Author Topic: Starlink : General Discussion - Thread 2  (Read 1077170 times)

Offline Rondaz

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Re: Starlink : General Discussion - Thread 2
« Reply #1320 on: 04/18/2020 01:58 pm »
Particularly interesting is elevation angles down to 25 degrees (which SpaceX admitted would need mechanically steered user terminals). Also no mention whatsoever of crosslinks now being part of the implementation plan...

https://twitter.com/TMFAssociates/status/1251373364582612992

Offline RedLineTrain

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Re: Starlink : General Discussion - Thread 2
« Reply #1321 on: 04/18/2020 02:27 pm »
The gateway map: https://www.google.com/maps/d/viewer?mid=1H1x8jZs8vfjy60TvKgpbYs_grargieVw&ll=30.479815690358823%2C-70.95175456250001&z=3
shows most of Mexico covered, and southern Canada as well. Whilst covering Mexico may be "incidental" due to Gateways in BC etc, covering Canada is "surely" imo intentional as Gateways are placed close to the Canadian Border. Elon is a Canadian Citizen, lived there, and has family links there. There must imo be an intention to roll out the service to Canada with or soon after the US.

Nice map.  Shows fairly even spread across the United States, assuming that the uncovered areas will be filled in.  Maybe 50 total gateways for the U.S. in this phase.

Offline Nomadd

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Re: Starlink : General Discussion - Thread 2
« Reply #1322 on: 04/18/2020 04:29 pm »
Has there been anything about the rest of the world? Will they probably stick to the U.S./Canada until the laser links come on line, or are they planning ground stations outside North America? (This from the person who complains about people too lazy to read the whole thread)
Actually, I realize that's kind of a dumb question. If they want to keep latency low, they'll still need ground stations all over the place. Laser links don't help much if Germany has to talk to Austria via New York.
 I've been into a Cisco or two, but routing through thousands of points zipping all over the planet at 15,000 mph is going to be interesting. Maybe more challenging that building the hardware.
 Is there any possibility they're going to do user to user without going through a gateway once the intersat links are up?

 El Paso looks a little iffy in that map.
https://www.google.com/maps/d/viewer?mid=1H1x8jZs8vfjy60TvKgpbYs_grargieVw&ll=30.479815690358823%2C-70.95175456250001&z=3
« Last Edit: 04/18/2020 04:45 pm by Nomadd »
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Offline Nomadd

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Re: Starlink : General Discussion - Thread 2
« Reply #1323 on: 04/18/2020 04:59 pm »
  I'm waiting for the "SpaceX slashes the number of satellites in their proposed Starlink system" headlines.
 They went from 4409 to 4408 in the proposed modification.
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Re: Starlink : General Discussion - Thread 2
« Reply #1324 on: 04/18/2020 05:01 pm »
Has there been anything about the rest of the world? Will they probably stick to the U.S./Canada until the laser links come on line, or are they planning ground stations outside North America? (This from the person who complains about people too lazy to read the whole thread)
Actually, I realize that's kind of a dumb question. If they want to keep latency low, they'll still need ground stations all over the place. Laser links don't help much if Germany has to talk to Austria via New York.
 I've been into a Cisco or two, but routing through thousands of points zipping all over the planet at 15,000 mph is going to be interesting. Maybe more challenging that building the hardware.
 Is there any possibility they're going to do user to user without going through a gateway once the intersat links are up?

As you say the interesting problem is the routeing, not the only interesting one of course. 
It's been discussed elsewhere the shortest routes may be ISL' s or ground bounces, I can see the military would like the user to user capability. 

Offline philw1776

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Re: Starlink : General Discussion - Thread 2
« Reply #1325 on: 04/18/2020 05:08 pm »
Has there been anything about the rest of the world? Will they probably stick to the U.S./Canada until the laser links come on line, or are they planning ground stations outside North America? (This from the person who complains about people too lazy to read the whole thread)
Actually, I realize that's kind of a dumb question. If they want to keep latency low, they'll still need ground stations all over the place. Laser links don't help much if Germany has to talk to Austria via New York.
 I've been into a Cisco or two, but routing through thousands of points zipping all over the planet at 15,000 mph is going to be interesting. Maybe more challenging that building the hardware.
 Is there any possibility they're going to do user to user without going through a gateway once the intersat links are up?

As you say the interesting problem is the routeing, not the only interesting one of course. 
It's been discussed elsewhere the shortest routes may be ISL' s or ground bounces, I can see the military would like the user to user capability.

