Author Topic: Starlink : General Discussion - Thread 3  (Read 343416 times)

Offline su27k

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Offline vaporcobra

Re: Starlink : General Discussion - Thread 3
« Reply #861 on: 02/01/2023 05:47 am »
Dumb question, not sure if it's been answered before (I tend not to follow SpaceX threads too closely): for the Starlink 2 satellites to be launched on Starship, are they planning any near-polar inclination satellites to go with their mostly mid-inclination satellites? If so, can Starship hit polar orbits from the Cape, or will they need to do a Starship launch facility in Vandenberg? Is that something that's in the works? Someone was just asking me about Starship being able to deliver payloads to SSO, and I wasn't sure if they were actively planning to do a facility that could enable SSO/polar launches.

~Jon

It's a fair question. To some extent, Starship is (theoretically) so capable that "offensively inefficient doglegs" may be an accurate answer.

Then there's the harder option of demonstrating enough reliability for Starship to follow in Falcon's footsteps and be certified to overfly Cuba. Once that's possible, Starship will also probably be allowed to overfly Mexico for polar trajectories out of Boca Chica.

Then there's refueling: probably just as far away as the land-overflight-through-reliability solution, but still potentially viable once refueling is routine.

Finally, the most annoying, expensive, and obvious option: build one or several new pads in more convenient areas. Would require new FAA EAs or at least EIS' in all cases, but SpaceX could potentially convert SLC-4, SLC-6 if ULA gives it up, or another unused VSFB site. At CCSFS, I believe there are a few abandoned southerly pads that could be converted and would be more favorable for polar trajectories than KSC LC-39A and LC-49. And while it's clear SpaceX isn't very enthusiastic about them, there are also floating platforms like Deimos/Phobos.

If the full Starlink Gen2 constellation SpaceX proposed is eventually approved, they'll need to launch 3600 satellites to 96.9 degrees and a total of ~500 satellites to 115.7 and 148 degrees, so they clearly think they have a solution. My guess is the plan is to keep flying Falcon for another 10+ years, gain enough experience with Starship for it to be viewed as equally reliable, and then go with the Cuba/Mexico overflight option from pads at Boca and the Cape - with expensive offshore platforms or a VSFB pad as a backup option.

Offline kevin-rf

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Re: Starlink : General Discussion - Thread 3
« Reply #862 on: 02/01/2023 11:12 am »
Do you really need 3600 to 97.6 degrees? The actual population density (research bases and transcon aircraft) is quite low. They only planned 520 satellies to 97.6 for Phase 1.

3600 to the 70 degrees, with larger populations in Alaska, Canada, Finland,  Norway, Sweden makes more sense.

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Offline DanClemmensen

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Re: Starlink : General Discussion - Thread 3
« Reply #863 on: 02/01/2023 02:11 pm »
Do you really need 3600 to 97.6 degrees? The actual population density (research bases and transcon aircraft) is quite low. They only planned 520 satellies to 97.6 for Phase 1.

3600 to the 70 degrees, with larger populations in Alaska, Canada, Finland,  Norway, Sweden makes more sense.
It's not about density. It's about continuous coverage. Fortunately, you need fewer satellites in these near-polar orbits to provide this, because the orbits converge near the poles. That's why "only" 520 satellites suffice. However, the planes diverge as the satellites get further from the poles, so if you are counting on these satellites to provide continuous coverage above the highest latitude covered by the "normal" orbits, then you must compute for that latitude.

Offline RedLineTrain

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Re: Starlink : General Discussion - Thread 3
« Reply #864 on: 02/01/2023 02:36 pm »
Do you really need 3600 to 97.6 degrees? The actual population density (research bases and transcon aircraft) is quite low. They only planned 520 satellies to 97.6 for Phase 1.

3600 to the 70 degrees, with larger populations in Alaska, Canada, Finland,  Norway, Sweden makes more sense.

My guess is that polar transcontinental data transport is also considered important from a 1/10th-of-the-whole standpoint.

