> The cylindrical piece of space junk is made of a metallic alloy called Inconel, they added. It weighs 1.6 pounds (0.7 kg) and measures 4 inches (10 centimeters) high by 1.6 inches (4 cm) wide.
I’m no rocket scientist, but I’m pretty sure that would kill you if you got hit. Though we’ll have to run a couple more tests to be sure.
"One of the items I ordered was Inconel-X, I received a 3-inch diameter cylindrical billet of the material and took it to the machine shop to have a 3-inch piece cut off to make a bearing. The shop foreman fired up a band saw and started to cut the billet. He only managed to make a small groove in the billet before the cutting action stopped. The Inconel-X had destroyed the saw teeth in just a few seconds. The foreman then tried a large power hacksaw. Those saw teeth also disappeared. I then foolishly suggested he try cutting a chunk off with a cutting torch. He fired up his cutting torch and within a couple minutes we had a billet of metal that looked like taffy."
Edge Precision on Youtube posted some videos showing making a valve body out of Inconel. It's clearly a PITA, he indexes the insert (changes the cutting edge to a new one) for every single cut. That adds a lot of time, and a decent amount of expense (carbide cutting tool inserts are cheap, but not free).
If you look at the Wikipedia for Inconel, it does actually mention that it is used as the engraving medium for black boxes: https://en.wikipedia.org/wiki/Inconel
Inconel is used in chemical plants for its extreme resistance to harsh chemicals which quickly corrode even the highest-quality stainless steels. Inconel (and its cousin, Monel) is primarily made from nickel (>70% for Inconel-X, >63% for monel). Stainless steel also incorporates about 10% nickel and 20% chromium. Nickel is very expensive, so if you can get away with using something with less nickel, you'd really prefer to! There are "recent" advances in corrosion-resistant steel with smaller amounts of nickel, like "duplex steel" - duplex 2204 is just slightly less corrosion resistant than 316 stainless, but contains 4% nickel instead of 10%.
You only use inconel when you absolutely cannot use anything less. It costs $2.50/lb compared to $0.80 for 316 and $0.40/lb for mild steel (standard run-of-the-mill steel). Not sure what 2204 costs these days, but will be somewhere between 316 and mild steel. No one wants to pay three times more for material if they don't have to, and also pay extra for specialized machinists who are confident working with a somewhat rare material.
Materials scientists are working hard to create new, cheaper alloys with high corrosion resistance, and it drives a lot of really cool new science! Over the past 1-4 years I've seen some super interesting articles here on HN about new science being discovered around this, but I can't find them at the moment.
That said, Inconel is only 4% denser than run-of-the-mill steel, so it's not going to make a difference which of these alloys fall from space onto your house or head.
I think it will make difference which alloy falls from space, because much more of the inconel will be left after the fall. After all, they use it in spacecraft because of how well it handles high temperatures like reentry.
It handles better high temperatures than steel in the sense that it retains its strength at high temperatures, but which are still much lower than its melting point.
This does not imply that Inconel is more resistant at vaporisation than steel. It is possible and even probable that it is less resistant (Inconel X has less chromium than many stainless steels and pure nickel has higher vapor pressure than pure iron, so it evaporates more quickly, but the behavior of alloys may be different from their components).
Therefore it is not certain that more of the inconel will be left after the fall, it is quite likely that less will be left than from stainless steels with high chromium content.
Interesting, I had assumed breakup happened because of structural failures related to aerodynamic pressure and weakened material properties as the material approaches melting. But of course vaporization would account for most of the “burning up” during reentry
Also used in oil/gas downhole in corrosive environments (primarily CO2/H2S). Typical tubing size is 2-7/8", which is ~10.4 lb/ft x thousands of feet. Not cheap.
Oh my gosh. I did some downhole work analyzing the corrosion of casing and tubing. It boggles my mind that some wells produce enough to justify that. I should have known - it's "only" 5-10x more in material cost; just belies my typical rule-of-thumb intuition.
