This means the usual consequence of a micrometeroid impact is pitting of the outer layers that may not even be noticed.
For larger objects that present a serious danger, the US Space Surveillance Network attempts to track them and predict
"conjunctions" with a zone around the ISS which extends 2km above and below it, and 25 km in each direction on the orbital path. Anything that's expected to intersect with this zone is analyzed and may result in the station being moved to get out of the way. These are mostly due to space junk of human origin. In 2013, there were at least ~70 of these "conjunction notifications", although this results in only about one move of the station per year, on average.
> "Any object with between a 1-in-10,000 and 1-in-100,000 chance of colliding with the station meets the "yellow" threshold. Flight rules say that the station must be moved out of the way in response to a yellow threshold object unless such a move results in a mission impact—"Like, if we do the burn, we're going to miss an opportunity to launch a Soyuz, for instance," explains Parris. "Do we delay the Soyuz, or do we do the maneuver?" A "red" threshold is assigned to any collision with a likelihood of between 1 (in other words, absolutely certain) and 1-in-10,000. Flight rules are more strict for maneuvers in response to red threshold objects: the station is always moved for a red threshold object, regardless of mission impact, unless a maneuver represents more risk than not maneuvering (for example, if there's a piece of equipment that's damaged on the ISS and a maneuver would exacerbate that damage)."
This doesn't help in the case of meteor showers, where the Earth is travelling through a zone full of small debris, typically caused by the trail of a comet. In those cases, the station has to rely on its shielding, but the debris sizes in those cases are almost all within the limits that the shielding can handle.
ISS travels at a very low orbit which the earth’s atmosphere does a great job of keeping clean. They occasionally manover around anything large enough to be a significant issue. On to of that space is huge and largely empty even at the speed they are traveling.
The ISS is also designed to take a hit and can generally survive similar impacts without issue.
At the typical velocities for this kind of impact, probably not. At these speeds, computer analyses ignore the solid properties of the colliding objects, modeling them as liquids, instead. (The shear resistances is just not relevant, and everything liquefies from the heat from the impact. Even that heat loss is negligible in terms of the total energy of the collision.)
Most likely, there would be fragments of the impactor and the hull, mixed together with each other and oxidized with the station air, floating about. I won't risk speculating about the fragment size, other than to say it would be pretty dang small. (I'm leaning toward "powder," but personally wouldn't rule out either "grit" or whatever "finer than powder" is.)
I would expect much more stuff to be in the air under zero gravity. On earth dust will settle on the ground but I assume in the ISS it will keep floating around.
Once it’s flashed to a plasma and turned into sub-micron dust? Probably not. The danger if there is any would be if the remaining particulates (assuming it wasn’t mostly reduced to heat, light and some basic elements) are friable.
If it were a hole, as in something punching through. These are cracks. Probably nothing passed through, these opened up beside the impact point as material buckled.
Depends on the size of the meteor. It's very likely survivable; micrometeroid protection is a design feature of the suits, which have plenty of layers, and a small hole won't cause rapid decompression. For a through-suit puncture it's going to be a lot like a gunshot wound.
If you're hit by a speck of dust or a grain of sand you're probably good for most impact sites. If you're hit by a marble you're going to be in real trouble (same is true of the ISS itself in this case).
The Wikipedia article on the topic https://en.wikipedia.org/wiki/Whipple_shield mentions that the ISS has 100 different kinds of shields on various parts of it -- presumably Soyuz doesn't have one thanks to its quite different launch and re-entry needs.
Soyuz wouldn't have much. Good thing it's in the orbital module; there are much more problematic places for a hole.
MMOD protection for visiting vehicles is actually a bit tough; they are on orbit for quite a while but have constraints around shielding. Both the new Boeing and SpaceX vehicles have had problems achieving high enough statistical survivability rates, mostly due to MMOD strikes. (Soyuz probably wouldn't pass those criteria either, but it's not asked to.)
According to Russian sources, the problem was found in the Habitation Module of the Soyuz MS-09 spacecraft, where the crew detected two small cracks, reaching 1.5 millimeters in size. Alexander Gerst apparently first discovered the leak.
The wikipedia page for Kapton [0] is interesting. "Kapton is a ... film ... that remains stable across a wide range of temperatures, from −269 to +400 °C"
Duck tape for applications needing large range of temperature stability and/or good electrical isolation. I saw it used extensively in aerospace electronics for commercial aircraft.
It gets used a lot in electronics assemblies, and places where you need high temp resistance (reflow ovens, SPACE), and low-to-no outgassing (important in vacuum applications). So it makes sense that they'd have it onboard.
Thanks for the clarification. I wonder if it is tape they have on board specifically for this kind of thing, or whether they just repurposed tape used for insulating electrical work on the ISS?
Probably kind of both. Kapton tape is extremely tough and useful for a lot of things. It's pretty common in space applications, they probably had it around for a variety of uses.
At 1.5mm, a piece of tape would come closer than you'd think to being a permanent fix...
The vacuum of space seems drastically hard to keep at bay, but consider that you're only holding in enough gas to replicate sea-level air pressure (nominally 14 PSI or so). A typical soda can is pressurized to between 30 and 50 PSI depending on temperature, beverage etc.
