Astronauts told to return to ISS after sheltering over air leak repairs (opens in new tab)

Nearly the same experience. Had to fix an issue in a boot loader. It came down to improper setup of the memory controllers ECC engine. It would correct and ignore a single fault. If you managed to get two faults it would raise an exception that was not handled and the boot would fail. For the customer this meant that a reboot might randomly brick the unit until you go in and manually power cycle it.

Just convincing them that their problem boiled down to a single incorrect bit was difficult enough but then having to, in a day, build and successfully operate a test harness to prove the fix worked was the real stress.

I do not miss embedded engineering.

Software can be updated and patched, even if you have to manually email customers a bespoke exe that pokes bytes into a compiled dll.

Generally firmware can't be updated by the end user because there is physically no way to do so without returning the hardware. (Unless an update mechanism is specifically implemented in hardware, obv)

Pucker factor goes way up because if you ship a bug, there's no way back. If you aren't careful, you can break physical devices which can have consequences anywhere from thousands of RMAs to burning down a user's house depending on the hardware and how bad you fucked up.

The deployment process itself is about the same. Tests and more tests, including testing on prototype and/or pre-production units. Hardware testing can get wild depending on application, but I don't think any SWE would find it too surprising. Then you email a binary to your manufacturer and pray

I'm not sure distance matters. They're still stranded with virtually no possibility of rescue from the ground. Apollo 13 was extremely lucky that the hull wasn't breached, the spacecraft could still be controlled, that some very smart guys on the ground were able to devise the fix using bits of stuff known to be on board, the filter could actually be made, and, most of all, that it worked.

There'a maneuver called a "BBQ roll" where you basically set the craft to doing a barrel roll in order to prevent any one side from overheating. I image that could help some.

IIRC during transit you'd want as much mass between you and the Sun (as shielding), and as small of a cross section facing the Sun. Probably also to reduce heat reaching the propellants.

So in a cylindrical ship you'd want to have one end pointing at the Sun most of the trip. This is, of course, very different in effect on the hull compared to the repeated expansion and contraction of heating cycles.

That's not necessarily true. Even spaceships in LEO will perform temperature-driven rolls so as to distribute heat and radiation. I have to assume that long-term ships like interplanetary transport will do the same.

In microgravity, everything gets everywhere. My mother worked on NASA funded research for diagnostic spit tests to determine chronic versus acute stress, which previously required blood draws, which are a less than optimal choice in space. It's all very stressful.

I was wondering about this as well. In theory, there are also some metals and compounds that react with each other with just simple contact which result in some kind of amalgamation which can result in disastrous structural loss. Veratassium recently did a video on this kind of effect[1]. Could this be happening here?

[1]: https://youtu.be/ksn5yrsC3Wg

It seems as though the leaks are always in the Russian section? Perhaps this is why. Humans are the weak link. Damn breathers.

Most of the things that will be a common danger (that is too small to track) are tiny pieces of stuff. Think paint chips and sand grain sized objects. These can be from things that came off rockets and ships, and things we've left behind like experiments and satellites. When these tiny things intercept you at many kilometers per second it can be dramatic.

Anything larger, say a lost screw driver, would punch thru the ISS like it wasn't even there leading to some ugly consequences.

I did an internship at NASA. What they told me is that anything larger than a golf ball they track while anything smaller than, I think they said a penny, is too small to do damage. The problem is debris that's in between the two. In that case they only get a relatively short warning (it's been a while but I think it was on the order of a couple hours).

The ISS can dodge debris by adjusting the height of its orbit.

Bits of spacecraft falling off (Challenger's windshield was famously cracked by a paint chip), debris from satellite collisions, even anti-satellite weapons tests.

Debris from space. Lots of rocks are constantly falling from space from all over. Sometimes they're big and make pretty lights in the sky as they fall, often they are practically invisible.

This is just wrong. All serious issues that turned out to be safety concerns were in Russian modules. The 2018 leak you refer to here was in a Soyuz capsule and the 2021 leaks were in the Zvezda module (same place they are this time). In between there were also minor leaks in the Zvezda connection tunnel.

Maybe we can use the goop from those self sealing bike tires to have self sealing space station modules

The 10 non-Russian modules have been in vacuum for a quarter century and have done just fine despite facing more debris than in interplanetary space. So yes, this aspect is well tested. This stuff is literally part of the reason why the ISS exists in the first place.

The sealant has to be self-setting; it cannot rely on atmosphere to "dry" it, because the side facing the hole will never dry. In order for it to dry, it would have to be air-permeable, so not a good sealant at all.

So, the sealant has to be either a 2-part epoxy (harder to mix and apply), or a UV-cured epoxy. It has to adhere to a vast array of surfaces, since we cannot predict if the next leak will be in aluminum, cracked ceramic, silicone gasket, rubber gasket, plastic.... Anything it outgasses must be extremely inert, so that it doesn't cause a new problem when it reacts with a different surface (the gas on the ISS is never diluted by a giant planetwide reservoir).

Paint is obviously not a two-part epoxy nor a UV-curing epoxy; nor is it guaranteed to have fully inert outgases; finally it is not likely to be adherent to all the possible surfaces.

It's as if the situation requires a robotic diamond drill, and you propose we hit it with a big rock. The big rock won't do.

You're being sarcastic, but I would like a technical explanation of why this would not work.

Bubble gum? Like do they chew space bubble gum that they could then smoosh in the holes?

In college, we'd use toothpaste for the holes left from nails in the walls we hung up our posters with.

They did use space tape (Kapton) and epoxy for that weird case with the hole drilled in the ISS.

Duct Tape, the answer is always duct tape

can't one of them just put his thumb in the hole? duhhh

Do they literally sweat their bones away? I can imagine how it would work on molecular level via sweat / breathing, but I would expect >99% to be simply pissed and shat away.