You would have to have some pretty bad luck to be hit by space junk like that. Not saying it's a good thing or anything, just that the odds are pretty astronomical.
The more junk the higher the probabilities of an accident. It doesn't have to reach two digits probability for it to start to be a problem. Densely populated areas + high likelihood of space debris could lead to unacceptable risks. Although I agree the actual danger is in the orbits and with deployed satellites.
Densely populated areas probably reduce the risk for objects this size, as skyscrapers and subways are harder to go through vertically (when starting from space) than bungalows and cars.
Most junk burns up in the atmosphere and so is harmless. Large or dense things are a big problem though. Satellites need to be designed with respect to how they break up on reentry.
> Also, tell the family they just have “bad luck”.
It's not wrong, though.
The Earth's surface is slightly over 500 million km².
Let's say that something landing within a 10m radius of you represents a hit. That radius is about 314 m², or
0,000314 km²
If my math doesn't fail me, if we partition the globe into discrete areas equivalent to that 10m radius, the odds of something landing on your area would be around 1 in 10^12.
That's the chance of one specific person being hit. But I think you'd want to calculate the chance of any one person being "hit", which is roughly ten billion times higher than that, and uncomfortably likely (if people were actually 10m wide).
Except that neither human nor satellite distribution is even across the global surface, and we actually tend to put our satellites above the human-populated areas so that they can service those humans.
Including the nigh-unpopulated polar regions would massively skew the probabilities, for instance, especially since most satellites aren't in polar orbits either. It's still an infinitesimally small likelihood of being hit by one, of course.
According to Clark R. Chapman (2007) [1], the "Odds of Dying in the U.S. from Selected Causes in a Human Lifetime" have Regional Asteroid/Comet Impact as 1 in 1,600,000, while the Odds of winning the PowerBall are 1 in 195,249,054.
Yes, but an asteroid doesn't have to be earth-ending to ruin agriculture for a year. This is similar to the civilizational threat of volcanic supereruptions.
Homes are much larger than people and people are always in their homes. And even if you were home it’s not like it would 100% penetrate a floor you’re on or wall or whatever.
US houses are notoriously not as well built as in other places in the world. Where I live at the moment for instance is concrete all around, including the roof. I would be surprised if this falling on it would do anything at all and surely wouldn’t penetrate.
Where I live, the common construction for houses is to have reinforced concrete slabs as the floors and ceilings, with the walls being brick except for the load-bearing reinforced concrete columns. The ceramic tiled roof (when there's one) goes above the reinforced concrete ceiling. More than once, I've read about accidents in which Brazilians fell (sometimes to their death) through the ceiling of a USA home, and that's because we simply don't expect the ceiling to be so fragile; our intuition is that the ceiling is as strong as the floor, and that we can walk normally over it.
To those from countries with a similar building culture, USA houses feel really fragile; for instance, what do you mean you can punch a hole in a room's internal wall? We expect these walls to be made of brick.
I have no idea how fast it was going when it hit, but as it is more than 10x the mass of a 50 cal, I wouldn't rely on the assumption that protection from the latter is also protection from the former.
Sure, but that concrete would break up in case of earthquake and kill a lot of people with debris. US houses are much safer in case of earthquake which is much more likely than space debris.
There are places in the US that that type of build is the norm.
Beyond that, “better built” in what sense? I’ve lived in the places that are built like bunkers (literally; Guam builds for direct typhoon hits). They are fine, but aren’t built for earthquakes, energy efficiency, or any other metric that’s more relevant in other parts of the world.
What's the smallest meteorite that would still be "penetrative" to a human body? Eg not falling space dust and also taking into account terminal velocities of smaller particles.
you are living in an ex-ww2 bunker? here in the UK it would have gone right through the roof tiles and the plasterboard of the ceiling. same for the several dutch houses i've lived in.
