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MIT Bio suit design is interesting more compact, its slender, agile, it can move better and could be easy repairable, in the future some agency or nation might build a Mars colony so will new tech like 3D printed suit be posible?
The Chinese have experimented growing crops on the Moon now China's space agency has released new images from the Mars Rover including sounds
Some say a manned mission is planned
'China plans first crew to Mars in 2033'
https://nz.news.yahoo.com/china-plans-f … 53703.html
They are already testing a space station and have a suit for EVA, a Mars suit of course will be different however there is no current news in public about the Chinese Mars suit design
will they re-use ideas from other spacesuits?
Homemade spacesuits ensure safety of Chinese astronauts in space
https://www.spacedaily.com/reports/Home … e_999.html
China's self-developed spacesuits have ensured the safety of astronauts during their stay in the space station core module Tianhe and while performing extravehicular activities (EVAs) outside the module.
The space gears include intravehicular spacesuits and extravehicular spacesuits, according to different scenarios, said Zhang Wanxin, director of the astronaut suit project under the Astronaut Center of China (ACC).
Intravehicular spacesuits, which are for astronauts to wear inside the spacecraft, ensure ventilation and heat dissipation of the astronauts under normal circumstances and provide oxygen to ensure their safety once the spacecraft leaks, Zhang added.
The extravehicular suit, like a small aircraft, provides safe and effective environmental protection, environmental control and life support for astronauts when they work outside the spacecraft, he said, adding that extravehicular suits should not only meet the life support needs of astronauts but also allow them to complete extravehicular activities.
The new-generation homemade extravehicular spacesuit used in the extravehicular mission is about 2 meters in height and weighs more than 100 kilograms, with longer service life, higher reliability and better flexibility compared to the previous versions, according to Zhang.
Though heavy, the extravehicular suits used bionic structures to facilitate the activities of astronauts. All the joints of the upper and lower limbs are equipped with airtight bearings so that the astronauts' hands and feet can move freely, according to the China Manned Space Engineering Office (CMSEO).
Last edited by Mars_B4_Moon (2021-07-10 08:06:55)
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I still think we need to take the blinders off and look at substantially-different suit design. Whether gas balloon or MCP, you do it as vacuum-protective underwear with a breathing rig. Gas balloon requires a cooling system, while MCP does not (you sweat right through into vacuum). You mix-and-match whatever unpressurized outerwear garments are appropriately protective for the job at hand.
You also do NOT need 3.8-4.3 psi pure oxygen to breathe! Even 10% leaked down, that's more in-wet-lung oxygen partial pressure than breathing sea level air. And the higher pressure makes the suit stiff and bulky if gas balloon, or impossible-to-achieve with current materials if MCP.
You can make this work within the oxygenation levels of 5000-10,000 feet by using pure oxygen at suit pressures of 2.8 to 2.9 psi. Even leaked-down to 2.5 psi (more than 10%), this is still no worse that 13,000 feet on Earth. That's a more supple gas balloon suit by far, and MCP becomes quite easy (and way more supple still).
Too many monied interests talking too loudly are what keeps us from taking those blinders off.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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NASA faces new criticism, possible congressional hearing over spacesuit delays
https://www.spacedaily.com/reports/NASA … s_999.html
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Did a bit more Googling (Apollo spacesuits). I found a book by Nicholas de Monchaux entitled _Space Suit_ (amazon.com). Current price is $19.25.
The link below mentions (very briefly) the lady seamstresses who worked for ILC Dover "the sole contractor for all United States spacesuits since the first Apollo mission." Also mentions suits on Mars, in the context of: "The current suit would be useless in the extreme conditions of Mars":
...So, finding this to be interesting, I searched for images of the mentioned seamstresses and for information on Nicholas de Monchaux.