My take on this is that Elon/Gwynne is waiting for military funding to develop & deploy a military requirements constellation with laser inter-satelite communication.  Could even be already development funded with black budget money.
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Offline soltasto

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Re: Starlink : General Discussion - Thread 2
« Reply #1326 on: 04/18/2020 06:05 pm »
Particularly interesting is elevation angles down to 25 degrees (which SpaceX admitted would need mechanically steered user terminals). Also no mention whatsoever of crosslinks now being part of the implementation plan...

https://twitter.com/TMFAssociates/status/1251373364582612992

He's making a lot of assumptions that in my opinion are flawed and he quite clearly has a bias against SpaceX, so I would take his comments just as opinion and not as news.

There is no reason what so every to believe that the user terminals will be mechanically steered during operation.
Actually, it doesn't make any sense what so ever to have a mechanically steered phased array antenna other than giving it a bias for latitudes > 53 to extend coverage as fare as possible.

Offline lonestriker

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Re: Starlink : General Discussion - Thread 2
« Reply #1327 on: 04/18/2020 06:41 pm »

He's making a lot of assumptions that in my opinion are flawed and he quite clearly has a bias against SpaceX, so I would take his comments just as opinion and not as news.

There is no reason what so every to believe that the user terminals will be mechanically steered during operation.
Actually, it doesn't make any sense what so ever to have a mechanically steered phased array antenna other than giving it a bias for latitudes > 53 to extend coverage as fare as possible.

Are the ISL laser links even regulated by the FCC? Firing light beams between satellites wouldn't generate any meaningful interference of any kind.  Even if the ISLs are not going live until later revisions of Starlink, it's not as though that in and of itself makes Starlink unsuited for satellite internet access in general.  You may not get coverage over large bodies of water/land without downlinks in range, but SpaceX will be busy onboarding people in rural area or large customers like the US military for quite some time.

Offline Roy_H

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Re: Starlink : General Discussion - Thread 2
« Reply #1328 on: 04/18/2020 07:51 pm »
My take on this is that Elon/Gwynne is waiting for military funding to develop & deploy a military requirements constellation with laser inter-satelite communication.  Could even be already development funded with black budget money.

I don't believe funding is that big an issue. Sure, SpaceX will take advantage of any funding available, but they are committed to progressing as fast as they can and will implement ISC asap. Once ISC in in place I see no reason that there wouldn't be cases for user to user comms without going through a gateway.
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Re: Starlink : General Discussion - Thread 2
« Reply #1329 on: 04/18/2020 07:55 pm »
After this next launch (6) SpaceX will have a minimum for an operational network with U.S. coverage. 
I think Alaska/Canada, 70 deg., with 3 launches will be next. 
What will after that? 

Offline DistantTemple

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Re: Starlink : General Discussion - Thread 2
« Reply #1330 on: 04/18/2020 08:42 pm »

He's making a lot of assumptions that in my opinion are flawed and he quite clearly has a bias against SpaceX, so I would take his comments just as opinion and not as news.

There is no reason what so every to believe that the user terminals will be mechanically steered during operation.
Actually, it doesn't make any sense what so ever to have a mechanically steered phased array antenna other than giving it a bias for latitudes > 53 to extend coverage as fare as possible.

Are the ISL laser links even regulated by the FCC? Firing light beams between satellites wouldn't generate any meaningful interference of any kind.  Even if the ISLs are not going live until later revisions of Starlink, it's not as though that in and of itself makes Starlink unsuited for satellite internet access in general.  You may not get coverage over large bodies of water/land without downlinks in range, but SpaceX will be busy onboarding people in rural area or large customers like the US military for quite some time.
I thought that the inter-sat laset links were a technical problem.

However a different problem, is one we've previously thought of as a benefit - making an alternative internet backbone, with low latency traffic across the world.

The problem is that traffic is screened and metadata stored at the border in the US. This is possible because of cooperation between operators and government allows placement of equipment, and physical access to the routers and fibre.

Starlink would not be able to provide physical ground side locations for such monitoring, and new methods of monitoring communication in and out of the US for the ISL traffic would have to be developed. SpaceX may not be happy with either the ethics, or the logistics and cost of implementing such systems, or developing them is a long pole. In the UK ISP's (internet service providers) also have to keep certain metadata, and logs etc on users. Traffic is routed through the ISP, who has to invest in systems to meet this obligation.
If all Starlink traffic has to go through base stations, then those locations can be used to meet such legal requirements, and/or being within the USA Starlink will not be the agent importing and exporting communications, so will not have the burden of all these "monitoring" processes.

Such arrangements may have national security classifications, so planning is unlikely to be visible in publicly released documents. If such planning is underway, an expectation of it taking a few years, may be a reason SX can take its time to develop ISL technology whilst they await outcomes/instructions.

OK lots of speculation.... but I believe valid.
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Offline philw1776

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Re: Starlink : General Discussion - Thread 2
« Reply #1331 on: 04/18/2020 08:50 pm »
My take on this is that Elon/Gwynne is waiting for military funding to develop & deploy a military requirements constellation with laser inter-satelite communication.  Could even be already development funded with black budget money.