You can tell it’s a joke because they stated their intent to keep quiet, but didn’t. The humor comes from the surprising difference between what was stated, and reality.
- "Apophasis (/əˈpɒfəsɪs/; from Ancient Greek ἀπόφασις (apóphasis), from ἀπόφημι (apóphemi) 'to say no')[1][2] is a rhetorical device wherein the speaker or writer brings up a subject by either denying it, or denying that it should be brought up.[3] Accordingly, it can be seen as a rhetorical relative of irony."
It was obvious sardonicism. Sardonicism is often humorous. The point was to mock those who criticize private companies but not government institutions. An underlying point was that they should be treated equally but aren't.
The limits of text communication, right? A wink or other gesture or knowledge of this person's previous jokes would let a human to easily identify it as a joke or not. Netiquette would be to add "/s" or an emoji to add more information to the channel.
in a way, explaining humor is funny in and of itself. but ya. low fidelity communication and subtly are not friends especially to a technical audience.
> The uncontrolled disposal of the pallet, however, was not part of the original plan. It was made necessary by a disrupted spacewalking schedule following the failed launch of a Soyuz rocket in 2018, which forced NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin to make an emergency landing in the Kazakh steppe. This event led to a backlog in the disposal of such equipment. Normally, old batteries would be placed inside an HTV (H-II Transfer Vehicle) and jettisoned from the ISS to burn up on re-entry.
> However, in late 2018, an HTV departed without this battery pallet due to the rescheduled spacewalks. As the battery replacement mission continued, and with no more HTVs of the old design expected to arrive (they are being replaced by the HTV-X cargo spacecraft), the decision was made to jettison the pallet independently.
I’m also curious which part of your auto or home insurance policy may call out space junk as covered or not. Maybe similar to a plane crashing into it.
I jokingly asked my insurance company this on Twitter a few years back when there was a Chinese satellite crashing and my house was in the possible path. They actually replied and the answer is yes - I would be covered. I was surprised actually that they replied at all and that I was covered!
Definitely worth the customer goodwill for something that is extremely unlikely to happen. Plus, for an insurance company the financial impact of replacing one house is completely routine. Yet, being able to advertise your situation would be golden.
The previous article from when the incident had just caught NASA's attention mentioned that the homeowner intended to go after the government for costs, but explained that it could be complicated if the part turns out to be owned by JAXA, since then either the owner has to go after JAXA or NASA has to work something out with them.
The cylindrical piece of space junk is made of a metallic alloy called Inconel, they added. It weighs 1.6 pounds (0.7 kg) and measures 4 inches (10 centimeters) high by 1.6 inches (4 cm) wide.
But are you allowed to sell it? I'd think it still belongs to NASA. If an airplane flies over your house and drops an engine into your back yard, you can't just auction it off but have to hand it over to the authorities. Or if someone – accidentally or not – throws his Rolex watch into your window. He'll have to pay for the damage, but the object is still his property.
That doesn't matter, in most jurisdictions stealing trash is still stealing. If I'm disposing chemical waste in your backyard, do you automatically become the owner?
How can you steal trash?? You're literally trying to get rid of it?! I am pretty sure you're never going to jail for taking someone else's trash (maybe you can get in trouble for trespassing or something like that, but for stealing?!?).
I think you'd be so hard-pressed in finding a court that would convict someone of "stealing" for having been in the path of trash that was jettisoned through two stories of your home as for the prospect to be infinitesimal
Inconel is tough stuff, melting at around 1400°C. However looks like re-entry temps can range from 2,900°C to 6,650°C. I guess the question is if it's hot enough for long enough to melt a large lump. Apparently not in this case.
As evidenced in the photo, it probably did partially melt and deform; but getting hit with a slug of molten metal is unlikely to be any better of a result. What's more important here is the boiling point.