What I found, might be of interest to anyone interested in either of those topics:
(YouTube)Spacesuit: Fashioning Apollo | Nicholas de Monchaux | Talks at Google
In his talk on Spacesuits, he covers a lot of interesting history in suit design and mentions the seamstresses, as well, in section (chapter?) 14
14. The Handmade
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Yes the spacesuits were multi layer hand sown back in the day with small tubes that had the liquid oxygen running in between the layers to keep the astronaut cool on the moon from what I remember. The suits did change over time as other vendors came on line to making them.
https://en.wikipedia.org/wiki/Apollo/Skylab_spacesuit
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He guys. I posted many times about MCP spacesuits. I pointed out they're much safer and more comfortable than gas bag spacesuits. The catch is they require low pressure. Dr Paul Webb's original Space Activity Suit from 1967 used 170mm mercury pressure. That's 3.287 psi, round for significant figures to 3.3 psi. That's what NASA was intending to use at the time. Before the Apollo 1 fire, NASA intended to use 3.0 psi pure oxygen in the Command Module, 3.3 psi pure oxygen in spacesuits. That would allow 10% pressure loss of the spacesuit and still have oxygen that astronauts were used to. As a comparison, Earth at sea level is 14.69595 psi = 1.01325 bar = 101,325 Pascals. Earth has 20.946% oxygen, so partial pressure of oxygen at sea level is 3.0782 psi = 0.212235 bar = 212.235 millibar = 21,223.5 Pascals = 21.2235 kPa. At that partial pressure humans can breathe easily. I have recommended dropping spacesuit pressure even further to 3.0 psi, which is what NASA had intended for the CM. At 2.5 psi or lower you have to worry about drying the lungs, so breathing humidity must be high. At 3.0 humidity should be elevated a little, but not to an extreme. To ensure humidity doesn't fog the helmet visor, breathing air can be separated from air over the eyes. I suggested a breathing mask like a fighter pilot. Here's an alternate view.
This is a character from a Marvel movie: Ant-Man and the Wasp. This is the character "The Wasp", played by actress Evangeline Lilly. This visor design shows her beautiful eyes.
For more nerd detail, yes I recommend a head-worn helmet like Mercury or Gemini, not a shoulder-worn helmet like Apollo. The reason is a head-worn helmet can be a crash helmet for safety. Pascal Lee of NASA showed a strong preference for 4-wheel ATVs, and use of those vehicles at MDRS has shown a shoulder-worn helmet is not safe on an ATV. A motorcycle helmet is designed so the helmet breaks, your head doesn't. That makes it no longer usable after one crash. On Mars we have to ensure no loss of pressure, so I recommend a layer of closed-cell foam inside the hard shell of the helmet, then a polymer film of PCTFE as a backup pressure layer, then a comfort layer of open cell foam inside that. Another reason for sandwiching the film between two layers of foam is to protect it from tearing. The visor would have two layers of polycarbonate, both sealed to an aluminum alloy frame, which is sealed to both the hard shell and the film. All to ensure pressure seal is not broken if you fall and hit your head on a rock.
Fins from ear pieces like Evangeline's helmet are...uh...no.
Second generation suit that Dr Paul Webb and his partner made in 1971 was tested at 130mm Hg (2.5 psi, 17.3 kPa), 170mm Hg (3.3 psi, 22.66 kPa), and 200mm Hg (3.867 psi, 26.66 kPa). That suit used an air bladder vest to ensure no restriction to breathing, which acted as a counter-lung. The counter-lung and subject's lungs together have constant volume: exhaling increases the volume of the vest by the same decrease in lung volume, and vice versa for inhaling. The reason I mention this is spacesuit can be designed to circulate air through breathing alone. A one-way valve ensures exhaled breath goes to one hose, which connects to the air bladder vest. The vest connects to a canister of silver oxide to absorb CO2. That canister connects to a hose back to the helmet with a one-way valve to the breathing mask. Hoses can connect to the back of the helmet, with formed channels to the breathing mask. A T-connection in the backpack would connect the exhale hose to both the bladder and canister, with one-way valve to the canister. The inhale hose would connect directly to the canister. No circulation fans means no power required.
A pressure regulator would release oxygen into the inhale hose. Human lungs would remove O2, release CO2. Silver oxide would absorb CO2. This reduces pressure in the mask/bladder/canister. That pressure drop causes the pressure regulator to release oxygen into the breathing system. Again, no power required. If the spacesuit battery fails, the astronaut can still breathe.