I don't believe funding is that big an issue. Sure, SpaceX will take advantage of any funding available, but they are committed to progressing as fast as they can and will implement ISC asap. Once ISC in in place I see no reason that there wouldn't be cases for user to user comms without going through a gateway.

I think cash flow is a big issue at SpaceX given everything they are doing at once.
They have a long history of obtaining govt funding to move R&D (in this case inter-satellite laser comms - NOT trivial)
For example, they secured ~$60 million in Air Force funds for development of a methane-oxygen propellant upper stage, which was really Raptor funding.
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Offline gongora

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Re: Starlink : General Discussion - Thread 2
« Reply #1332 on: 04/18/2020 09:30 pm »
After this next launch (6) SpaceX will have a minimum for an operational network with U.S. coverage. 
I think Alaska/Canada, 70 deg., with 3 launches will be next. 
What will after that?

Six launches was for Northern US. Another six for Southern US. Then the rest of the 1500 sat initial deployment. After that it will be interesting to see which inclination they do next.

Offline DistantTemple

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Re: Starlink : General Discussion - Thread 2
« Reply #1333 on: 04/18/2020 09:54 pm »
After this next launch (6) SpaceX will have a minimum for an operational network with U.S. coverage. 
I think Alaska/Canada, 70 deg., with 3 launches will be next. 
What will after that?

Six launches was for Northern US. Another six for Southern US. Then the rest of the 1500 sat initial deployment. After that it will be interesting to see which inclination they do next.
After reading the "Narrative Application" in the current filing, I suspect there may be more changes in their launch methodology. I assume you are quoting from sources prior to this filing, and the knowledge that these orbits are lowering and changing inclination.

One obvious point is that all these "constellations" are now at about the same height, and both the 70 degree and 97.6 degree planes could immediately contribute to the coverage over the southern USA, and not only be of significant utility further North in Canada and Alaska etc.

Money for connecting remote citizen in Alaska etc (I forgot the programme name) is still in contention. Maybe SX intends to "create facts on the ground" by actually demonstrating high bandwidth, low latency to remote locations (including voice ;-) ) Before final decisions are made, even the current filing is more evidence of their intent and method.

I suspect there is a change in launch order to do just that: populate 3 planes of 20 sats each at 70 degrees inclination, and test some ground stations, possibly in his uncle's farm where he worked, the remote Alaskan base where they do Tesla snow testing... etc and maybe some remote research station. Will we see starlink terminals on "Ice Road Truckers"?  Playing first person shooters in 4K whilst sheltering from bears up a tree! Plenty of things to tweet about!
« Last Edit: 04/18/2020 09:57 pm by DistantTemple »
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Offline Hummy

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Re: Starlink : General Discussion - Thread 2
« Reply #1334 on: 04/18/2020 10:20 pm »
After this next launch (6) SpaceX will have a minimum for an operational network with U.S. coverage. 
I think Alaska/Canada, 70 deg., with 3 launches will be next. 
What will after that?

The new modification will take 6-9 months to get approved. I believe L7.1 will target the plane where L6.3 would be if L6 would be deployed evenly. Similarly L8.1 will be deployed ahead of L5.3 at the plane where L5.3 would be if deployed evenly. This way first 18 planes will be ready earlier than L6.3 and L5.3 arrive to the target orbit. Then I think L9, L10, L11, etc. will be deployed in groups of 3 planes 5 degrees apart in all slots between previously deployed planes. Illustration:

Re: Starlink : General Discussion - Thread 2
« Reply #1335 on: 04/18/2020 10:28 pm »
Starlink base elements (~ 4ft white satellite domes) showed up at Boca Chica today.

Offline DistantTemple

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Re: Starlink : General Discussion - Thread 2
« Reply #1336 on: 04/18/2020 10:41 pm »
After this next launch (6) SpaceX will have a minimum for an operational network with U.S. coverage. 
I think Alaska/Canada, 70 deg., with 3 launches will be next. 
What will after that?

The new modification will take 6-9 months to get approved. I believe L7.1 will target the plane where L6.3 would be if L6 would be deployed evenly. Similarly L8.1 will be deployed ahead of L5.3 at the plane where L5.3 would be if deployed evenly. This way first 18 planes will be ready earlier than L6.3 and L5.3 arrive to the target orbit. Then I think L9, L10, L11, etc. will be deployed in groups of 3 planes 5 degrees apart in all slots between previously deployed planes. Illustration:
Hummy I wish I understood your diagram.... And I bet I'm not the only one who doesn't. I would expect only half a circle, as the other half, is the rest of the same orbits!!! Is ist a cross section at the equator? A q. tutorial would be helpful.