Not that much more important. Even if the metal is only liquefied, under the airflow it'll be prone to breaking into droplets with much lower terminal velocity, with much the same effect of reducing the mass that can actually hurt anyone. Unless I'm missing something big about the dynamics?
Can't they aim a bit better while jettisoning stuff or is re-entry that chaotic? It looks like they are relying on stuff burning off as they go through atmosphere but I don't see how that can happen for a roundish chunk of metal. But I am no nasa engineer so who knows
The earth surface is 70% water, surely you can aim for an ocean
Atmospheric drag is the main determining factor, and the atmosphere at high levels is thin, but not particularly flat, and difficult to measure. Add in the fact that orbital objects move at ridiculous speeds, and the errors quickly add up.
> The batteries, nine in total, were released on 11 January 2021 and will undergo a natural reentry, which is now predicted for around 18:56 CET on 8 March +/- 0.4 days.
Half a day of uncertainty! This was a day before reentry!
The batteries from this incident are typically returned to Earth in a controlled manner via a cargo spacecraft, but a failed launch required an alternative plan.
> The uncontrolled disposal of the pallet, however, was not part of the original plan. It was made necessary by a disrupted spacewalking schedule following the failed launch of a Soyuz rocket in 2018, which forced NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin to make an emergency landing in the Kazakh steppe. This event led to a backlog in the disposal of such equipment. Normally, old batteries would be placed inside an HTV and jettisoned from the ISS to burn up on re-entry.
> "NASA specialists use engineering models to estimate how objects heat up and break apart during atmospheric reentry," they added. "These models require detailed input parameters and are regularly updated when debris is found to have survived atmospheric reentry to the ground."
So, yes, they do rely on stuff burning off as it goes, but with some understanding whether that should actually happen.
Yes, for big parts where they know it will come down to the surface they try to aim for water, like they do with all the rocket boosters etc.
However that's still risky, so given the choice between (fast descent and aim for ocean) and (slow descent to burn up in atmosphere) they almost always aim for the latter.
Plus you can only "aim" something like a rocket booster or a satellite that can still generate a little thrust of its own. This case was more like throwing your heavy backpack from the top of a skyscraper – 3 years ago(!!). That's impossible to control. Plus it has been an emergency solution anyway, see https://www.space.com/space-station-jettisons-huge-space-jun...
Your question is vague. You're not dropping something off a cliff it's moving and 400km up and 25,000km/h.
Any object coming from the ISS will be going 25,000 km/h. I don't think "aim" is the word since the Earth is moving rapidly beneath the object. There's no stationary point to aim at. Plus once the object of whatever shape in the atmosphere drag which causing friction to burn it up is not controllable. It would break apart and each object with different mass now has its own path and velocity.
I'm amazed any of it works as well as if does now.
Anything released from the ISS will initially be in an orbit very similar to the ISS. That's because the initial difference in velocity between the object and the ISS will be measured in meters per second or less (which is small compared to the orbital velocity measured in kilometers per second).
Then the orbit of the released object will start to slowly decay because of (at that altitude, a very small amount of) air resistance. The details of that depend on the shape, size and mass of the object. It can even depend on unexpected solar activity which can cause the Earth's atmosphere to puff up minutes[1]. The ISS counteracts this by periodically boosting its orbit.
The longer the orbital decay takes, the more the uncertainty adds up. The fix to accurately "aim" an object, is to strap it to a rocket and perform a deorbit burn, to slow down from orbital velocity. This way the reentry process can be more reliably aimed at the middle of the Pacific or something like that. But that's expensive.
It might not be easy to aim anywhere if the object is expected to do multiple rotations around the earth before ending up anywhere. It would be good to have confirmation from a specialist.
I agree: specifically, I think that controlling the point of impact is possible but requires equipment (rocket motors, a heat shield, navigation computers) which of courses costs money to get into orbit and can be used only once.
