3 ms·
> In the long term, this accumulation of junk may lead to a chain reaction, known as Kessler syndrome, that would make some low-Earth orbits unusable. I read a
by gchamonlive 6y ago
> In the long term, this accumulation of junk may lead to a chain reaction, known as Kessler syndrome, that would make some low-Earth orbits unusable.
I read about it, and it seems a little counter-intuitive for me. I would expect that in a collision in space, some of the kinetic energy would be used in internal structural changes, and not all converted to the resulting motion.
Am I wrong here? If not, does it still preserve enough kinetic energy after collision to promote this chain reaction? And how long until lower space ring is actually unusable?
- copperwater69 6y agoImagine two objects hitting each other perpendicularly, as opposed to head on. Plenty of momentum could be conserved and thrown out in a median vector. Edit: Not only that, but even if 90% of momentum was lost - it only takes another satellite going in the opposite direction to supply all the energy. Here's what 2 ounces of plastic does at 15,000mph to a block of aluminium. https://imgur.com/gallery/8NwAhgK https://imgur.com/gallery/8NwAhgK
- hiharryhere 6y ago1/2 an ounce (14 grams) according to that link. Even more nuts!
- gchamonlive 6y agoIt depends on the material. If they are flexible, and deform easily, a lot of energy would be converted into structural damage, I would presume. > it only takes another satellite going in the opposite direction to supply all the energy I see, indeed the next collision will supply a lot of external momentum.
- MauranKilom 6y ago> It depends on the material. If they are flexible, and deform easily, a lot of energy would be converted into structural damage, I would presume. At those speeds, everything is "flexible" in the sense that even metal just flows in a fluid-like manner (see picture linked in the comment). Also, the material would have to somehow convert the energy of an entire car crashing into it at full speed. Except the car is only an inch wide.
- Tuna-Fish 6y agoMaterial properties essentially become completely irrelevant when things hit into other things at speeds that greatly exceed the speed of sound in either material. At that point, you get best results if you just model both objects as fluids.
- gchamonlive 6y agointeresting insight! thanks
- marsokod 6y agoYou are right that the collisions will dissipate some of the mechanical energy will be dissipated into heat and technically collisions will reduce the duration it takes for the mass of debris that are in orbit. I am not sure if that has a significant impact on top of the atmospheric drag though. However, the Kessler syndrome is not about the total mass of debris in orbit, but the number of individual debris. So while before the collision we had 2 nicely aggregated debris, after the collision you will have thousands of small ones. The small ones will tend to deorbit faster on average, because of the loss of energy mentioned above and also because their aggregated surface area increases, but you still have more debris. And when we are talking about multiple decades/centuries of lifetime, these debris will collide with other satellites, creating a positive feedback loop, increasing the numbers of debris exponentially, at least initially. Obviously this is just the beginning of the process, which will end up with a maximum number of debris and then a decrease towards zero, but that timeline is extremely long and therefore not really relevant to us.
- gchamonlive 6y agoI see, thanks for taking the time to answer me =D