Author Topic: Starlink : General Discussion - Thread 3  (Read 346169 times)

Offline dplot123

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Re: Starlink : General Discussion - Thread 3
« Reply #600 on: 10/02/2022 11:58 pm »
Mike Puchol updated https://starlink.sx to include a Starlink country capacity simulator. He also has a medium post explaining the intricacies of the capacity simulation and how Starlink works.

https://mikepuchol.com/modeling-starlink-capacity-843b2387f501

Offline Vultur

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Re: Starlink : General Discussion - Thread 3
« Reply #601 on: 10/03/2022 06:36 pm »
"Space lasers" just sounds so awesome/ SF-ish.

Offline Star One

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Re: Starlink : General Discussion - Thread 3
« Reply #602 on: 10/03/2022 06:48 pm »
If there’s a specific thread for this kind of thing I cannot find it.

https://twitter.com/ari_rex/status/1576797509795532800

Quote
Space X satellites as they pass through Milky Way over canola fields near Harden NSW Australia.
Last year this image won the first place in #aippawards (Australian Institute of Professional Photographers)
« Last Edit: 10/03/2022 06:49 pm by Star One »

Offline deadman1204

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Re: Starlink : General Discussion - Thread 3
« Reply #603 on: 10/04/2022 02:03 pm »
I've heard that starlinks are getting brighter again (instead of dimmer).
They no longer have visors, because they might interfere with laser links. As a result, all the newer birds will be brighter.

Offline groknull

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Re: Starlink : General Discussion - Thread 3
« Reply #604 on: 10/04/2022 08:37 pm »
I've heard that starlinks are getting brighter again (instead of dimmer).
They no longer have visors, because they might interfere with laser links. As a result, all the newer birds will be brighter.

Source?

Offline Robotbeat

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Re: Starlink : General Discussion - Thread 3
« Reply #605 on: 10/04/2022 09:35 pm »
Yeah, Starlinks actually use a highly reflective dielectric mirror sort of thing to reflect sunlight away from the Earth instead of absorbing it like with the shield thing.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Asteroza

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Re: Starlink : General Discussion - Thread 3
« Reply #606 on: 10/05/2022 12:30 am »
I've heard that starlinks are getting brighter again (instead of dimmer).
They no longer have visors, because they might interfere with laser links. As a result, all the newer birds will be brighter.

I don't remember visor removal having to do with ISL line of sight blockage, plus the ISL's are located on the edge of the satellite bus with extremely clear line of sight to the left/right/forward/back which are the primary directions of use (not down)

Online DanClemmensen

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Re: Starlink : General Discussion - Thread 3
« Reply #607 on: 10/05/2022 01:05 am »
I've heard that starlinks are getting brighter again (instead of dimmer).
They no longer have visors, because they might interfere with laser links. As a result, all the newer birds will be brighter.

I don't remember visor removal having to do with ISL line of sight blockage, plus the ISL's are located on the edge of the satellite bus with extremely clear line of sight to the left/right/forward/back which are the primary directions of use (not down)
I have not seen a diagram of Starlink's proposed ISL scheme, but the architectures I am familiar with also link planes at differing altitudes. You don't have to point up or down much to hit a higher or lower satellite if it is far enough away, though. Also note that satellites in the same orbit are somewhat below your XY plane because the orbit is curved, and you need some additional deflection because you will be tilted. I'm guessing that +-20 degrees deflection in the Z direction will be more than adequate.

Offline su27k

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Re: Starlink : General Discussion - Thread 3
« Reply #608 on: 10/05/2022 02:47 am »
I've heard that starlinks are getting brighter again (instead of dimmer).
They no longer have visors, because they might interfere with laser links. As a result, all the newer birds will be brighter.

Source?

It was discussed in the Impacts of Large Satellite Constellations on Astronomy thread a few months ago, as far as I can see it's an unpublished result from a Russian observatory, I would wait for published result before reaching any conclusions.