Also, if Starlink supports Starshield as part of the communications layer, polar peak capacity at the poles might be important.
« Last Edit: 02/01/2023 02:41 pm by RedLineTrain »

Offline kevin-rf

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Re: Starlink : General Discussion - Thread 3
« Reply #865 on: 02/01/2023 03:31 pm »
Fun with math,

The current Shell 2 spacing of 58 satellites per plane works out to roughly 690km between satellites.
Spacing between polar planes at 70 degrees (when you include the 6 Shell 2, and 4 Phase 1 Shell 5 planes) is 687 km, and much less at the poles.

Interesting that they are roughly the same.

More fun, Shell's 1 and 4 have a satellite spacing of roughly 1800km in each plane and  550 km between planes. Which was sufficient to launched service with Shell 1. That said, Planes 1 and 4 are designed to complement one another, so both those numbers when combined are half.

Getting back to the polar plane, the user density is a small number research stations and maybe weather stations above 70 degrees and the few hundred transcon  flights transiting the pole at any given point in time? While transcon is lucrative, and most likely high bandwidth, 3600 might be a bit overkill. SpaceX at the moment seems happy with only 2/3 of the Shell 3 launched. Assuming the 360km shells ever gets built. The biggest demand are the waitlisted areas below 43 degrees... Odd, SpaceX is maximizing it's phase 2 launches to 43 degrees. Best bang for the buck currently is orbits maximized to spend time below 43 degrees.
 
« Last Edit: 02/01/2023 03:32 pm by kevin-rf »
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Offline JayWee

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Re: Starlink : General Discussion - Thread 3
« Reply #866 on: 02/02/2023 12:29 am »
Getting back to the polar plane, the user density is a small number research stations and maybe weather stations above 70 degrees and the few hundred transcon  flights transiting the pole at any given point in time?

While transcon is lucrative, and most likely high bandwidth, 3600 might be a bit overkill.
2 thoughts:
- 3600 sounds like a lot, but it's 10% of the constellation.
- How much of the North-South ISL bandwidth these polar planes are able to carry? (Say, if I wanted Europe-Australia purely via Starlink)

Offline kevin-rf

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Re: Starlink : General Discussion - Thread 3
« Reply #867 on: 02/02/2023 03:02 am »
Uuuum, a quick look shows the most direct (least hops) starlink to starlink from Austrailia to Europe is the descending 53 degree plane.

While valid, the satellites are launched for both in plane,  and cross plane ISL. So you might be hard pressed to find optimal ISL traffic that goes over the poles. Maybe Asia to North America?

When SpaceX completes Shell 2. It should increase the number of satellites in the sky above the wait listed continental US by roughly 20% (ignoring phase 2).
« Last Edit: 02/02/2023 03:03 am by kevin-rf »
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Offline kevin-rf

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Re: Starlink : General Discussion - Thread 3
« Reply #868 on: 02/02/2023 03:18 am »
On ISL, the availability of Starlink in Brazil makes me wonder if SpaceX currently has operational plane to plane ISL. With only the in plane ISL currently in use.

The coming soon area on Brazil's East coast matches up well with the 53 degree descending node. All ground stations in Brazil are West and South of Salvador. They are clearly using ISL to provide coverage in the Amazon, but not the East area?
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Offline su27k

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Re: Starlink : General Discussion - Thread 3
« Reply #869 on: 02/07/2023 03:00 am »
https://twitter.com/VirtuallyNathan/status/1620403108957552640

Quote from: Nathan Owens
Starlink’s Fair Use Policy is now pushed back to NET April 2023

Quote from: Starlink Insider
Interesting. It seems, at least judging by user reviews on FB & Reddit, that they got some of their speed issues in North America under control. May simply not be as urgent as it was before?

Quote from: Nathan Owens
Could be! Perhaps just technically challenging to implement as well
« Last Edit: 02/07/2023 03:01 am by su27k »

Online FutureSpaceTourist

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Re: Starlink : General Discussion - Thread 3
« Reply #870 on: 02/09/2023 12:01 am »
Big news:

https://twitter.com/thesheetztweetz/status/1623426945634430978

Quote
SpaceX president & COO Gwynne Shotwell, at #CST2023:

"This year Starlink will make money. We actually had a cash flow positive quarter last year."

