Two objects colliding can send debris into different orbits. Combined kinetic energy and mass differences can send debris to many different orbits.
A golf ball hitting a bowling ball or basketball, both traveling at 30 units of speed can produce quite a fast golf ball. Not all of the debris will safely burn up.
At the speeds we're familiar with, basketballs and golf balls have elastic collisions. At orbital speeds, satellites are nearly inelastic. So fragment exit velocities lie between the two initial velocities, kv1 + (1-k)v2 for some k that depends on where each fragment came from. If they're colliding, the velocities must be somewhat different, so the weighted average speed has to be lower than orbital speed. So fragments usually don't survive many orbits.
Very well put. It also seems like there's a limit to how bad Kessler syndrome can get. The more debris there is the more collisions, but the more collisions the quicker the debris collides with itself and de-orbits.
That's what I was thinking, Kessler syndrome should be impossible for objects in LEO since all debris orbits decay rapidly (probably 99.9% enter the atmosphere and burn up in minutes, the rest in hours)
Possibly. But more likely the thrust from escaping gas will push it in a direction to either slow the orbit down or make it more eccentric and unstable.
Right, if there's something like a small hole in a pressure tank, it's very unlikely to be aligned exactly with the CG, so the tank will spin around and the net thrust will be near zero.
If a pressure tank splits in half, both halves will fly away but that's a very inefficient way of using the energy in the gas, so the added velocity will be a small fraction of the speed of sound in the gas, which is 1/6 of orbital speed for hydrogen, less for any other gas.
You can't really get much of a chemical explosion because the fuel and oxidizer both disperse very quickly in space.
Just to elaborate the correct reply given by the others, the perigee of all fragments will be less than or equal to the altitude at impact point. If that's low enough, they will all eventually decay and deorbit. Even the fragments in elongated high-eccentricity orbits will have their orbits circularized by lowering apogee (the perigee is never going to rise) due to air drag. It will eventually spiral into the atmosphere. Here is the best visualization for this phenomenon - the Gabbard plot.
You're right that all the fragments will pass roughly through the impact point in orbit. But it's not always the periapsis.
1. The normal or anti-normal delta-v imparted by the explosion/fragmentation (i.e, the velocity imparted perpendicular the plane of initial orbit) will cause the orbital plane of the fragment to change. The new orbit will intersect the old orbit at the impact point. Meanwhile, the eccentricity (the stretch of the orbit), semi-major axis (the size of the orbit) and displacement of periapsis from the impact point (the orientation of the orbit) remains the same as the initial orbit.
2. The prograde and retrograde delta-v (velocity imparted tangential to the orbit) will cause the diametrically opposite side of the orbit to rise or fall respectively. Here too, the new orbit intersects the old orbit at the point of impact. But since the impact point isn't guaranteed to be the periapsis or apoapsis, the above mentioned diametrically-opposing point also cannot be guaranteed to be an apsis.
3. The radial and anti-radial delta-v (this is in the third perpendicular axis) will cause the orbit of the fragment to either dip or rise radially at the point of impact. Again the impact point remains the same for the new orbit. So the new orbit will intersect the old orbit either from the top or the bottom. The new orbit will look like the old orbit with one side lowered and the other side raised about the impact point.
So none of three components of delta-v shifts the orbit from the impact point. You can extrapolate this to all the fragments and you'll see that they will all pass through the impact point. The highest chance of recontact exists there. However the perturbation forces do disperse the crossing point (the original impact point) to a larger volume over time.
Edit: Reading the discussion again, I get what you were trying to say. And I agree. The lowest possible altitude of the fragments in orbit (i.e the periapsis) is the same that of the impact point. So if the impact point is low enough to cause drag, the orbit will decay for sure. There is nothing that demonstrates this better than a Gabbard plot [1][2] - the best tool for understanding satellite fragmentation.
>But since the impact point isn't guaranteed to be the periapsis or apoapsis, the above mentioned diametrically-opposing point also cannot be guaranteed to be an apsis.
You're correct on the generalized case of the math here, no argument at all, but this also feels like it's getting a bit away from the specialized sub-case under discussion here: that of an existing functional LEO satellite getting hit by debris. Those aren't in wildly eccentric orbits but rather station-kept pretty circular ones (probably not perfectly of course but +/- a fraction of a percent isn't significant here). So by definition the high and low points are the same and which means we can say that the new low point of generated debris in eccentric orbits will be at worst no lower then the current orbit of the satellite (short of a second collision higher up, the probability of which is dramatically lower). All possible impact points on the path of a circular orbit are ~the same. And in turn if the satellite is at a point low enough to have significant atmospheric drag the debris will as well which is the goal.
No worries. I think I could have been more precise in my wording. :)
My comment is based on the hunch concerning physical calculations and interactions from an engineering physics degree and way to many hours in kerbal space program a decade ago.
Thanks! I figured that you had a reasonable understanding in this subject. But I still couldn't help just laying it out. I have some background too - as a professional.
> I doubt the ROI would be so high if organic results stood any chance.
This is just the same fallacy. In what world are people going to organically share ads for this company on their Facebook feeds? Who is going to Google the company name before they know about it?
Every business needs to proactively acquire customers.
