71

According to Chris Hadfield's answer during his Reddit AMA: "We have a squishy thing inside we jam our nose into while we clear our ears — we scratch our nose on that." The "squishy thing" is formally known as a Valsalva device (used by both astronauts and divers for equalizing pressure in their sinuses. (Thanks to Organic Marble's comment). In addition, ...


70

That only looks like a heel! As shown here, it's a "foot restraint interface"! That said, it probably makes walking around in the training facilities a lot easier. Although that doesn't happen much - the EMUs are heavy. Source: JSC-19450 Rev. B Extravehicular Mobility Unit Systems Training Workbook This picture of a Manipulator Foot Restraint - it was ...


51

There's no advantage to replacing the air with water. you're adding weight. you're adding resistance: when you move around, water will flow around the body and because you're proposing a thin layer of water, the flow is obstructed which means it takes energy to push the water around. you're replacing the air layer (which is a reasonably good thermal ...


50

Spacecraft and space suits do NOT generate a magnetic field for medical reasons. Any magnetic fields generated are side effects of using electric motors etc. The linked question on Skeptics thoroughly debunks the idea, noting that: Gagarin was not in "critical condition" after his flight; and, Any flights in LEO are well within Earth's magnetic field. ...


48

They're simply visual differences for identification. After Apollo 11, folks on the ground had a hard time finding photos of Armstrong on the moon. Most photos were taken by him and there was no obvious way to distinguish the two suits. After that stripes were added to the commander's suit for the remaining Apollo missions. As far as I'm aware, the ...


32

The outer pane is just a replaceable protection of the inner pane against scratches, dirt, and abrasion. The helmet on the suits for Artemis missions will also feature a quick-swap protective visor. The clear protective visor is a sacrifi­cial shield that protects the pressurized bubble from any wear and tear or dents and scratches from the abrasive ...


31

The shuttle (and ISS) EMU (Extravehicular Mobility Unit) has a condensing heat exchanger as part of its ventilation loop. The condensate is stored, used for cooling, and the excess is drained after each EVA (Extravehicular Activity). Reference: Shuttle Crew Operations Manual: https://www.nasa.gov/centers/johnson/pdf/...


30

From this question on Physics.SE: But other than that, there is no reason why a man couldn't be lobbed from behind Jupiter, make a slow-down loop around the Moon, then spiral down to Earth... given some marvelous suit that will withstand the atmospheric entry. From this question on Felix Baumgartner: Note that even if he jumped from "infinity", he ...


29

A space suit could be tested to double operating pressure. This test can be done in a vacuum or in air. For the stability of the suit, only the pressure difference between inside and outside is essential. To allow enough flexibility, the pressure difference (inside to outside) should be not greater than 0.2 to 0.4 bar. Breathing pure oxygen in the suit at ...


27

They tended to suffer painful fingernails in the Apollo days, in the Lunar Surface Journal Schmitt and Cernan gave a good description of this on several pages. There were also references made in the various technical debrief documents. The problem tended to arise from the fact that the gloves are pressurised, therefore stiff. The journal also links to a ...


26

...a thin layer of water that was held down by oxygen up at the head. "Held down" doesn't work so well in weightlessness. Water would move around inside the suit, climb up the astronaut's neck and put them in danger. This happened to ESA astronaut Luca Parmitano when doing a space walk at the ISS. See Space.com's Italian Astronaut Recounts Near-Drowning ...


25

Without a glove, a space suit would basically lose its integrity. It is like not wearing a suit in the first place. Then, the question is what happens next. The closest known resemblance of such a scenario happened during a test of an Apollo space suit in a vacuum chamber: (In 1965, a tube pressurising a space suit of a ...


24

The suits used in the NBL are Class III "training only". The Display and Control Module (control panel on the chest), the life support backpack, and the SAFER self-rescue unit are mocked-up. Breathing air is supplied via an umbilical and bouyancy weigh-outs are added to the exterior of the suit. So: the soft goods (arms, legs, gloves, boots), the helmet, ...


23

I didn't know that during lunar day temperature is up to +100°C. That's how hot the lunar surface can get at the equator, about 2/3 of the way into the 2 week long lunar day. Those high temperatures were a concern; this is one of the reasons all of the Apollo landings took place within 12 to 48 hours after sunrise at the landing site. The lunar surface wasn'...


21

There is space for two full Extravehicular Mobility Units (EMUs), one short EMU, and two Orlan space suits (Russian equivalent to the EMU) aboard the ISS. They are stored in the Joint Airlock. Since the spacesuits are not part of the emergency plan, they do not store one for every astronaut (let alone a backup for each). Source: Answer by Robert Frost, ...


