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SpaceX lowering orbits of 4,400 Starlink satellites for safety's sake
- Jean-Papoulos 8mo agoFrom a comment : >The first move in the coming WWIII, where the emperors try to expand their empires militaril,y will be to wipe out any orbit with Starlink satellites. I find this highly unlikely, given Starlink is soon to reached 10k satellites and will continue to grow. Why expand 10 000 ballistic missiles to bring down one of many communications networks ?
- xxs 8mo ago[flagged]
- DrScientist 8mo agoIt's also been used for regime change attempts - part of the internet that's harder to shutdown, though apparently jamming GPS currently appears to be quite effective. https://www.independent.co.uk/news/world/middle-east/iran-internet-blackout-protest-starlink-musk-b2900101.html https://www.independent.co.uk/news/world/middle-east/iran-in...
- GuB-42 8mo agoWhat kind of pictures can starlink would take? When I look at pictures of starlink satellites, I don't see a camera. Maybe they have one, but if we can't see it, it is most likely useless for observation, except for taking pretty pictures of the Earth, or maybe other passing satellites. Spy satellites are more like space telescopes, but pointed at the Earth. As an example, Hubble is designed after a spy satellite, the "camera" is pretty massive and obvious. Starlink can probably be weaponized for a variety of thing, like for communication, obviously, but I don't think earth optical observation is one of them.
- NetMageSCW 8mo agoPerhaps Starlink can not (or wasn’t designed for it) but Starshield includes cameras and other sensors on some of its satellites.
- TOMDM 8mo agoBecause Kessler syndrome means you don't need to hit all 10k yourself. Lowering the orbits just means that we get back to normal faster, not that the it's impossible.
- lijok 8mo agoDoes Kessler syndrome also mean ICBMs become nonviable?
- Dylan16807 8mo agoNo. It's not a wall. The risk from going through a dangerous orbit is much much less than the risk from staying there.
- goku12 8mo agoThat depends on how you define risk. If it means the probability of a collision, then you'd be correct. But if a collision does happen, the consequences will be worse than being in the same orbit. Based on an oversimplified model, debris in orbit is likely to have low relative velocities with respect to an intact satellite in the same orbit, since a large deltav would change the orbit. (It's not as simple as this, but it's good enough in practice.) This is actually what asat weapons take advantage of. They usually don't even reach orbital velocity, just like ballistic missiles (of course, there are exceptions like the golden dome monstrosity). The kill vehicle just maneuvers itself into the path of the satellite and lets the satellite plough into it at hypervelocity.
- gpderetta 8mo agoI remember a short story about Canada preventing total global annihilation in WWIII, by deliberately triggering Kessler syndrome. My google-fu is failing me though.
- iberator 8mo agoI would love to read it:)
- bell-cot 8mo agoIf it's WWIII, and you're using ballistic missiles against satellite constellations, then either: - You are not targeting individual satellites; you're setting off nuclear warheads in space, and relying on the EMP to disable all satellites within a large radius of the blast - https://en.wikipedia.org/wiki/Nuclear_electromagnetic_pulse https://en.wikipedia.org/wiki/Nuclear_electromagnetic_pulse or - You're nuking the ground-based command & control centers for those satellites. Again, nothing like 10,000 missiles needed. (Or both.) To target 10,000 satellites directly, the "obvious" weapon would be a few satellite-launch rockets, lofting tons of BB's (or little steel bolts, or whatever) - which would become a sort of long-duration artillery barrage shrapnel in orbit.
- NetMageSCW 8mo agoThe BB idea doesn’t really work either- if they are in orbit they circle with the satellites and don’t hit anything, if they are at different speeds they are in different orbits and fly above and below the satellites and miss, if they cross the orbit SpaceX just moves the satellites to miss.
- bell-cot 8mo ago"Circle with the satellites" is not how orbits work. Do a Google image search for satellite ground tracks, and observe how those tracks repeatedly cross each other. In LEO, a 90 degree orbital crossing represents a relative velocity of >10km/s. (Normally, collisions do not happen because the satellites are under control, and everyone is making ongoing efforts to avoid collision. Kinda like how cars & trucks normally don't hit pedestrians.) BB's - https://www.amazon.com/bulk-bbs/s?k=bulk+bbs https://www.amazon.com/bulk-bbs/s?k=bulk+bbs - run roughly 3,000 to the kg. And are far too small to individually track in orbit - https://clasp.engin.umich.edu/2023/12/06/tracking-undetectable-space-junk/ https://clasp.engin.umich.edu/2023/12/06/tracking-undetectab... Bottom line - a "3 tons to LEO" satellite launch vehicle could put ~10,000,000 untrackable little metal objects into orbit, crossing satellite orbits at lethal velocities. Trivial methods, such as dispersing the BB's with small explosive charges, could randomize their individual orbits. The satellite operators have very good reason to be concerned about such "low tech" anti-satellite weapons.
- aucisson_masque 8mo agoYou don’t need 10k missiles. You need just one to blow up all of starlink satellites. This is like bowling, you hit one, it hits the other one etcétéras.