Edit: My bad, with calcium it's the liquid filters that deal with it, not the air scrubbers.

Quoting an ISS astronaut: Today's coffee is tomorrow's coffee.

Wouldn't the calcium go out in your urine?

I think it's hard to say. Water sprayed at a ceiling doesn't congeal into a ball the way water floating in microgravity does.

Paint that would fall to the ground if it didn't stick to anything on Earth, would just be floating around in microgravity. Any dissolved gasses or moisture can usually passively sort themselves out due to their differing masses, but again, not in microgravity.

Not OP but I’d imagine the big problem with microgravity is not after application but during application. No idea the scale of that problem but obviously open cans of liquid paint are not realistic (not that anyone was suggesting they were)

But they still haven't located the leak. My blob of glue idea solves that by automatically permeating into the cracks.

wait, do they have to have matched CTE and k to the existing material... hmm

Flex Seal would be my suggestion. It works as seen on TV

I would guess they're worried about breaking something, but thanks for the clarification (and apologies for not having RTFA)

If such a conduit would connect two sections that the hatch is meant to isolate, you would have to make the conduit and everything running through it airtight, even under a catastrophic loss of air. If the conduit didn't seal as well as the hatch, which is meant to withstand hard vacuum on the other side of it, it would defeat the purpose of the hatch.

They just didn't have enough of reserved general purpose connections for future use. I guess this woild be especially the case with the Russian modules, which were literally surplus Soviet manned space army outposts(such a thing do not make a lot of sense, they did it anyway).

Those would need to be connected during docking and sealed separately anyway if you wanted to seal the hatch. More failure points.

Just a guess: Harder to build and operate with more failure modes and less opportunity for intervention.

You'd still need to pull out the utilities and close a now second hatch in the conduit to seal the thing. What would be the point?

I'm proud of us that multiple nations can coordinate such a complicated project for so long.

Somehow I never heard about that. Do you know of a good article that goes into detail about it?

Thanks

Humans can ferment?

You need 1.25 kg of gas. Candles don't consist solely of oxygen, the ones the Russians use utilize lithium perchlorate (LiClO4). When they finish burning, you are left with a lithium chloride ash (LiCl), which will be 40% mass of what you started with.

It works out to be more efficient, at least in terms of mass, to send up large tanks of compressed gas instead.

NASA used pure O2 in space until the end of the Apollo program, but the Shuttle and later used the same air we breathe today, 1atm 80% N2/20% O2. Note that in space, the pure O2 was at 0.4atm, so roughly twice the oxygen partial pressure, but only slightly more dangerous than the air we are breathing now. (You need about 0.4atm to keep your lungs from collapsing, so that's the lower limit.)

Why the difference? It's a question of what risks you were most afraid of. Even today, every single spacewalk is done at 0.4atm pure O2- trying to do a spacewalk at 100kPa even the strongest man in the world would have trouble bending his arms- so before a spacewalk the astronauts need to spend several hours pre-breathing pure O2 to get all the nitrogen out of their bloodstream before they can do a spacewalk. The Apollo program thought it was safer if the astronauts could do a spacewalk at literally any point in the mission, so that's what the spacecraft was designed around.

On the other hand, for long duration spaceflight, introducing a different pressure and atmosphere is just another potential source of health problems. Even today, the largest source of information on how human bodies last under 0.4atm pure O2 is the three Skylab missions from 1973-1974. And so the Soviets- who were always more interested in space stations than the moon- and NASA during the Shuttle era went with the atmosphere that seemed like it offered less health risks for people staying on a space station.

Okay, so what about the Apollo 1 fire? To speed up testing, Apollo 1 did two tests at the same time: the Plugs-Out Test, where the astronauts were in the spacecraft with everything running and practicing their countdown, and the Overpressure test where they pressurized the spacecraft to 1.4 atm (to mimic the pressure differential in outer space). And they did it with pure O2. So you had all of these electronics running in an environment at 1.4atm pure O2. And that was incredibly dangerous, in a way that actual spaceflight, a mere 0.4atm O2, was not. But it was just a test, another in a long string of them, and no one involved ever really analyzed it as a potential hazard.

After Apollo 1 a few things were changed: one was that they did the Plugs Out test and the Overpressure test at different times, and a lot of stuff was turned off for the Overpressure test. Another was that the Apollo capsule at takeoff was 1atm 80/20 until a couple of minutes into flight, when it dumped the cabin atmosphere overboard and replaced it with pure O2 at 0.4atm. That's why the astronauts carried little packs in their arms in all the pictures of them getting into the spacecraft, that's the pure O2 tank that they were breathing off of until they could switch to the atmosphere in the cabin after it was replaced.

They breathe a normal mixture of O2 and nitrogen at 1 atmosphere of pressure. A pure oxygen environment is horrifically dangerous if fire ever breaks out.

Apollo I disaster suggests pure oxygen atmospheres are to be avoided.

USSR, yes. But the ISS was launching during a time when USSR no longer existed and Russia was fairly isolated. Hence, "obviously": US at that time had many close allies, but Russia had only a few, and not as technologically advanced.

“What is my purpose?”

“You crawl around outside and smell for astronaut wizz.”

One thing that’s rarely discussed about spaceflight is that for the foreseeable future, it will have to happen without the animals that humans rely upon on Earth. I think this will expose just how strong that reliance is in some areas.

Some style guides distinguish between an acronym (Nasa, say the word as it's written) and initialism (ISS, say each letter)

I read their comment as a simple “oh ok I understand now” type of clarification, not a complaint.

As per submission guidelines:

> Otherwise please use the original title, unless it is misleading or linkbait; don't editorialize.

So, even if you use original title, once "Live Update" article changes, it might seem that submission did not use original title.