Distribution and CAC are top of mind values for any growth business. It has been this way long before Google and Meta existed. Digital advertising actually makes it cheaper and easier than ever to acquire customers at scale.
Sounds like ads will just get replaced with covert word of mouth enticements. Want to get people to know about your product? Send free samples to influencers. Maybe even fly them out to CES and put them in nice hotels so they can experience your product announcements/demos. All of this is "unpaid", of course.
Assuming the influencers pay taxes, this doesn’t seem like something that can’t be addressed - we should be requiring influencers to prominently disclose incentives that could result in conflicts of interest.
I would prefer a world that returned to the older '30 second blip (for the only) sponsor of the program' ad, which also seemed to be of the limited form: Here's Product X, it does Y, which makes your life better because Z. Informative, dry, stated by an announcer in a calm and not demanding way.
A lot of people enter the company or product name into the browser's search field and reach their intended target through an ad at the top of the results. If they proceed to purchase something, does this count as a conversion? I think it does. Unlike traditional advertising, this didn't influence the customer's decision to buy at all.
I'm concerned that companies spend their advertising budget on these redirects because those have the best metrics, instead of actually making the brand and its products more known.
Going a level deeper, more information can be gleaned for how closely modern technology mimics kids toys that don’t require manuals.
A punch card machine certainly requires specs, and would not be confused with a toy.
A server rack, same, but the manuals are pieced out and specific, with details being lost.
You’ll notice anything with dangerous implications naturally wards off tampering near natively.
Desktop and laptop computers depending on sharp edges and design language, whether they use a touch screen. Almost kids toys, manual now in collective common sense for most.
Tablet, colorful case, basically a toy. Ask how many people using one can write bit transition diagrams for or/and, let alone xor.
We’ve drifted far away from where we started. Part of me feels like the youth are losing their childhoods earlier and earlier as our technology becomes easier to use. Being cynical of course.
We need to look at this from an inevitability perspective sprinkled with Murphy’s law.
Adding money to politics corrupts the will of the people, it will with 100% certainty, and the people who corrupt it will eventually end up in power. Super PACs have destroyed this country, allowing technigarchs to buy elections. You can’t prove or disprove control anymore, it’s pure capital infusion.
Lobbying is a scourge. I went on a trip to the heart of DC and got toured around by a lobbyist. They make you feel so relaxed and are very convincing how they’re helping as they guide you through how they work. Many others with me were very convinced and even defending the practice as necessary after my skeptical commentary. These are professional salespeople, wining and dining our politicians using corporate money. This is entirely disconnected from what is actually good for our society, is pure pay to gain. It has just seeped out and overflowed to the digital realm now.
A government having a dossier on every citizen would have been a headline 50 years ago. Today it’s open and free to corporations also. We’ve crossed the line and lost it miles away.
Now we have literally made up monetary systems that big banks can play with at will to extract as much wealth from solo investors, and effectively legalized insider trading and crypto scams.
If prices don’t drop (which I assume the opposite), we’re heading for another world war. China will invade Taiwan in a few years, Russia will keep the land and rearm for parts 5 and 6 into Poland and Europe, the US will be forced to dig into Venezuelan oil, and god knows what else.
This doesn’t feel like a bump on the road, this feels like an end to an era. I hope I’m wrong.
It's even worse when you look at the studies of child outcomes based on if their mother stayed with them during their childhood vs working/daycare.
It is without doubt beneficial for children to have their mother with them in early childhood. This work over all else society is harming the next generation and ripping new mothers away from their babies a few weeks/months after birth.
The problem will solve itself; political leanings are heritable and in the past couple decades conservative birthrates are significantly higher than liberal birthrates, so eventually the genes that incline people towards prioritising work over family will be bred out.
I have a similar theory, that desire to procreate is heritable, in a way that was previously inextricable from desire to have sex. With easy birth control, those desires can now be fulfilled separately. We're still working through the mass die-off of the genes that mostly just wanted the sex half of the equation.
In a few generations, most everyone alive will be the progeny of people who really wanted children. This is probably heritable and will probably stabilize birth rates.
Maybe. I think the difficulty is that in a place like Korea, the dependency ratio will become extremely high, and so taxes will have to go up sharply. Most voters will be retired and so will vote for the few young people to pay them. This will lead the young people to emigrate unless they’re prevented from doing so.
More like: "Every time someone stole from my car, that's because I forgot to lock the door, that the lock can be picked is not a problem".
Sure, a thief may pick your lock, but unless he knows there is something valuable in there, he will probably go find a car the owner forgot to lock, it less effort and there are plenty of them, or he may look for more valuable targets.
Just imagine a capable individual just like yourself, but with such a rotting core that they see the same devious plans you and I do, but lack the backbone/principles and moral/ethical fiber to prevent them from pursuing those ideas. Instead, they full endorse and selfishly benefit from them at the expense of others. With our large population, this individual, and many such like them are guaranteed to exist at all levels of the socio-economic ladder. Solipsism is the root of corruption continuing to sprout.
A golf ball hitting a bowling ball or basketball, both traveling at 30 units of speed can produce quite a fast golf ball. Not all of the debris will safely burn up.
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