Edit: You know about these things, but since this follows a previous successful amendment that was effectively the same for a different section of its constellation, is there a possibility it may be fast tracked?
« Last Edit: 04/18/2020 10:44 pm by DistantTemple »
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Offline RedLineTrain

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Re: Starlink : General Discussion - Thread 2
« Reply #1337 on: 04/18/2020 10:43 pm »
Noticed that the Organizational Information document shows Musk owning 47.4% of SpaceX, with 78.3% voting control.

Offline Hummy

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Re: Starlink : General Discussion - Thread 2
« Reply #1338 on: 04/19/2020 01:16 am »
After this next launch (6) SpaceX will have a minimum for an operational network with U.S. coverage. 
I think Alaska/Canada, 70 deg., with 3 launches will be next. 
What will after that?

The new modification will take 6-9 months to get approved. I believe L7.1 will target the plane where L6.3 would be if L6 would be deployed evenly. Similarly L8.1 will be deployed ahead of L5.3 at the plane where L5.3 would be if deployed evenly. This way first 18 planes will be ready earlier than L6.3 and L5.3 arrive to the target orbit. Then I think L9, L10, L11, etc. will be deployed in groups of 3 planes 5 degrees apart in all slots between previously deployed planes. Illustration:
Hummy I wish I understood your diagram.... And I bet I'm not the only one who doesn't. I would expect only half a circle, as the other half, is the rest of the same orbits!!! Is ist a cross section at the equator? A q. tutorial would be helpful.

Edit: You know about these things, but since this follows a previous successful amendment that was effectively the same for a different section of its constellation, is there a possibility it may be fast tracked?

The dots in the diagram are ascending nodes where a satellite in a plane crosses the equatorial plane going up from the Southern into the Northern Hemisphere (North is up, South is down by convention). L1.1 satellites go up at 0 degrees and go down at 180 degrees. L4.1 satellites go up at 180 degrees and go down at 0 degrees. The orbits are separated by a few kilometers at 0 and 180 degrees altitude-wise. Below is a screenshot of Celestrak showing direction of L1.1 and L4.1 satellites when they are close to each other above the equator.

I don't think the FCC can fast track this modification. The FCC has to give time to competitors sharing the spectrum (OneWeb, Telesat, SES, Viasat, and other GEO operators) to analyze the modification and submit objections. The previous interference analysis does not apply verbatim. The competitors will drag. Then the FCC needs to analyze the objections.

Re: Starlink : General Discussion - Thread 2
« Reply #1339 on: 04/19/2020 02:17 am »
After this next launch (6) SpaceX will have a minimum for an operational network with U.S. coverage. 
I think Alaska/Canada, 70 deg., with 3 launches will be next. 
What will after that?

The new modification will take 6-9 months to get approved. I believe L7.1 will target the plane where L6.3 would be if L6 would be deployed evenly. Similarly L8.1 will be deployed ahead of L5.3 at the plane where L5.3 would be if deployed evenly. This way first 18 planes will be ready earlier than L6.3 and L5.3 arrive to the target orbit. Then I think L9, L10, L11, etc. will be deployed in groups of 3 planes 5 degrees apart in all slots between previously deployed planes. Illustration:
Hummy I wish I understood your diagram.... And I bet I'm not the only one who doesn't. I would expect only half a circle, as the other half, is the rest of the same orbits!!! Is ist a cross section at the equator? A q. tutorial would be helpful.

Edit: You know about these things, but since this follows a previous successful amendment that was effectively the same for a different section of its constellation, is there a possibility it may be fast tracked?

The dots in the diagram are ascending nodes where a satellite in a plane crosses the equatorial plane going up from the Southern into the Northern Hemisphere (North is up, South is down by convention). L1.1 satellites go up at 0 degrees and go down at 180 degrees. L4.1 satellites go up at 180 degrees and go down at 0 degrees. The orbits are separated by a few kilometers at 0 and 180 degrees altitude-wise. Below is a screenshot of Celestrak showing direction of L1.1 and L4.1 satellites when they are close to each other above the equator.

I don't think the FCC can fast track this modification. The FCC has to give time to competitors sharing the spectrum (OneWeb, Telesat, SES, Viasat, and other GEO operators) to analyze the modification and submit objections. The previous interference analysis does not apply verbatim. The competitors will drag. Then the FCC needs to analyze the objections.

While I fear you are right I hope you are wrong. 
6-9 months is 12-18 launches or 720-1080 satellites is a long time for SpaceX. 
Recently the FCC has surprised me on how quickly it okay'd Starlink changes.   
The altitude changes are simple compared to spectrum.   
Here's hoping... 

Tags: pole flip 
 

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