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For RobertDyck re #156
This (space suit) seems (to me at least) to be a suitable subtopic for your talk on March 12th.
You arrived in the Zoom after kbd512 and I had been discussing the possible structure of the talk, so I don't know if you are interested in it.
What I have in mind is a set of twelve videos we can prepare ahead of time and store on YouTube. Then you can play the videos during the presentation, and take questions after each. A success in the opening presentation may (no guarantees) lead to an invitation to develop concepts for fuller discussion/presenation later.
We are able to use the recordings made by Mars Society using the Pro Zoom. We can work on each video during the weekly Zoom, if you like the idea.
(th)
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Dr. Paul Webb's papers
The Space Activity Suit: An Elastic Leotard for Extravehicular Activity - work in 1967, published April 1968 issue of Journal of Aerospace Medicine, Word document
Development of a Space Activity Suit - NASA contractor report November 1971, PDF
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Got 'em, Rob. Thanks.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Electric wingsuit soared into record books
Salzmann, a seasoned skydiver, teamed up with BMWi to design a chest-mounted propulsion system for his wingsuit. Lithium batteries power two carbon fiber rotors that provide up to five minutes of thrust, and Salzmann can activate the system in the air to increase his speed and push him to higher altitudes.
So add a bit more for orbit entry seems possible.
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I posted current temperature in Chat, and tahanson43206 mentioned temperature on Mars. Air temperature on Mars is cold, but pressure is so low that very little heat will be lost to air. So "wind chill" will be quite different on Mars. Ground will be extremely cold.
Mars Weather reported by Curiosity Rover: (tahanson43206 quoted temperatures in Fahrenheit, I'll quote in Celsius)
Sol 3362 Jan. 20
High: -4°C
Low: -72°CSol 3363 Jan. 21
High: -8°C
Low: -71°CSol 3364 Jan. 22
High: -7°C
Low: -71°CSol 3365 Jan. 23
High: -6°C
Low: -70°CSol 3366 Jan. 24
High: -4°C
Low: -70°CSol 3367 Jan. 25
High: -3°C
Low: -72°CSol 3368 Jan. 26
High: -3°C
Low: -71°C
tahanson43206 suggested something like a windbreaker with a sweater. However, I visualize something like a ski jacket. Of course underneath is an MCP pressure layer. And an MCP suit adds an air bladder vest that covers chest and upper abdomen. I space a spacesuit requires a thermal and micrometeoroid protection layer. The thermal layer is multi-layer insulation, which is thin aluminized Mylar with fishnet spacers, which reflects radiant heat. It makes used of the vacuum of space to act as a thermos bottle. Mars atmosphere is thin, but it's enough that the aluminum would act as a heat sink, not insulation. We need something else in the atmosphere of Mars, I suggest Thinsulate, the same insulation in ski jackets.
The outer later of a spacesuit must protect against micrometeoroids, and be able to withstand temperature swings of Low Earth Orbit: -150°C/+120°C (±250°F). I got Celsius temperatures from the Canadian Space Agency, Fahrenheit from NASA, they're the same to 2 significant digits. Outer layer of the EMU suit (white spacesuit used on ISS) is Orthofabric. That's a double layer fabric; outer layer is Goretex, back layer is Nomex with 2 threads replaced with Kevlar every 3/8". Goretex is PTFE polymer spun as thread, it's white to reflect sunlight for heat control, and impervious to mono-atomic oxygen. LEO does have some of that. Thread weight is 400 denier, it's strong yet supple. Nomex is fireproof, the same material for firefighter's jacket and pants or overalls. There was concern about fire after the Apollo 1 fire, but frankly astronauts do not wear an EMU suit inside a spacecraft, so that issue is moot. I suggest Tenara architectural fabric. It's the same as the Goretex layer of Orthofabric but with a twill weave instead of a plain weave, and doesn't have the back layer. Tenara is made in the same factory as Orthofabric, on the same machines. Or we could just use Orthofabric, it's overkill but that means the spacesuit could be used in space as well as surface of Mars.
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Mars Weather reported by InSight lander is not updated due to data transmission concerns from InSight, but it shows wind speed during a typical day above 7.5 metres per second, up to 8 m/s.
