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SpaceX punched a hole in the ionosphere

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Re: SpaceX punched a hole in the ionosphere

#41

Post by elwell »

wyldfire wrote: post #13
panick21_ wrote: post #9

Earlier quoted context omitted.

The waste, waste majority of sats never turn into space debris. Every single sat that launches today in the West has a deorbit planned. The only sat that turn into space debris will be those that brake unexpectitly and totally unrecoverable. And the Starlink sats are so low that they dont really turn very meaningful debris ever. And in general, yes LEO can handle millions of sats. We have like 150k cars in a single t…

Freudian slip.

It's just phonetically in a german accent.

Re: SpaceX punched a hole in the ionosphere

#42

Post by tamimio »

jrockway wrote: post #37
tamimio wrote: post #24

> Sudden GPS errors can also result from the anomalies. When we fly drones especially BVLOS operations we sometimes encounter some GNSS anomalies, that in some cases we just cancel the mission that day and the next day it’s with no issues. Could it be that’s the reason? Who knows, but it might be an issue later with crewed drones.

If you have a dual frequency receiver (L1/L2), then the ionospheric error is corrected for. These are very common these days, so probably not the reason.

We had similar anomalies with tri-bands gnss drone before (L1, L2, and L5) with multi constellations support, I even remember before we had similar issues with an RTK enabled system. It is puzzling because the next day we would bring the sane drone and systems, and as of nothing happened, and since the problem solve itself we never bothered to investigate more.

Re: SpaceX punched a hole in the ionosphere

#43

Post by 3cats-in-a-coat »

simple-thoughts wrote: post #20
3cats-in-a-coat wrote: post #14

Earlier quoted context omitted.

Cars don’t constantly move thousands miles an hour uncontrollably

Cars also don’t move in easily predicted patterns for decades without turning from their predetermined path.

They do. We call those paths roads.

Re: SpaceX punched a hole in the ionosphere

#44

Post by dfox »

tamimio wrote: post #24

> Sudden GPS errors can also result from the anomalies. When we fly drones especially BVLOS operations we sometimes encounter some GNSS anomalies, that in some cases we just cancel the mission that day and the next day it’s with no issues. Could it be that’s the reason? Who knows, but it might be an issue later with crewed drones.

That depends of what exactly is that anomaly. If your GNSS receiver tracks 4 satellites from the same constellation then obviously, this kind of ionosphere anomaly will with some probability lead to some kind of unexpected fix error (but with some high probability still smaller than the specified error of such receiver). I believe that typical somewhat modern multi-constellation GNSS receiver will either consider satellites affected by that as invalid outliers or just average that out.

Re: SpaceX punched a hole in the ionosphere

#45

Post by panick21_ »

mabbo wrote: post #22
simple-thoughts wrote: post #20

Earlier quoted context omitted.

Cars also don’t move in easily predicted patterns for decades without turning from their predetermined path.

They sort of do though. Cars, for the most part, follow the road and the direction they're already going. They (usually) signal if they're about to make changes. And to be safe, we've built an arrangement that they only travel on these specific paths at specific speeds, modifying their speed to match the other cars they might hit. The challenge with satellites is that steering is hard and very limited. And they don't…

It is well known that potential points of conflict are a huge issue. That's why a round about is safer then intersection.

> And to be safe

Tell that to the 40k people killed and the millions hurt by cars in the US alone.

Cars constantly turn and intersect routes with other cars without any planning, even if perfectly handled and most of time they are not.

> The challenge with satellites is that steering is hard and very limited. And they don't have brakes they can slam to come to a stop if they need to suddenly avoid a collision.

They don't need to break, they just need to know the position of speed of other objects and correct position ahead of time.

The only reason why this is even a program at all is because only the US has even minimally invested in monitoring. If each nation just did the same our accuracy would be far, far higher and things would be way better.

So, as of now, we have minimally invested in solving this problem and it isn't a big issue. Slightly more investment (that is justified if we 10-100-1000x the amount of sats) is required eventually.

But compared to what it takes to make cars not crash into each other its nothing.

(Unless its like US infrastructure design that seems to want to make cars crash into things, but I hope in Space we can avoid that)

Re: SpaceX punched a hole in the ionosphere

#47

Post by starbase »

mabbo wrote: post #22
simple-thoughts wrote: post #20

Earlier quoted context omitted.

Cars also don’t move in easily predicted patterns for decades without turning from their predetermined path.

They sort of do though. Cars, for the most part, follow the road and the direction they're already going. They (usually) signal if they're about to make changes. And to be safe, we've built an arrangement that they only travel on these specific paths at specific speeds, modifying their speed to match the other cars they might hit. The challenge with satellites is that steering is hard and very limited. And they don't…

Cool thing about satellites is if you're on the same path, you must also be going the same speed.

Collision avoidance in LEO is quite elegant. When two satellites are predicted to pass uncomfortably close to one another, one satellite will fire its station keeping thrusters to raise its orbit above the other. No brakes or swerving needed, just a slight push well ahead of time. Starlink sats do this over 1000 times per week.

Even better, energy used for avoidance reduces energy needed for station keeping on a 1:1 basis. Avoidance maneuvers are effectively free.

Re: SpaceX punched a hole in the ionosphere

#48

Post by coldtea »

Jeff_Brown wrote: post #35
arbuge wrote: post #23

Earlier quoted context omitted.

> One famous example occured on August 25, 2017, when a Falcon 9 rocket carrying Taiwan’s FORMOSAT-5 satellite created a hole four times bigger than the state of California. Doesn't sound too local to me.

Good point. Deserves some numbers. California's area is about 500 thousand km^2, and the Earth's is about 500 million, which means the side facing the Sun is about 250 million, so we're talking about 0.2% of the area facing the sun. Suppose the hole takes six hours to heal (the article makes it sound like it takes much less), and suppose there's a launch every month (since launches have in the past carried 600 satell…

>so we're talking about 0.2% of the area facing the sun

Doesn't sound small at all.

Re: SpaceX punched a hole in the ionosphere

#49

Post by macksd »

chinchilla2020 wrote: post #32
op00to wrote: post #19

Earlier quoted context omitted.

What about high frequency trading shops?

This is talking about radio wave frequency, not trading frequency.

The funny thing is that in most ham radio usage, the "high frequency bands" are actually about as low a frequency as most people will ever use. I don't think I've come across anything about low and medium frequencies except in reference materials. People generally use "high frequency", "very high frequency", or "ultra high frequency".

Re: SpaceX punched a hole in the ionosphere

#50

Post by b33j0r »

ghaff wrote: post #31
b33j0r wrote: post #26

Earlier quoted context omitted.

LEO is big, but only a few orbits are desirable and all circular orbits at the same altitude cross twice, by definition. It’s like slot cars, but much lower probability of an “intersection event.” That’s fun! Of course, we do already have something analogous to FAA altitude separations. But that requires everyone everywhere to cooperate in real-time, and mandates some degree of maneuverability. I guess orbital decay…

You also have people who would largely prioritize for astronomical observations over rural internet—perhaps because they think people should be living in cities anyway. I’m only being mildly sarcastic.

The needs of the many outweigh the needs of the few.

(They can just be awfully hard to count, no matter who counts.)

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