicated and any uncompressed tissues (like between your toes etc) would experience edema.

Yeah I don't think it would ever actually work, but in theory it's possible. Maybe if you had some kind of shrink wrap concept where you get in the suit and then shrink it to your body as outside pressure drops.

ABATTBQ11 said:

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Yeah I don't think it would ever actually work, but in theory it's possible. Maybe if you had some kind of shrink wrap concept where you get in the suit and then shrink it to your body as outside pressure drops.

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I would love for nasa to give me a few hundred grand for a research project with the promise of $20m to build a prototype if the research suggests it were feasible.

I'll give you tree fiddy

Here me out… Kerbel Space Suit Program, where you design a suit and see if they explode.

Once again, this thread delivers.

ABATTBQ11 said:

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Yeah I don't think it would ever actually work, but in theory it's possible. Maybe if you had some kind of shrink wrap concept where you get in the suit and then shrink it to your body as outside pressure drops.

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A couple of characters try to fasten homemade suits like this in desperation on the show For All Mankind.

double aught said:

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ABATTBQ11 said:

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Yeah I don't think it would ever actually work, but in theory it's possible. Maybe if you had some kind of shrink wrap concept where you get in the suit and then shrink it to your body as outside pressure drops.

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A couple of characters try to fasten homemade suits like this in desperation on the show For All Mankind.

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And according to space encyclopedia Scott Manley it's fairly accurate. Apparently they kinda over-dramatized how quickly it'd have the effects shown in the show, but didn't stray too far from reality.

SpaceX just got 10 more crew launches to ISS, which means NASA will not buy anymore starliner flights before 2030 if it keeps the two launch per year schedule....

Make me wonder if we will ever see a Vulcan/starliner combo., or if they'll just launch out the Atlas backlog.

There's a launch this morning at 8 am cst? Is it televised?

All of the US launches are televised, in general, via YouTube etc. Some places try to track the feeds but the best thing to do is to check twitter/YouTube within 10 minutes of launch, imho. For SpaceX their streams are a good idea as they are the only ones with the landing video live/on rocket cameras/telemetry etc.

https://youtube.com/c/SpaceX

Some cool slides in this!

Starlink 2.0 sats deploying from Starship Pez Dispenser.

Photo of Raptor 2 engines during installation on Booster 7.

What Starfactory will look like at Starbase (replacing the production tents).

Roberts Road Starship Factory in Florida. https://t.co/JySZMAnD5Q pic.twitter.com/LjFLdaGCzT

— Chris Bergin - NSF (@NASASpaceflight) June 5, 2022

The pez dispenser really does have a Star Wars feel about the video/animation.

Best news out of everything:

Maybe we should make an actual Starship model that dispenses pez for our merch store

— Elon Musk (@elonmusk) June 5, 2022

Decay said:

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Best news out of everything:

Maybe we should make an actual Starship model that dispenses pez for our merch store

— Elon Musk (@elonmusk) June 5, 2022

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Ima buyer

Artemis 1 will be rolling out to 39B around midnight EDT.

For what? Just to play with the walker?

Tory's about to get his engines! https://t.co/VqjyWOpzeX

— Chris Bergin - NSF (@NASASpaceflight) June 6, 2022

Well...maybe?

Until I see a Vulcan actually light up, I'm going to remain skeptical.

At least until they do a static fire, I'm going to be highly skeptical that's really a ready to go engine.

Umm…it's missing a few things.