Heat loss calculator
flow rate 0, contents Water, phase change No.
vessel geometry Cylindrical Tank, diameter 380 mm, length 1800 mm, wall thickness 2 mm, content fill percentage 100%
wind velocity 8 m/s, insulation type Pyropel LD-6 Polyimide Fiber, insulation surfaces Complete, insulation thickness 30 mm
vessel material PET, operating temperature 37°C, initial temperature 37°C, heat up time 1 hour
Now to calculate heat loss at various ambient temperatures:
-3°C: 106 W
-70°C: 257 W
-100°C: 315 W
The first paper by Dr. Paul Webb linked in post #158 says heat loss of 56 kcal/hr is roughly half the metabolic heat production of a man standing at rest. He was trying to calculate heat loss of an astronaut just floating in space. He estimated an astronaut's work rate to produce 300 kcal/hr. So using 112 kcal/hr for a man standing at rest on Mars, that's 130.3 Watts. For 300 kcal/hr that's 348.9 Watts.
Power Units Conversion
Do my assumptions make sense? The heat loss calculator didn't have Thinsulate available so I chose Pyropel, and thickness of 30 mm = 1 3/16 inches. That's equivalent to a parka.
Oop! Heat loss calculator does not include atmospheric pressure.
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For RobertDyck re #162 and previous ...
Nice to see your development of this topic.
Your report of heat loss in #162 leaves me guessing ... is that for Earth, for Space ??? or for Mars?
Does "W" refer to Watts?
Does the water tank loose the stated number of ? Watts ? in a period of time? Days? Hours? Minutes? Seconds?
! Not criticizing ! Nice work! Hoping for reduction of uncertainty.
Thanks!
(th)
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Yes, "W" is Watts. As I said in post #162, I used a time period of 1 hour for the calculation. So that's heat loss per hour. It's not a human body, it's a cylinder, but tried to get as close as possible for the limitations of the calculator. Problem is that calculator doesn't take into account air pressure, so it assumes Earth. Oops. Need to start over with a better calculator.
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Convective heat transfer works as an area x heat transfer coefficient x temperature difference = energy/time. The heat transfer coefficient is an empirical function of flow conditions, and of properties like density. When density is low, so are heat transfer coefficients.
A very rough rule of thumb would be heat transfer coefficient proportional to density^0.8, for relatively ordinary external surface turbulent flow situations.
It gets in there via the Reynolds number, which empirically gets you the Nusselt number that you need. There are influences of pressure or density on thermal conductivity and Prandtl number, but they are not large, and they are smaller than the influence of temperature on those same properties.
A spacesuit has little to do with turbulent flow, so don't use that rule of thumb for the spacesuit heat transfer problem! I mention it only to illustrate just how strong the density connection to heat transfer coefficient can be.
Conductive heat transfer works on temperature difference x thermal conductivity x cross sectional contact area. Thermal conductivities vary more strongly with temperature, and not so much on pressure or density. They are empirically measured for various materials.
Radiation heat transfer depends upon radiating area x spectrally-averaged emissivity x Boltzmann's constant x (temperature of source^4 - temperature of sink^4). The temperatures have to be absolute (K or R) not relative (C or F). Emissivity is material dependent, and quite often varies with wavelength. The sink temperature may not be what you think it is. It is the temperature of only that portion of the environment that the portion of the object under study can actually "see". Planetary surface temperatures on Earth and Mars are a whale of a lot warmer than deep space. Not all the suit surface sees the same inputs or sinks, and by far!
For a spacesuited human in vacuum, convective heat transfer is not an external problem, conduction is usually through the boot soles, and radiation dominates, by far. If the suit contains gas pressure, there is an internal convection problem to solve, and it might be closer to free convection than any kind of forced convection. If the suit is porous MCP, there is no internal convection problem, but there is a heat-and-mass transfer problem to solve, with the sweat evaporating right through the suit into the vacuum.
In the thin atmosphere on Mars, there are external convection issues that get added to all the rest, but the solutions will look unlike those on Earth, because the density (and other properties) and flow situation are so different.