21

From Retro Space Images's FaceBook post: Gene Cernan scratches the itch during an Apollo 17 training session at KSC.


21

Well, an electric motor is arguably a 'pulsed magnetic device', as is a solenoid valve, but good ones try very hard to contain the fields to where they will do useful work. I suppose one could design a suit without any motors, and it may even have been done, but pumps, blowers and valves and such seem a sort of natural feature of a space craft life support ...


19

Yes The atmospheric pressure on Mars is about 0.6% of Earth's sea level pressure. That's about 0.6 kilopascals (0.087 psi). Whereas even one of the highest points on earth, Mount Everest is 33.7 kilopascals (4.89 psi). That means Mount Everest has about 56 times the atmospheric pressure of the surface of Mars. Humans wouldn't survive very long in those ...


19

The biggest issue was that the source of the liquid wasn't established and that it might have not been safe to drink, potentially causing bigger problems than Luca immediately faced. He did try to drink a bit of the fluid, and reported that it has an odd taste, so it was not his drinking water. They opted for immediate retreat back to the Quest airlock and ...


18

How about Willpower? Every Soldier learns to stand still at a parade or when they got to pledge loyalty. When I had my inauguration at the Austrian Military forces, we all had to stand still for quite some time (2-3 hours no nose or butt scratching) and it wasn't really a problem. Also, if you're concentrated on something serious (like doing work in a ...


18

The US's only "modern, real" space suit, the Extravehicular Mobility Unit (EMU), was designed in the 1970s. It has a very limited sensor suite and no automation at all. The only sensors used in the suit are A biomedical harness (with electrocardiograph electrodes) A carbon dioxide (CO2) partial pressure sensor A total pressure sensor ventilation flow ...


18

These are two microphones of the cosmonaut's headset (шлемофон - hat with headphones and microphones). Two microphones reserve each other. The ДЭМШ-microphone possessed considerable resistance to noise interference and selectivity to voice. For many decades, the ДЭМШ-microphone was installed in almost all Soviet military and professional civilian radio ...


17

You are referring to the materials protecting from insulation and the outer layers of space suits. Look carefully, they have not seen much change since the Apollo era. In Mercury, the suits were still at an rather early stage of development. They were intended as pressure-suits protecting the astronauts from decompression in case there was a leak in the ...


17

While Rory's answer is close, let me give a few additional details. The orbital speed is about 7.8 km/s in low Earth Orbit. If you are orbiting, you will not fall straight down. It just won't happen. In fact, the maximum speed would result from a minimal burn, which would take you through the atmosphere quite slowly. You will start slowing down to an extent ...


17

According to an audio transcript of the Apollo 17 lunar mission, some astronauts had a Velcro patch somewhere on the inside of the helmet to scratch their nose on.


16

Chances: Murphy's law - bad things eventually happen. Reasons: Besides (micro-)meteorites, as mentioned by @TildalWave, the risk is with the astronauts themselves. EVAs are for repairing stuff, 'plumbing', handling tools and equipment etc. It is natural to break stuff while you work. In terms of numbers, although there were plenty of EVAs in history, ...


16

The suit does not contain its own life support system. It is ventilated from a blower or, in case of a decompression, pressurized bottles within the spacecraft. It also does not have any meteoroid protection, and it tends to balloon when pressurized, restricting movement.


16

Wikipedia says: As an example, during the Apollo 12 commander's first EVA (of 3 hrs, 44 minutes), 4.75 lb of feedwater were sublimated, and this dissipated 894.4 Btu / hr. That's 2.154 kg of water over 224 minutes, or 10g/min, or 0.16g/s. Water vapor is invisible to the naked eye (2, 3). What you see e.g. when boiling water is not the water vapor itself,...


15

Yes, of course the fogging could occur, if not mitigated. You'd be exhaling and sweating pretty much same contents of water vapor wherever you are, and in a completely closed system like a helmet used in non-breathable atmospheres like on the surface of Mars would be, in the vacuum of space, or hazardous environments (hazmat helmets, full face gas masks, e.t....


14

Yes. Sokol suits are suits that are highly specialized to the Soyuz spacecraft. An easy example of the specialization is the extra room in the hindquarters region to accommodate how far they have to bring their knees in when sitting in the couches. The American suits (by which I assume you mean the ACES suits), were not designed for this purpose -- they ...


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