Starlink Thread (split from SpaceX)

[kerbiloid]

There should be an international anti-monopoly law against orbit squatting.

4 minutes ago, Rakaydos said:

You could really use better labels, but it appears you assume every satellite must have it's own "orbital torus"

No. I count only orbital torus of the victim craft.
The Starlink sats are presumed to be uniformly distributed.

4 minutes ago, Rakaydos said:

You could really use better labels

Feel free to suggest better ones.

Edited September 3, 2019 by kerbiloid

[Rakaydos]

Just now, kerbiloid said:

There should be an international anti-monopoly law against orbit squatting.

No. I count only orbit torus of the victim craft.
The Starlink sats arre presumed uniformly distributed.

Feel free to suggest better ones.

Can you clarify what you mean by "uniformly distributed?" we know exactly what their orbital positions are going to be, it's in the paperwork, and so will all other satellite operators.

[kerbiloid]

4 minutes ago, Rakaydos said:

Can you clarify what you mean by "uniformly distributed?"

A spherical layer from R1 ro R2.
For the lowest orbits R1~ Rearth + 335 km, R2~ Rearth + 345 km
I take 20 km as the layer radial thickness, as they have described 3 orbit "shells" inside this layer at 5 km from each other.

Starlink satellites are uniformly distributed in this space. There is about 1.5 mln km³ per sat inside this volume.

4 minutes ago, Rakaydos said:

we know exactly what their orbital positions are going to be

We don't at the moment, but that doesn't matter as their relative positions are permanently changing.
So, for any crossing trajectory we can treat them as a uniform cloud of particles.

Edited September 3, 2019 by kerbiloid

[Rakaydos]

1 minute ago, kerbiloid said:

A spherical layer from R1 ro R2.
For the lowest orbits R1~ Rearth + 335 km, R2~ Rearth + 345 km
I take 20 km as the layer radial thickness.

Starlink satellites are uniformly distributed in this space. There is about 1.5 mln km³ per sat inside this volume.

We don't at the moment, but that doesn't matter as their relative positions are permanently changing.
So, for any crossing trajectory we can treat them as a uniform cloud of particles.

If what you claim were true, the ESA would have a dead satellite right now.

So why is the ESA sat alive?

[kerbiloid]

Just now, Rakaydos said:

If what you claim were true, the ESA would have a dead satellite right now.

So why is the ESA sat alive?

Does Starlink exist?

[Rakaydos]

3 minutes ago, kerbiloid said:

Does Starlink exist?

Yes. The ESA dodged one of their sats, like we have been saying. Whats so hard to understand about this?

[kerbiloid]

5 minutes ago, Rakaydos said:

Yes. The ESA dodged one of their sats, like we have been saying. Whats so hard to understand about this?

So, they will be doing this 200 times more often when 12 000 Starlinks sat instead of 60.

P.S.
In fact, the project looks just like a permanent job for Space-X Falcons.
Probably several tens launches per year to replace dead sats. Not to upgrade the network, but to keep it from falling!
And try to stop funding.
I would buy that for a dollar RUR equivalent of USD according to the current rate.

Edited September 3, 2019 by kerbiloid

[Rakaydos]

2 minutes ago, kerbiloid said:

So, they will be doing this 200 times more often when 12 000 Starlinks sat instead of 60.

 

It's not hard- the only reason it was newsworthy was because the ESA's email ended up in the SpaceX spam folder, and proper synchronization will mean it will never happen again.

Quote

Probably several tens launches per year to replace dead sats. Not to upgrade the network, but to keep it from falling!

But, you know, ALSO upgrading the network while they're replacing it. Not relying on 30 year old tech that absolutely cannot afford to fail with 30 years of operation without maintenance, the way our current sats work.

But you're right, it's a bit expensive for the Falcon 9 fleet to maintain. Better upgrade to Starship!

[kerbiloid]

3 minutes ago, Rakaydos said:

But you're right, it's a bit expensive for the Falcon 9 fleet to maintain. Better upgrade to Starship!

Starship is fine, too.
Block the only road, then take money from the travellers for passage, to keep the minefield intact.

***
So,  LEO will be a space full of permanently maneuvering sats in unpredictable orbits.

Edited September 3, 2019 by kerbiloid

[Rakaydos]

2 minutes ago, kerbiloid said:

Starship is fine, too.
Block the only road, then take money from the travellers for passage, to keep the minefield intact.

***
So,  LEO will be a space full of permanently maneuvering sats in unpredictable orbits.

What's unpredicatable about a 1m/s course change after a week of discussion over email?

[CatastrophicFailure]

3 minutes ago, kerbiloid said:

Starship is fine, too.
Block the only road, then take money from the travellers for passage, to keep the minefield intact.

***
So,  LEO will be a space full of permanently maneuvering sats in unpredictable orbits.

Not at all, eventually they’ll all just clump together and can be moved out of the way with a gentle push...

[kerbiloid]

8 minutes ago, Rakaydos said:

What's unpredicatable about a 1m/s course change after a week of discussion over email?

Why didn't they do that in this case, when there is only 60 sats, not 12 000?

Edited September 3, 2019 by kerbiloid

[Rakaydos]

3 minutes ago, kerbiloid said:

Why didn't they do that in this case, when there is only 60 sats, not 12 000?

...

They -did- do it in this case.

...next question.

Edited September 3, 2019 by Rakaydos

[kerbiloid]

1 minute ago, Rakaydos said:

...next question.