GW
Last edited by GW Johnson (2022-02-03 16:41:36)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For RobertDyck ....
Re #164
Thanks for your follow up!
We could have an expedition on it's way to Mars in 2+ years, after the next immediate launch window, so having a spacesuit/Marssuit design would be handy.
It seems to me (thinking out loud) that nanotechnology should be your friend in designing the undergarment, because it may support "intelligent" fabric that can sense the bends it needs to make to follow the human form underneath.
***
Slight change of focus ...
(working from memory here) ....
I ** think ** you mentioned bellows (or something like them) for the chest area, to help humans to breath.
Following the thought of "intelligent" fabric, I'm thinking of fabric that can perform the needed function.
Can you direct me to a post where the problem is described?
That would be better than repeating it for the umpteenth time.
Plus! We now have a knowledge repository capability.
No one (so far) has taken advantage of it, but since you are a major source of knowledge packets, I'll try (perhaps again?) to try to tempt you to consider it?
We have knowledge and best practices scattered over 20 years of posts.
I keep running into examples during the Post Repair.
(th)
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Post #1 has a bunch of links. But I'll answer directly.
The first MCP suit in 1967 did not have an air bladder vest. A human test subject wore it in a vacuum chamber which simulated 50,000 feet. It worked, but the subject reported restriction to breathing due to tight elastic fabric over his chest and upper abdomen. Prototype #2 was built for a NASA, his contractor report filed in November 1971. It used an air bladder vest over chest and upper abdomen, when a hose that connected the air bladder to helmet. A non-elastic fabric was over the air bladder. The bladder went over the elastic fabric suit, but it had much less strength over the chest and upper abdomen. As you inhale your chest expands. Your diaphragm causes your upper abdomen (stomach) to expand as well. That means your chest and upper abdomen squeeze air out of the air bladder, but volume inside your lungs increase. With a non-elastic fabric over the outside of the air bladder, that means air squeezed out of the bladder is exactly the same volume as air drawn into your lungs. When you exhale the reverse happens. A hose to the helmet or breathing mask ensures the bladder and your lungs have a constant volume. Ensuring constant total volume that means no restriction to breathing.
Something like this is done with navy divers for a rebreather. It's called a counter-lung. That is a bladder to accept your exhaled air, and the reservoir that provides air when you inhale. Positioning the counter-lung as a vest has the benefit that it eliminates restriction to breathing.
The Mars Society hosted a spacesuit symposium as part of the 2008 Convention. Dr. Paul Webb himself attended and gave a presentation about his MCP suit. Representatives from ILC Dover also attended. Unfortunately they pushed their latest spacesuit design. I was hoping they would learn from Dr. Webb. He was 80 years old at the time, I was worried how many more years he had. He was bright, healthy, clear headed, but that was 2008. He posted some more after that, but since his website has been taken down. I believe he passed away due to old age.
I asked Dr. Webb about cooling. The cooling system is simply sweat through the elastic fabric. My question was whether the neoprene rubber of the air bladder vest prevents sweating under the vest. He said it doesn't, the vacuum of space just draws sweat to the edges of the vest where it sublimates. I suppose that means the bottom edge of the vest, arm and neck holes would accumulate salt deposits from sweat.
My "great wonderful" addition is simply one-way valves. From the vest to a canister of sorbent for CO2, then to the breathing mask, then back to the vest. With one-way valves, you don't need a fan to circulate air through the sorbent, simply the action of breathing. So if the suit battery freezes in the cold of Mars, your suit continues to function. Human metabolism will convert O2 to CO2, the sorbent will remove CO2, so pressure will drop. Then a pressure regulator will release O2 from the storage bottle in the backpack. Electronics could monitor suit pressure in the breathing system, pressure in the O2 bottle, CO2 concentration in the breathing system. Suit controller would be a microcontroller, but with electronic connection to a smartphone held in a pocket on a forearm. The smartphone screen is accessible, and suit gloves compatible with the touch screen. But if the electronics and electrical system completely fail, the astronaut continues to breathe anyway.