Supposedly the apollo command module had a pressure skin that was as thin as 0.012" (0.3mm) in places.
I did a bit of searching and found that the ISS, along with Soyuz, are kept at sea-level atmospheric pressure (14.7PSI). This is unlike pressurised aircraft, which usually operate slightly below sea-level pressure at flying altitude.
I heard a possibly apocryphal story about finding leaks in military transport aircraft -- they'd toss rolls of toilet paper around inside the craft and watch for it drifting toward and sticking to the inside of the fuselage. Apparently there was a particularly bad leak one time that simply ate the entire roll was consumed with a "FWUMP".
Even once you identify which module, there are many square meters of outer wall to find a millimeter hole in. And from what I have seen, every square millimeter of wall is more or less covered with stuff. There has to be a method to it.
Interesting, I was thinking you could use the pressure differential to flow epoxy into the hole before sealing pressure to stop flow and heating to cure, but makes sense that an epoxy bandaid would probably do just as well - probably good enough to just slap that over the hole.
Will they apply to both inside and out? Will epoxy cure properly if totally exposed to the cold low pressure of space?
Epoxy can cure in a vacuum, as demonstrated by common fabrication procedures (sort of). The temperature isn't actually that big of a thing. Space is "cold" because there's no heat but also nothing to conduct it away. It actually gets quite hot if you're facing the sun as well. Long story short though, as long as there's no gas passing through the hole, it should stay around the internal temperature of the ISS or at least close enough to cure.
IF you have spare monitor going at your office/home, its fun to watch the ISS up to second tracking locations [1].
Fun fact I learned lately about ISS: at 400km above Earth's surface, the gravity is about 80% of a normal Earth gravity. The ISS is constantly falling down but because of Earth rotation it is falling "at the edge" so to speak so it never actually fell on the ground. Hope that make sense, I'm sure you read better explanation on Wiki.
>Fun fact I learned lately about ISS: at 400km above Earth's surface, the gravity is about 80% of a normal Earth gravity.
That doesn't seem to match the movies of ISS shown, where there seems to be no (or very small) gravity. In 80% of normal earth gravity water wouldnt stay up in the air for example, and cosmonauts wouldn't be floating around in the station as we see in the videos...
The ISS is orbiting, it's falling sideways fast enough to miss the earth.
It's effectively in freefall, so although objects at 400km altitude are subject to 80% of the gravitational pull you experience on the ground, the astronauts don't notice it because they're falling sideways at the same speed as the ISS.
Edit: I just noticed that the post you were replying to included pretty much the exact same information I did, so I apologise if what I've said hasn't helped.
This is why we should use the term "free-fall", instead of "zero-gravity".
There is no way known to remove gravity. At best, you can cause the room to fall at the same rate as the things inside the room, causing the contents to float around.
It's the same principle that allows specialized airplanes to create the sensation of weightlessness, while very-much in almost Earth-surface gravity.
Well, you can go far away from large masses to effectively diminish e.g. earth's gravity though, no?
>It's the same principle that allows specialized airplanes to create the sensation of weightlessness, while very-much in almost Earth-surface gravity.
Yes, but I was confused because space offers also regular diminished gravity, and we also have the example of the astronauts on the moon, where gravity was much much smaller.
But I should have guessed that at the height ISS is it's too little to actually reduce gravity at any substantial way, and it's all the effect of the orbit/free fall.
The gravity is there, thats what keeps the ISS in orbit. However the gravity acts on everything in the ISS the same, so there is no relative acceleration in the ISS. A cosmonaut who is not touching anything and not moving relative to the walls will thus stay not touching anything, yet at the same time will still be accelerating towards the earth.
Is that what is happening? I was struggling to see a possible reason for why your post was being voted down, and unless your original post was modified, there are not many other explanations (unless people don't understand how gravity/orbits work).
I would be very disappointed if members of the HN community are voting down your posts because of who you are, rather than the content. I'd like to think we're above that sort of petty behaviour. If it were were moderators abusing their positions...
I've heard that the whole construction up there has been getting leakier over time. I wonder what exactly the threshold is these days to constitute a "slow leak"...
A rough calculation of how much it'd hurt (or not): Atmospheric pressure is 10.1N/cm^2, or 0.1N/mm^2. The hole is 2mm diameter, or ~3mm^2 in area, so the force over that area would be ~0.3N or roughly 30 grams.
It's not a lot of force. I'd be more worried about my skin sublimating, however.
I'll let someone else have the fun doing the math, but I would guess his heat radiation (convection and conduction with vacuum are going to be negligible) would be on the order of milliwatts, which'll take an hour or so to change the temperature of 10g of skin by 1°
yup bad idea alright but i stick by it...
maybe someone has a better or more germane solution than relying on an astronaut to find a leak and patch it up by hand, but the idea of preemptively mitigating leaks sounds better than waiting for a problem then correcting if it can be found...
More information:
http://blogs.esa.int/alexander-gerst/2018/08/30/slow-leak-de...
https://twitter.com/RussianSpaceWeb?ref_src=twsrc%5Egoogle%7...
http://www.russianspaceweb.com/soyuz-ms-09.html#leak