Offline su27k

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Re: Starlink : General Discussion - Thread 3
« Reply #871 on: 02/09/2023 03:41 am »
More accurate Shotwell quote: https://spacenews.com/shotwell-ukraine-weaponized-starlink-in-war-against-russia/

Quote
While Musk said in October that Starlink was losing money, Shotwell offered a more upbeat assessment. “This year Starlink will make money,” she said, noting that the company’s Falcon launch vehicle and Dragon spacecraft, and other unspecified work, already makes money.

“We actually had a cashflow positive quarter last year, excluding launch. This year, they’re paying for their own launches, and they will still make money,” she said.

Offline Asteroza

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Re: Starlink : General Discussion - Thread 3
« Reply #872 on: 02/09/2023 07:02 am »
More accurate Shotwell quote: https://spacenews.com/shotwell-ukraine-weaponized-starlink-in-war-against-russia/

Quote
While Musk said in October that Starlink was losing money, Shotwell offered a more upbeat assessment. “This year Starlink will make money,” she said, noting that the company’s Falcon launch vehicle and Dragon spacecraft, and other unspecified work, already makes money.

“We actually had a cashflow positive quarter last year, excluding launch. This year, they’re paying for their own launches, and they will still make money,” she said.

That's it folks. 2023 is officially the year of the megaconstellation. Hat's off to SpaceX for proving it.

Offline geza

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Re: Starlink : General Discussion - Thread 3
« Reply #873 on: 02/14/2023 05:25 am »
Do we know, how many Starship launches are needed, and how fast, to deploy the Starlink constellation and satisfy FCC requirement? I asking this, because of the news about selling Phobos & Deimos. Shotwell said also that 100-200 launches are needed before human flight. Probably, they are Starlink flights.

Offline vaporcobra

Re: Starlink : General Discussion - Thread 3
« Reply #874 on: 02/14/2023 05:59 am »
Do we know, how many Starship launches are needed, and how fast, to deploy the Starlink constellation and satisfy FCC requirement? I asking this, because of the news about selling Phobos & Deimos. Shotwell said also that 100-200 launches are needed before human flight. Probably, they are Starlink flights.

While the FCC's arbitrary partial grant is ridiculous, it makes that problem a lot easier for SpaceX in the interim. For 7500 full-size V2 satellites and assuming ~60 sats per launch, SpaceX only needs about 12 Starship launches per year between H2 2022 and Dec 2028 to hit the 50% milestone. The 50-100% milestone would then require 24/year.

Assuming the FCC actually does grant permission for more Gen2 satellites, you can then simply 4X the above figures to get a worst-case idea of the cadence required. In practice, the staggered grants would take the edge off and require fewer Starship launches per year to hit deployment milestones than if the whole constellation had been approved at once.

Edit: Should add that the situation will become even more favorable if SpaceX quickly develops a proper payload bay (or stretched fairing) and can use most of Starship's performance. Perhaps 80-125 V2.0 satellites per launch if/when that happens.
« Last Edit: 02/14/2023 06:05 am by vaporcobra »

Offline Asteroza

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Re: Starlink : General Discussion - Thread 3
« Reply #875 on: 02/14/2023 06:22 am »
Do we know, how many Starship launches are needed, and how fast, to deploy the Starlink constellation and satisfy FCC requirement? I asking this, because of the news about selling Phobos & Deimos. Shotwell said also that 100-200 launches are needed before human flight. Probably, they are Starlink flights.

While the FCC's arbitrary partial grant is ridiculous, it makes that problem a lot easier for SpaceX in the interim. For 7500 full-size V2 satellites and assuming ~60 sats per launch, SpaceX only needs about 12 Starship launches per year between H2 2022 and Dec 2028 to hit the 50% milestone. The 50-100% milestone would then require 24/year.

Assuming the FCC actually does grant permission for more Gen2 satellites, you can then simply 4X the above figures to get a worst-case idea of the cadence required. In practice, the staggered grants would take the edge off and require fewer Starship launches per year to hit deployment milestones than if the whole constellation had been approved at once.