Are you aware of Combinatorial Explosion term? What emails? Only automatic evasion.

[Rakaydos]

3 hours ago, tater said:

 

The emails that were caught in the spaceX spam folder, and still avoided the collision.

[Terwin]

30 minutes ago, kerbiloid said:

A spherical layer from R1 ro R2.
For the lowest orbits R1~ Rearth + 335 km, R2~ Rearth + 345 km
I take 20 km as the layer radial thickness, as they have described 3 orbit "shells" inside this layer at 5 km from each other.

Starlink satellites are uniformly distributed in this space. There is about 1.5 mln km³ per sat inside this volume.

That is sort of like saying that walking in a park has he same odds of being hit by a vehicle as walking across an interstate.

In this scenario SpaceX has 60 satellites 'driving' down each of ~200 well-known roads with a well known spacing, so that anyone who wants to cross those roads can plan months in advance and know exactly when it will be clear.  Or they can use the pedestrian bridges(aka different orbital altitude) and never even touch the roads in question.

 

I believe the process is, that whoever launches first has the right of way, and as anyone who launches later knows exactly where your satellite will be, so they are responsible for avoiding it(which is why SpaceX was supposed to avoid the ESA satellite and not the other way around).  Unless you are experimenting with aerobraking(like SpaceX is with those 3 starlinks), you should be able to calculate any potential collisions days in advance, and easily avoid it with just a couple m/s at the right time.

 

[kerbiloid]

1 minute ago, Terwin said:

That is sort of like saying that walking in a park has he same odds of being hit by a vehicle as walking across an interstate.

Poetry is nice, but what about numbers?

2 minutes ago, Terwin said:

In this scenario SpaceX has 60 satellites

12 000, and they don't driving down, they fill the space.

+ OneWab ones is madness is contagious.

[Rakaydos]

Just now, kerbiloid said:

12 000, and they don't driving down, they fill the space.

Clearly you didn't actually read the comment you were replying to.

Nor do you have any sense of scale if you think even 12,000 sats in a single orbit "fill the plane." 

[kerbiloid]

3 minutes ago, Rakaydos said:

Nor do you have any sense of scale if you think even 12,000 sats in a single orbit "fill the plane." 

I don't think, I have calculated, and see no opposite calculations.

[Rakaydos]

11 minutes ago, kerbiloid said:

I don't think, I have calculated, and see no opposite calculations.

Then you are blind.

Let me go over this again, one more time.

The circumference of the earth is over 40,000 km. We'll use this as an approximation of the hoop of our orbital path, which is even longer, because it's not at earth's surface.

Lets assume all 12,000 sats are in the same orbit. They arnt, but lets assume they are, just to show how ridiculus your claim is.

The sats all fit in a city bus-sized fairing. Lets be generous and call each satelite 3m by 1.5m. The solar panel folds out in the short direction about 5 times, so lets call the whole sat 3mx9m 

So we've got 12,000 satelites in 40,000 km. That's 3 satelites every 10 km, or about a sat every 2 miles. Each sat is nowhere near 2 miles long. To bring back the traffic analogy, there's plentry of room to merge with the freeway traffic.

Edited September 3, 2019 by Rakaydos

[tater]

Starlink is supposed to have (just the first few thousand?) in 24 planes, BTW. some are at 1100 km, too, so it's nothing like 12k in one plane, so maybe more like 1 every 240 km in a plane.

 

[Rakaydos]

1 minute ago, tater said:

Starlink is supposed to have (just the first few thousand?) in 24 planes, BTW. some are at 1100 km, too, so it's nothing like 12k in one plane, so maybe more like 1 every 240 km in a plane.

 

with how out of touch with reality Kerboiloid seems to be, I really wanted to drive the point home.

[Elthy]

@kerbiloid: Lets go with your numbers of one collision in every 80000 orbits in the lower layers. As an orbit takes about 90min thats over 13 years per necessary course correction of a single star link satellite (the one that would have collided). So for evey other sat in that layer one starlink sat (out of the whole constellation) has to do a course correction every 13 years, the others none at all. This is an incredibly low number!

Actually its way to low since orbital paths arent measured precisely, so they will maneuver even with a low chance of a collision, ESA states over 1/10000 as the limit. This would result in a course correction every 12h for one of all SpaceX sats in the layer (about 7500) -> Each one has to do a correction about every 10 years for every other sat in the same layer.

There isnt much flying around that low other than other planned mega constellations, which will propably coordinate with SpaceX, reducing the collision chance (and thus need for maneuver) drasticaly.

[mikegarrison]

9 minutes ago, Elthy said:

@kerbiloid: Lets go with your numbers of one collision in every 80000 orbits in the lower layers. As an orbit takes about 90min thats over 13 years per necessary course correction of a single star link satellite (the one that would have collided). So for evey other sat in that layer one starlink sat (out of the whole constellation) has to do a course correction every 13 years, the others none at all. This is an incredibly low number!

I'm not sure you are making the point you think you are making. Even if any individual Starlink satellite only has to adjust orbits every 13 years, that would still be about 1000 adjustments a year for the entire constellation. Three per day. One every 8 hours.

Edited September 3, 2019 by mikegarrison

[Elthy]

No, you are missunderstanding me (its hard to write that correctly). In this scenario, one sat had to move after 13 years to avoid a collision, the others can remain stationary. After about another 13 years another maneuver would be neccessary, propably by a different sat. If there is an imminent collision, only the affected sat has to move, not the whole constellation.