Mercury/Gemini/Apollo used lithium hydroxide for the sorbent, because it's lightest. The problem is that isn't reusable. Alternatives are amine or silver oxide. Navy nuclear submarines use liquid amine, which has to be baked out periodically. The issue is gravity; liquid amine is not something you want to breathe. Bubbling cabin air through a tank of that liquid works in Earth gravity, but not zero-G. So NASA develop an amine paste (based on the submarine stuff) that can be painted on Styrofoam beads. It works and is very light weight, but large volume so too bulky for a spacesuit. The long duration orbiter pallet for Space Shuttle used Styrofoam beads painting with amine paste. But silver oxide is more practical for a spacesuit. EMU suits were upgraded for use on ISS. The lithium hydroxide (LiOH) canister was replaced by sheets of silver oxide. That canister can be taken out and put in a toaster over on ISS to bake out the CO2. However, I have a paper from the NASA technical report server about using a microwave oven to bake out silver oxide. It uses Ag2O granules instead of sheets. Obviously a microwave oven uses less electric power than a toaster oven, and consequently heats the station less, so less load on the air conditioning system. The paper is from 1996, but apparently Hamilton Sundstrand was not aware of it.
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Intelligent fabric with nanotechnology is fancy, expensive, and development for this application has not been completed. Putting that on the critical path would slow development of a Mars suit. Simply reducing suit pressure means fancy systems to pressurize are just not needed. Dr. Paul Webb's first prototype suit was designed for 170 mm of mercury pressure (3.287 psi, round to 3.3 psi), simply because at that time it's what NASA said they wanted. The A7L-B suit used by Apollo to walk on the Moon ended up using 3.7 psi. It isn't necessary. Dropping pressure to 3.0 psi (20.685 kPa) means a lot of fancy stuff just isn't needed. Dr. Paul Webb was worried a bag of liquid silicone might be required to even the pressure on the back of the hand, and another on the palm, but experimentation found they weren't necessary. Mitchell Clapp developed an MCP glove compatible with the EMU suit, which operates at 4.3 psi (29.647 kPa). Dr. Clapp found both those bags of silicone were required at the higher pressure. Furthermore his test subject reported wearing just the glove and no other part of the suit was very uncomfortable, until he put his gloved had in the glove box and decompressed to laboratory vacuum. Pressure isn't the problem, different pressure on different parts of the body is a problem.
Some people think fancy nanotechnology is necessary to don and doff (put on, take off). Because wearing a part of the suit but not the rest has this differential pressure problem. So nanotechnology would allow donning the suit with no pressure, then the whole thing tightens up evenly. But at 3.0 psi, that isn't necessary.
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The pocket in the forearm would hold the smartphone firmly. The back of the smartphone would have no insulation between phone and the elastic fabric of the suit. Perhaps a thin slip layer to hold the phone, and allow the elastic fabric to slide against the sleeve of the jacket. Body heat would keep the smartphone warm. A flap could cover the smartphone. The flap would have the same thermal insulation as the rest of the jacket, with the same Orthofabric outer shell as the jacket. Velcro could hold the flap closed over the smartphone, and another strip of velcro would allow the flap to wrap around the forearm to hold it open. So if the astronaut's arm gets cold or he/she is worried about something they're working on might scratch the phone, then they could close the flap. To view suit status or use the smartphone, open the flap.
An electrical cable would connect the smartphone to the backpack. So connection to the suit microcontroller would be via wire, and a larger battery in the backpack could power the smartphone. USB-C plug to connect the smartphone?
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MCP spacesuit - I have posted many times detailed descriptions, but we need a working prototype.
intra-vehicle pressure suit for emergency - this doesn't require micrometeoroid shield, but must be durable for all conceivable emergencies inside the ship. Must be donned (put on) quickly, and able to fit a variety of crew members.
emergency ball
portable airlock
A planned emergency run would be a must with all of the items once we are on board and its got to be timed by lots of surveillance auditors.
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SpaceX EVA suit has been unveiled.
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SpaceX reveals EVA suit design as Polaris Dawn mission approaches
SpaceX Unveils Revolutionary Extravehicular Activity (EVA) Suit
Shiny helmet shield but what I notice is the pleads in the knees.
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