Edit: Should add that the situation will become even more favorable if SpaceX quickly develops a proper payload bay (or stretched fairing) and can use most of Starship's performance. Perhaps 80-125 V2.0 satellites per launch if/when that happens.

Minimum 12 launches a year, more like 24, implies both Florida launch is active and Texas is at max 6 launches a year...

Offline DanClemmensen

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Re: Starlink : General Discussion - Thread 3
« Reply #876 on: 02/14/2023 01:49 pm »
Do we know, how many Starship launches are needed, and how fast, to deploy the Starlink constellation and satisfy FCC requirement? I asking this, because of the news about selling Phobos & Deimos. Shotwell said also that 100-200 launches are needed before human flight. Probably, they are Starlink flights.

While the FCC's arbitrary partial grant is ridiculous, it makes that problem a lot easier for SpaceX in the interim. For 7500 full-size V2 satellites and assuming ~60 sats per launch, SpaceX only needs about 12 Starship launches per year between H2 2022 and Dec 2028 to hit the 50% milestone. The 50-100% milestone would then require 24/year.

Assuming the FCC actually does grant permission for more Gen2 satellites, you can then simply 4X the above figures to get a worst-case idea of the cadence required. In practice, the staggered grants would take the edge off and require fewer Starship launches per year to hit deployment milestones than if the whole constellation had been approved at once.

Edit: Should add that the situation will become even more favorable if SpaceX quickly develops a proper payload bay (or stretched fairing) and can use most of Starship's performance. Perhaps 80-125 V2.0 satellites per launch if/when that happens.
The old Pez animation showed 54 satellites per launch. 7500/54= 139 launches.
The mass of the Starship version of the V2 satellite been stated to be about 1370 kg. For a 150 tonne mass constrained stretched Starship, this is 109 satellites per launch, except the stretch modification and its dispenser are not zero mass, so randomly guess 100 satellites per launch. 7500/100=75 launches. If SpaceX can begin normal operations in January 2024, they will have 5 years (60 months)  to hit 50%: 70 launches (conservative) 38 launches (aggressive). But they also have about 20 Starship launches for HLS to complete in that timeframe, so  between 60 and 90 launches in 60 months.

Note: stretched non-EDL Starship is easy. Stretched EDL starship is not so easy.

Offline oldAtlas_Eguy

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Re: Starlink : General Discussion - Thread 3
« Reply #877 on: 02/14/2023 06:54 pm »
A value of 60 to 90 launches in 5 year period is 12 or 18 launches a year average.

I do not see that Starship will be a steady state launch rate. Starting at less than 12 and then ending significantly well above 36 per year at the 5 year point (2028). Hence by 2028 total launches should reach above 100 easily. Unless there are a lot of "engineering issues" encountered that requiers multiple years to solve before the launch rate growth occurs.

Offline DanClemmensen

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Re: Starlink : General Discussion - Thread 3
« Reply #878 on: 02/14/2023 07:45 pm »
A value of 60 to 90 launches in 5 year period is 12 or 18 launches a year average.

I do not see that Starship will be a steady state launch rate. Starting at less than 12 and then ending significantly well above 36 per year at the 5 year point (2028). Hence by 2028 total launches should reach above 100 easily. Unless there are a lot of "engineering issues" encountered that requiers multiple years to solve before the launch rate growth occurs.
Bad news: no modern LV has launched more than a total of 10 times in its first 4 years (2.5/yr).
Good news: Starship is designed for rapid full reuse, so maybe they can do 10 launches in the first four year and 100  launches in year 5.

I would love to see a faster ramp. I am an optimist. Maybe SpaceX can ramp more quickly: doubling eash year. Say 5, 10, 20, 40, 80 in years 2024-2028.

Offline Robotbeat

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Re: Starlink : General Discussion - Thread 3
« Reply #879 on: 02/14/2023 07:48 pm »
Also if you want to massage that statistic a bit, Starship has done suborbital tests for years, now.
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