- jdiez17 8mo agoYou would likely need at least one per orbital plane, of which there are about 24.
- goku12 8mo agoBlowing up something in the same orbit as the targets isn't an effective strategy. The explosion disperses the fragments into different orbits that intersect the original orbit only at one or two points. And even if some of those fragments find their targets, the collision velocity will be low (relatively slow). It will be like getting hit with with shrapnels from a grenade. Depending on how they collide, the target may survive. If you think that grenade shrapnels are fast, you need to understand the 'hypervelocity impact' that happens when objects in different orbits collide, or when an interceptor hits a satellite. Hypervelocity impacts are impacts where the impactor moves faster than the speed of sound in the solid target. What that means in practice is that the debris/interceptor may have hit one end of the satellite and vaporized already, while the other end of the satellite doesn't yet feel the shock and vibration from that impact. That end doesn't yet know about the carnage that's about to hit it in a few milliseconds.
- gehwartzen 8mo agoI imagine you could just send a rocket to the specific orbit and just start metering out 100s of thousands of small steel (or whatever) BBs like seeding a yard; seeding a Kessler event. Something just a bit bigger than: https://en.wikipedia.org/wiki/Project_West_Ford https://en.wikipedia.org/wiki/Project_West_Ford
- NetMageSCW 8mo agoThat is not how it works at all. Imagine using a rocket and blowing up one car on a highway - how many other cars will actually be affected? How many cars on other highways will be affected?
- LightBug1 8mo agoWhat was that game on old PC's? ... Minesweeper ...
- tlb 8mo agoYou could launch some missiles, blow a few satellites into smithereens, and gradually over the next few months they would take out the others. That's a poor kind of war weapon. An effective weapon is one where you can inflict damage continuously, and are able to stop immediately upon some concession. If you can't offer to stop in return for concessions, you won't get any.
- panick21_ 8mo agoIts not really that easy, to cause such a chain reaction, specially if the other person reacts. And its also really expensive, each sat you take down costs you far more then what you hit. So unless you can actually cause a chain reaction its a losing proposition.
- RealityVoid 8mo agoYou don't take down satellites in order to force someone to negotiate, you take them down for denial of capabilities.
- ViewTrick1002 8mo agoNot really. That’s more science fiction than reality. You should try some Kerbal Space Program and explore how orbits are affected by thrust = collisions, in different directions. As soon as a satellite is hit the rest of the fleet can start thrusting and raise their orbits to create a clear separation to the debris field. Following such an attack the rest of the fleet would of course spread out across orbital heights and planes to minimize the potential damage done by each hit, leading to maximum cost for the adversary to do any damage. Rather than like today where the orbits are optimized for ease of management and highest possible bandwidth.
- ben_w 8mo agoLooking at the price of industrial lasers, right now the only thing stoping a random 3rd world terrorist cell from being able to afford to destroy all of them is the adaptive optics to compensate for atmospheric turbulence. Well, that and the fact that so much of the stuff on Amazon etc. that's listed as "welding laser" is actually a soldering iron.
- NetMageSCW 8mo agoI think you severely underestimate the amount of power you would need to damage some Starlink satellites in the 4 minutes they would be visible while tracking them at ridiculous speeds.
- ben_w 8mo agoModern welding lasers are pretty powerful. Hard part is focussing them, especially given need for adaptive optics for atmospheric turbulence. Movement is almost irrelevant, they only deviate from a fixed path while their engines run, and even then those engines are pretty weak. I'm saying the only real limit now is the adaptive optics.
- laughing_man 8mo agoWhen people attack satellites with lasers, what they're trying to do is blind surveillance sats. To actually physically damage a satellite would take enormous amounts of power and accurate tracking tied into powerful radars. That's something a state might do, but too many resources are involved for terrorists.
- impossiblefork 8mo agoI don't think that's necessarily true. I think with modern lasers the power to get permanent damage is there. I don't think powerful radars are required either. The satellites will probably reflect the laser. At 4000 km this is 26 ms, so you would probably be able to use the laser itself for the adjustments.
- ben_w 8mo ago
- Cthulhu_ 8mo agoOr why try to shoot them down when you can also go to the command center and turn them off? Or do a targeted strike on said command center. The sattelites are plentiful and redundant, but the network will collapse very quickly when they're no longer controlled from the surface. In fact, if SpaceX can no longer do any launches due to whatever reason, Starlink will no longer be feasible after a few year - if I'm reading it correctly, the sattelites have a lifetime of only 5 years, meaning they will have to continually renew them at a rate of 2000 new sattelites a year.
- aucisson_masque 8mo agoThere are so many satellites in orbit that there is a pretty good chance that if even one was to be hit by something and explode in many pieces, it would crash another one and then another one until there is nothing left. The nasa is pretty scared of it, so is SpaceX.