I'm very curious how a FL man deduces that the object was ISS debris, vs random explosive, plane part, university pet project, etc and all other million things that could potentially caused the damage
A deorbit of 3T of ISS cargo is significant, and there was a decent amount of press in fairly mainstream news sites leading up to the re-entry. It doesn't seem that unlikely that he, or someone he knows, had heard about it and connected the dots.
The Kennedy Space Center is on the east coast of Florida. The house was on the west coast of Florida. And they're about 180 miles (290 km) apart. I guess from the point of view of space, they're not very far, but from someone living in Florida, I'm not sure I agree.
I thought the same thing. I’m sure he’s the primary investigator of this case, but I still wonder how he came to suspect the ISS for a solid soda can ripping through two stories of his house.
I'm surprised, it looks nothing like a cannon round, also, as far as I'm aware the military has no kinetic bombardment it uses, I know a couple of years back they talked about the rods of gods system, but outside that I don't believe there are any rounds in the military that are just massive chunks of metal?
This time it was. Maybe there's actually a bunch of unreported "dark debris" hitting roofs of people who aren't NASA aficionados with Xitter accounts :)
I wouldn't be surprised if they haven't, especially with the ISS being an international station. Good luck getting one national agency to accept enough of the responsibility! And then the red tape even if they clear that hurdle...
Someone should've suggested to them that they were originally meant to be disposed in a controlled manner via a
[Wrong] ~Russian vehicle that was delayed (they opted for uncontrolled reentry because the batteries were risky to keep around at the ISS, the controlled disposal vehicle was delayed and they had figured the batteries would be vaporized during reentry)~
Japanese vehicle, the crew for the disposal being delayed due to issues with a Russian vehicle, so they could instead blame the Russians in some manner. It'd be tricky to rephrase, but that hasn't stopped the media previously.
Luckily it wasn't SpaceX, else every mainstream outlet's headline would be some form of "Elon Musk, owner of Starlink, drops space debris onto unsuspecting Florida man, nearly kills son"
Close. They were meant to be disposed via controlled entry on a Japanese craft, but the astronauts that were going to do the work were delayed due to issues with Soyuz, and they couldn't keep the Japanese craft around indefinitely due to other conflicts.
Ah that makes much more sense! I recalled that it was Soyuz that was delayed, but had been thinking that if they were disposing they'd probably do it via Progress and so, was a bit confused. I remembered that the reason for the uncontrolled disposal was the Soyuz delay and just went with that.
Probably goes without saying. People should be allowed to be safe in their home without being possibly killed by space debris. If not, humanity is doing something wrong.
Meteors exist, and there's nothing you can do to stop it, aside from clearly uneconomical shielding of every roof of every home.
Its arrogance to think we are immune from unexpected and sudden death because we are humans.
Also, cars and trucks occasionally do drive through homes, if the homes are next to large roads. Its rare, but far more common than space debris.
Also, keep in mind these space debris, even if they hit homes, are unlikely to kill, a 10cm diameter ball (Aka 80cm^2 = 0.008m area) is unlikely to hit someone in a 100m^2 home.
Why is getting killed by space debris is less pleasant than getting killed by a meteorite?
The point is there is a background risk of sky-born peril. There is tremendous opportunity in putting things in orbit. Given the frequencies of any damage or injury from extra-atmospheric debris, of our or nature's making, it would be surprising if the marginal benefits gained from optimising for more safety would outweigh the opportunity cost.
We should look for cheap optimisiations that reduce the risk of peril. But eliminating the possibility is impossible; pursuing massive reductions in risk absurd.
That's, uh, not how it works actually. Everything is cost benefit trade-offs. We can't guarantee total safety.
NASA, for instance, estimates the risk of a civilian being killed by reentry , and has a formula that says how much money they can spend to eliminate how much risk.
I’m no rocket scientist, but I’m pretty sure that would kill you if you got hit. Though we’ll have to run a couple more tests to be sure.
Home owner says it tore through two floors: https://twitter.com/Alejandro0tero/status/176872903149342722...