Author Topic: Starlink : General Discussion - Thread 2  (Read 1078327 times)

Offline RedLineTrain

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Re: Starlink : General Discussion - Thread 2
« Reply #1340 on: 04/19/2020 03:07 am »
6 to 9 months likely won't impact the Starlink deployment.  So there's no problem with that pace.

Offline Hummy

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Re: Starlink : General Discussion - Thread 2
« Reply #1341 on: 04/19/2020 03:20 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...

19 more launches are needed to complete 550 km shell to provide coverage of the areas where 99% of the world population lives. I think they'd rather prioritize covering 99% before covering 1% (Alaska, etc.)

Re: Starlink : General Discussion - Thread 2
« Reply #1342 on: 04/19/2020 03:59 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...

19 more launches are needed to complete 550 km shell to provide coverage of the areas where 99% of the world population lives. I think they'd rather prioritize covering 99% before covering 1% (Alaska, etc.)

They don't want to complete the shell yet, just the minimal amount for operational coverage.
Completing the shell adds redundancy and bandwidth which they can add later.

Correcting my prior post...
After this next launch (6) SpaceX will have a minimum for an operational network with northern US coverage 6 more for southern US then 3 for Alaska/Canada. 

Offline gongora

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Re: Starlink : General Discussion - Thread 2
« Reply #1343 on: 04/19/2020 04:18 am »
They don't want to complete the shell yet, just the minimal amount for operational coverage.
Completing the shell adds redundancy and bandwidth which they can add later.

Correcting my prior post...
After this next launch (6) SpaceX will have a minimum for an operational network with northern US coverage 6 more for southern US then 3 for Alaska/Canada.

They do want to complete the initial shell, and where the heck are you getting 3 more launches for Alaska/Canada?  It seems you're just making up numbers.
« Last Edit: 04/19/2020 04:20 am by gongora »

Offline groknull

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Re: Starlink : General Discussion - Thread 2
« Reply #1344 on: 04/19/2020 05:29 am »
The recent SpaceX FCC filing discussed in the "Starlink : New FCC Filings" thread includes significant proposed changes to the constellation.

Post with the link to the filing on the FCC website (TorenAltair):
https://forum.nasaspaceflight.com/index.php?topic=46726.msg2069971#msg2069971
Extraction of the proposed orbital plane changes (gongora):
https://forum.nasaspaceflight.com/index.php?topic=46726.msg2069983#msg2069983
Excerpt of the orbital plane spreadsheet and source spreadsheet (gongora):
https://forum.nasaspaceflight.com/index.php?topic=46726.msg2070008#msg2070008
(The spreadsheet is apparently in the .jet file in the filing which some devices and systems may not be able to read.)

Since I was having a little trouble visualizing the proposed orbital planes, I did a quick and dirty CAD model using the data in the spreadsheet.  These models show the proposed orbits, but not the individual satellites.  These models do not show the configurations from previous filings.

Color codes:
Red: 540km, 53deg inclination, 5deg RAAN increment, 0deg RAAN offset, 72 planes, 22 satellites per plane
Yellow: 550km, 53.2deg inclination, 5deg RAAN increment, 2.5deg RAAN offset, 72 planes, 22 satellites per plane
Green: 570km, 70deg inclination, 10deg RAAN increment, 0deg RAAN offset, 36 planes, 20 satellites per plane
Magenta: 560km, 97.6deg inclination, 60deg RAAN increment, 3.7deg RAAN offset, 6 planes, 58 satellites per plane
Cyan: 560km, 97.6deg inclination, 12deg RAAN increment, 75.7deg RAAN offset, 4 planes, 43 satellites per plane

Image descriptions:
1: All 4 altitudes; 540km, 550km, 560km, 570km (all rows in the spreadsheet)
2: 540km, 550km only
3: 570km, 560km (both 58 and 43 satellite subsets)
4: 560km only (both 58 and 43 satellite subsets)
5: 560km only, 6 planes of 58 satellites
6: 560km only, 4 planes of 43 satellites

Edit: added inclinations to color code index (540km and 550km do have slightly different inclinations)
Edit 2: I got a sign wrong on the model, so the point of view for these images is about 210deg azimuth, 60deg elevation
« Last Edit: 04/19/2020 06:53 pm by groknull »

Offline Ronsmytheiii

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Re: Starlink : General Discussion - Thread 2
« Reply #1345 on: 04/19/2020 09:47 am »

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.


Nope, its very public. The Space Development Agency recently issued a RFP to develop a mesh-link satellite constellation using laser inter links:

Quote
Following Tranche 0, the SDA plans to continuously upgrade and add to its on orbit constellation in two year cycles, with Tranche 1 coming online in FY2024, Tranche 2 supplementing the system in FY2026. The SDA will procure two types of satellites for Tranche 0, with one main difference being that one set of satellites will have enough optical intersatellite links to communicate with other satellites operating in LEO and satellites in medium earth orbit or geosynchronous orbit, while the other will only have enough to communicate with other satellites in LEO.

https://www.c4isrnet.com/battlefield-tech/space/2020/04/06/the-pentagon-will-solicit-its-first-mesh-network-in-space-may-1/
« Last Edit: 04/19/2020 10:09 am by Ronsmytheiii »

Re: Starlink : General Discussion - Thread 2
« Reply #1346 on: 04/19/2020 02:48 pm »
They don't want to complete the shell yet, just the minimal amount for operational coverage.
Completing the shell adds redundancy and bandwidth which they can add later.

Correcting my prior post...
After this next launch (6) SpaceX will have a minimum for an operational network with northern US coverage 6 more for southern US then 3 for Alaska/Canada.