- fireflymetavrse 8mo agoThere is huge increase of orbital launches in recent years [1] done mostly by SpaceX and China is also planning to double its numbers in the coming years. The risks will be even higher. [1] https://spacestatsonline.com/launches/country https://spacestatsonline.com/launches/country
- goku12 8mo agoThat's the Kessler Syndrome. But it's better if it happens in a lower orbit, irrespective of what assets are present there. Space will be free for exploration again in a few years since all the debris there would eventually decay and deorbit. The article mentions a few months at 480 km. I'm a little skeptical about this figure though, because the last tracked piece from an NRO satellite that was shot down at ~250 km by SM-3 missile in operation burnt frost, lasted 20 months in space before reentry. SpaceX is probably using a statistical cutoff percentage of fragments to calculate the time. But all the pieces are dangerous uncontrolled hypervelocity projectiles. Spain lost a military communications satellite a few days ago from a collision with a tiny undetermined space debris.
- _factor 8mo agoTwo 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.
- tlb 8mo agoAt 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.
- choeger 8mo agoI think it's important to note that not all collisions are equally dangerous. Consider a sat on a polar orbit colliding with one on a equatorial orbit. Or two satellites on different directions. That is going to be spectacular. Otoh, these kind of collisions are unlikely and should be manageable by just assigning certain shells (say 5km) for every possible direction and orientation. If two Starlink satellites collide that go roughly in the same direction, it's not exactly a huge problem. I think the biggest issue is to coordinate this and potentially disallow some excentric orbits.
- bell-cot 8mo agoNot quite how it works, unfortunately. Once you've got even hundreds of satellites in non-equatorial orbits, trying to provide global coverage - their ground tracks very frequently cross each other. Even if they're all at the same orbital inclination. While those mostly won't be 90 degree crossings - the great majority will involve several km/s relative velocity. And you'd run out of (say) 5km LEO shells very quickly.
- kbelder 8mo agoBut the orbit is a minimum of about 50,000 kilometers, and the satellite is maybe a meter across. That's a very low probability of a collision per crossing. I get that 'probably safe' or '0.001% chance of destruction per day' is not very satisfying for an investment that cost millions, but everything always comes down to odds. None of these satellites are eternal, even if they're the only thing in their orbit.
- direwolf20 8mo agoIs it still a small number when multiplied by the square of the number of satellites and the number of times they orbit each day?
- kbelder 8mo agoDon't know. But I'm sure that people at NASA and other such places have done that calculation. I just wanted to point out that orbital space is big, so you have to do the math to see if there's an actual problem.
- nelox 8mo agoWhat’s the plan as the solar maximum returns?
- thegrim000 8mo agoAdjust them again as needed ..
- yanis_t 8mo agoCan anyone explain how does one technically lower a satellite?
- frumiousirc 8mo agoEject mass in the forward direction of its current tangent of motion. Slow down to go down.
- pandemic_region 8mo agoSo, for this they have a bit of expendable extra mass on board? What material is it, would it not cause even more debris then?
- alecco 8mo agohttps://starlink.com/technology https://starlink.com/technology > Efficient argon thrusters enable Starlink satellites to orbit raise, maneuver in space, and deorbit at the end of their useful life. Starlink is the first argon propelled spacecraft ever flown in space. And you can see "How Ion Engines Work in Under 60 Seconds" https://www.youtube.com/shorts/_MUv28Yf_4g https://www.youtube.com/shorts/_MUv28Yf_4g
- goku12 8mo agoThe 'expendable mass' is almost never a solid or liquid. It's the gaseous combustion exhaust or plasma exhaust from the satellite's thrusters. The advantage of gases is that they just expand and disperse fast enough to be too wispy to cause anything on impact. However, there are a few systems that do use solid masses for obtaining a reaction force. A remarkable example is called a 'Yo-yo despinner' [1]. It was used in missions like Phoenix (Mars mission) and Dawn (Asteroid belt proto-planet mission). And yes, it does create space debris. But those space debris are probably somewhere in orbit around the sun. Nothing that those guys are going to be too worried about. [1] https://en.wikipedia.org/wiki/Yo-yo_de-spin https://en.wikipedia.org/wiki/Yo-yo_de-spin
- laughing_man 8mo ago
- ChrisArchitect 8mo ago3 week old news OP? Previously: https://news.ycombinator.com/item?id=46457454 https://news.ycombinator.com/item?id=46457454
- benabbott 8mo agoWon't this make running Starlink more expensive? Lower orbits > Increased atmospheric drag > More fuel expended to maintain orbit > Heavier sats due to more fuel > Increased launch cost per unit Or even: Lower orbits > Increased atmospheric drag > Quicker orbit decay > Shorter lifespan of sats > More frequent launches Forgive my Kerbal-based space knowledge here.
- foxyv 8mo agoEssentially, the atmosphere contracted due to the solar minimum and they want to make sure inoperative satellites decay within months rather than years. Ballistic decay is a safety mechanism in case their satellites break down. Also they will use less fuel for avoiding the crowded 550km band. > "As solar mininum approaches, atmospheric density decreases, which means the ballistic decay time at any given altitude increases — lowering will mean a >80% reduction in ballistic decay time in solar minimum, or 4+ years reduced to a few months," Nicolls wrote in his X post. "Correspondingly, the number of debris objects and planned satellite constellations is significantly lower below 500 km, reducing the aggregate likelihood of collision."