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129

I believe it was John Young, during an Apollo 16 EVA fell to the lunar surface. Though awkward, he got up unassisted by attempting a series of what looks like push-ups until he was able to get himself to his knees. Then he had little difficulty standing up from resting on his knees. This YouTube clip shows how he did it. Apollo 16 astronaut falls and ...


76

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 - ...


75

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, ...


59

As long as neither spacecraft nor the astronaut are accelerating or decelerating, the relative speed of the spacecraft and the astronaut remains the same. So the astronaut will hover near the spacecraft. The actual velocity is irrelevant here, it's the same principle with every spacewalk: the ISS is moving at about 27,600 km/h, yet the astronauts do not "...


57

As always, the Apollo Lunar Surface Journal is a treasure trove of annotated examples. During the later (J) missions in particular, Ed Fendell, remotely operating the rover's TV camera, managed to capture a few for posterity. Falling forward (straight or a bit to one side) happened to several moon walkers, and getting up was not that difficult. Only Charlie ...


43

These cameras had magazines that could be exchanged in the middle of a roll (and that was one reason NASA chose them). Here's a photo of John Young exchanging a magazine during an EVA on Apollo 16: So, no need to wait until they were back in the LEM. This long PDF has more detail on the film change process. A standard Hasselblad magazine has a ...


41

Tom Jones talks about it some in his memoir "Skywalking" when he describes an EVA carried out on shuttle mission STS-98: Inside the airlock when it is pressurized Through the helmet shell, from the world outside the space suit, came a muted, sporadic tinkling sound, the result of minor collisions between our drifting tools and the airlock walls. ...


36

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 ...


35

It turns out that outer space is not a perfect vacuum: there are a few hydrogen atoms per cubic centimeter. (reference) For large X, non-relativistic physics, the astronaut and spacecraft will stay close enough to each other. Once X gets small, and you approach the speed of light, these hydrogen atoms could slow down your spacecraft. Therefore, to maintain ...


32

Despite Charlie Duke's concern about it, given that the PLSS is massive, and would shift an astronaut's center of gravity far back from their natural distribution, it would be surprising if the designers hadn't anticipated the possibility of a fall. This view of the PLSS shows that the back side of the backpack is almost a single unbroken shell: ...


31

A nitrogen cold jet thruster system called SAFER (Simplified Aid For EVA Rescue) is part of the US EVA suit ensemble. If a crewperson gets loose they can fly back using SAFER. (Image source) SAFER is not used in the normal course of an EVA. There is no other propulsive system on a US EVA suit. SAFER was deemed necessary for the ISS era because either ...


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

Although not the incident you are referring to, an incident outside the ISS in 2013 during EVA 23 is a good reference point for your question -- where Italian astronaut Luca Parmitano had water leaking into his helmet. My answer is based primarily on information in the official NASA report regarding the incident. There is also a good summary on this site. ...


29

Although this has indeed "worked to bits" on the Physics and other SE sites it's worth looking at, for the sake of Space Exploration, the interesting history behind the analysis of the falling cat. For the fully rigorous description of the cat's righting reflex - perfectly in keeping with conservation of angular momentum - only came about because it was ...


29

They did. Apollo 15, 16, and 17 has an EVA to recover film from cameras in the Scientific Instrument Module Bay (SIMBay) on the Service Module to bring back inside. This table, linked, shows all the Apollo EVA's. Table of EVAs Worden (Apollo 15), Mattingly (Apollo 16), and Evans on Apollo 17 spent about 3 hours total on EVA. Some good articles on these ...


28

This is a great question. I wanted to provide an answer which cited some specific, real-world situations. Currently the only people in space are those aboard the International Space Station. If anyone could potentially get into a scenario as you describe in your question, it would be them. Currently, on spacewalks, a huge number of safety procedures are ...


27

This video published on YouTube on Zero-G: "Movement in Microgravity: Skylab to Space Shuttle" 1988 NASA Weightlessness Footage, starting at 2:10 into it, shows a Skylab astronaut doing a front roll and a spiral roll in the Skylab Orbital Workshop without touching anything to push against to change his orientation. And the same video from 5:45 to 6:00 shows ...


27

JWST is being launched on an Ariane V with a cryogenic upper stage. That upper stage has to be used immediately to launch it on a trajectory to the Sun-Earth L2. The stage operates on batteries, and the cryogenic fuel is boiling off. So there would be no time to do anything even if you deployed the telescope before departure. Furthermore, the deployed ...


25

The CSM was always able to be depressurized, since the contingency procedure for getting back from the LM to the CSM, in case the docking mechanism would fail to latch or the doors were unable to open, was to go around via the outside (i.e. open the LM hatch and CM hatch and transfer via an EVA): An Apollo contingency transfer is required if the lunar ...


25

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, ...


24

The Pistol Grip Tool has some features not found in DIY or even professional cordless drills. It can control its torque and speed exactly, and torque/speed/turn count values can be programmed. It also measures and records the applied torque. In general, space tools also need to be usable while wearing thick gloves, and they need to work in extreme ...


24

This was mission STS-61B. The giveaways are the ACCESS payload box and the Mexico logo on the PAM-D sunshield. The last task of the first EVA was to deploy a small satellite (the radar reflector) to be used for station-keeping experiments. Ironically, the shuttle radar was failed, so the targetting was all done visually. This was definitely part of an ...


23

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


23

Let's look at Newton's first law: Law I: Every body persists in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed. In modern mathematical speech, this can be stated more precise. In an inertial frame of reference, an object either remains at rest or continues to ...


22

Spacesuit designers and extravehicular activity (EVA) planners would probably prefer if spacewalks only took part in the Earth's shadow. From the spacesuit design perspective, one of the biggest issues is heat rejection, not heat retention. This is because of nearly nonexistent convective heat transfer (conduction and advection) in near vacuum in LEO so the ...


21

I feel this sort of question benefits from a series of thought experiments. Imagine instead that you've got two astronauts, side by side, zipping through space at some constant speed. They're kind of sweet on each other so they're holding hands. Awwwww. But then they suffer a cruel change of heart and stop holding hands! What do you imagine would ...


21

There are good diagrams of the Kontakt docking system in the Mir Hardware Heritage document by Portree. As stated in comments, this was an unpowered, misalignment-tolerant docking system that did not incorporate a transfer tunnel. ... a spring-loaded probe docking system, called Aktiv (“active”), which was designed to penetrate and grip a “honeycomb” ...


20

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 ...


20

Once the astronaut & space vehicle part ways, they're on two separate orbits. If the force that separated them is impulsive (instantaneous force in a single direction - as in pushing off the spacecraft and forgetting your tether) those orbits intersect at the point of departure. If you can wait 1 rev (about 90 minutes in LEO) you will cross the ...


20

The Big 131 are Pump Module (PM) R&R Flex Hose Rotary Coupler (FHRC) R&R Interface Heat Exchanger (IFHX) R&R Solar Array Wing (SAW) Bearing Motor Roll Ring Module (BMRRM) R&R SAW Electronics Control Unit (ECU) R&R Ammonia Tank Assembly (ATA) R&R Nitrogen Tank Assembly (NTA) R&R Main Bus Switching Unit (MBSU) R&R External (EXT)...


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