They do want to complete the initial shell, and where the heck are you getting 3 more launches for Alaska/Canada?  It seems you're just making up numbers.

Sorry ... Out of date Musk tweets...  the world moves quickly in Musk time.
I will shut up for now...
« Last Edit: 04/19/2020 03:11 pm by ThomasGadd »

Online M.E.T.

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Re: Starlink : General Discussion - Thread 2
« Reply #1347 on: 04/19/2020 03:09 pm »
Noticed that the Organizational Information document shows Musk owning 47.4% of SpaceX, with 78.3% voting control.

Ah damn. So the recent capital raises dropped him below 50%. I don't understand why he didn't just borrow against his sky high Tesla shares to maintain his 51% stake in SpaceX. Ah well, he knows what he is doing, no doubt.

Offline launchwatcher

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Re: Starlink : General Discussion - Thread 2
« Reply #1348 on: 04/19/2020 03:34 pm »
the architecture for supporting 911 on VoIP in general is confusing to me.
Identifying the location of a VoIP calling line for E911 service is more simple than it appears.

The VoIP providers I've used have asked for an address to associate with each calling line.   Once they have that information it's a  simple database lookup on their end to identify the physical location of the caller and it uses that to identify where to route the call and what metadata to tack on as your physical location.

Of course, if you pick up your VoIP phone or ATA and plug it in while in another city and dial 911 without telling the provider of your new location you'll get the wrong dispatcher.

You'd need something like this with Starlink in any event -- gps coordinates of a starlink antenna on top of an apartment building would not tell you which apartment the subscriber lived in...

Offline docmordrid

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Re: Starlink : General Discussion - Thread 2
« Reply #1349 on: 04/19/2020 03:49 pm »
Noticed that the Organizational Information document shows Musk owning 47.4% of SpaceX, with 78.3% voting control.

Ah damn. So the recent capital raises dropped him below 50%. I don't understand why he didn't just borrow against his sky high Tesla shares to maintain his 51% stake in SpaceX. Ah well, he knows what he is doing, no doubt.

The important part is his 78.3% control of voting shares.

Offline Nomadd

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Re: Starlink : General Discussion - Thread 2
« Reply #1350 on: 04/19/2020 07:04 pm »
 Are those gateway antennas? Behind a wall they just put up near the Boca Chica tracking dishes.
 That would be a good place for them. They're within 100 meters of me, so I could just run an Ethernet cable.
 
« Last Edit: 04/19/2020 07:22 pm by Nomadd »
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline gongora

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Re: Starlink : General Discussion - Thread 2
« Reply #1351 on: 04/19/2020 07:12 pm »
Do they look like 1.5m dishes?

Offline Nomadd

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Re: Starlink : General Discussion - Thread 2
« Reply #1352 on: 04/19/2020 07:14 pm »
Do they look like 1.5m dishes?
The divisions on that wall are probably one foot. Domes are usually about a foot bigger than the dish. Sometimes two feet bigger. They have more dish sizes than dome sizes, so the domes can be a little oversize sometimes.
 One of our vendors tried squeezing too small a dome around a dish once, and air currents were messing things up. The dishes are extremely well balanced and the drive motors are usually smaller than you'd believe. Might be different for these as often as they'd need to move quickly to different targets.

 How many antennas would you expect?
« Last Edit: 04/19/2020 07:22 pm by Nomadd »
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline gongora

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Re: Starlink : General Discussion - Thread 2
« Reply #1353 on: 04/19/2020 07:18 pm »
Their normal Ka gateways are 8 antennas (according to the FCC filings).

Offline gongora

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Re: Starlink : General Discussion - Thread 2
« Reply #1354 on: 04/19/2020 07:21 pm »
This is where the permit says they should be

Offline Nomadd

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Re: Starlink : General Discussion - Thread 2
« Reply #1355 on: 04/19/2020 07:26 pm »
This is where the permit says they should be
That's about 30 feet from where they're sitting.
« Last Edit: 04/19/2020 07:27 pm by Nomadd »
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline OTV Booster

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Re: Starlink : General Discussion - Thread 2
« Reply #1356 on: 04/20/2020 02:49 pm »
Are those gateway antennas? Behind a wall they just put up near the Boca Chica tracking dishes.
 That would be a good place for them. They're within 100 meters of me, so I could just run an Ethernet cable.


Dude, if you got the right gear you could grab a side lobe. Is there an iPhone app for that? ;D
We are on the cusp of revolutionary access to space. One hallmark of a revolution is that there is a disjuncture through which projections do not work. The thread must be picked up anew and the tapestry of history woven with a fresh pattern.

Offline Nomadd

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Re: Starlink : General Discussion - Thread 2
« Reply #1357 on: 04/20/2020 03:17 pm »
Are those gateway antennas? Behind a wall they just put up near the Boca Chica tracking dishes.
 That would be a good place for them. They're within 100 meters of me, so I could just run an Ethernet cable.


Dude, if you got the right gear you could grab a side lobe. Is there an iPhone app for that? ;D
Samsung is still working on their ka band model. Apple and I don't get along.
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline ValmirGP

Re: Starlink : General Discussion - Thread 2
« Reply #1358 on: 04/20/2020 04:36 pm »
What is really funny is that there is a camera pointed straight into Nomadd’s camera. 
Watch out man, they have you on their sights.

Offline Tommyboy

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Re: Starlink : General Discussion - Thread 2
« Reply #1359 on: 04/20/2020 05:43 pm »
What is really funny is that there is a camera pointed straight into Nomadd’s camera. 
Watch out man, they have you on their sights.
They even tried to EMP Nomadd's cam with one of the tracking dishes. They lost.

Tags: pole flip 
 

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