Offline OceanCat

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Re: Starlink : General Discussion - Thread 3
« Reply #609 on: 10/05/2022 05:45 am »
Another Gen2 filing https://licensing.fcc.gov/myibfs/download.do?attachment_key=17429628

Quote
SATELLITE DIMENSIONS
The tables below present information for the current form factors of SpaceX Gen2
satellites: two of which will be launched initially on Falcon 9 rockets and one that will be launched
on Starship. For convenience, these satellites are labeled satellites F9-1, F9-2, and Starship,
respectively. Note that to better reflect a non-maneuverable satellite in a tumbling deorbit a scaling
factor has been applied to the area-to-mass ratios used with NASA’s Debris Assessment Software
(“DAS”). Specifically, a factor of 0.5 has been applied to the two larger satellites and a factor of
0.516 has been applied for the smallest one. Following the tables, SpaceX includes sample logs
from its DAS analyses for each of the current Gen2 form factors.

Quote
Launch cadence to support rapid broadband deployment. SpaceX remains committed to
deploying its Gen2 constellation as quickly as possible to meet the growing needs of consumers
throughout the country for high-speed, low-latency broadband service. In the previous Voluntary
Supplement, SpaceX explained that it plans to launch satellites for its Gen2 constellation beginning
with its three 500-kilometer shells, followed by satellites in the lower-altitude shells.16 Although
its specific launch cadence is being finalized, SpaceX anticipates launching satellites into the Gen2
constellation at a rate of at least once per week during 2023, with a more rapid cadence over time.
While the number of satellites per launch will vary depending on the launch vehicle used and
whether any other payloads are involved, SpaceX expects that launches will have approximately
twenty to sixty satellites on each Falcon 9 launch and approximately fifty to one hundred satellites
initially on each Starship launch, with a variable number of satellites per launch as Starship and
Falcon 9 capabilities develop over time.

There is more in the filing.

Offline su27k

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Re: Starlink : General Discussion - Thread 3
« Reply #610 on: 10/05/2022 06:02 am »
I wonder if F9-1 is just the current v1.5 satellite.

Also interesting that the larger versions have 2 solar arrays

Another interesting thing is that the frequency of the "Emergency beacons for non-U.S. operation" is 137-138 MHz (transmit) and 148-150.05 MHz (receive), this is the same band used by Swarm IoT satellites (137-138 MHz for downlink, 148-149.95 Mhz uplink).
« Last Edit: 10/05/2022 08:40 am by su27k »

Offline kevin-rf

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Re: Starlink : General Discussion - Thread 3
« Reply #611 on: 10/05/2022 11:23 am »
I think F9-1 are the current v1.5's,

It does make me wonder what they will fill shell 2 with.  v1.5's or v2's.

v2 seems to be getting closer. SpaceX is getting close to completing  shells 4 and 3.
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Offline Robotbeat

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Re: Starlink : General Discussion - Thread 3
« Reply #612 on: 10/05/2022 01:36 pm »

257 square meters at 90% full factor and 20% efficiency of 1360W/m^2 solar at 1AU is 63kW peak per satellite. 30,000 of those satellites is 1.9GW. They’ll be in shade, say, 40% of the time, so that’s over 1Gigawatt of average power consumption. About 8 square kilometers of surface are of solar panels.

This is approximately the scale needed for space-based solar power.

If they can build and launch this constellation for less than $10 billion, that basically means you could build a space based solar power station with comparable cost as new nuclear. (…ground segment cost is a question, of course. And you have much of the energy being used for electric thrusters, not transmission.)
« Last Edit: 10/05/2022 01:44 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline freddo411

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Re: Starlink : General Discussion - Thread 3
« Reply #613 on: 10/05/2022 01:39 pm »

257 square meters at 90% full factor and 20% efficiency of 1360W/m^2 solar at 1AU is 63kW peak per satellite. 30,000 of those satellites is 1.9GW. They’ll be in shade, say, 40% of the time, so that’s over 1Gigawatt of average power consumption. About 8 square kilometers of surface are of solar panels.

This is approximately the scale needed for space-based solar power.

Wow.   SpaceX continues to impress with their innovations and the SCALE


Offline deadman1204

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Re: Starlink : General Discussion - Thread 3
« Reply #614 on: 10/05/2022 01:49 pm »
I've heard that starlinks are getting brighter again (instead of dimmer).
They no longer have visors, because they might interfere with laser links. As a result, all the newer birds will be brighter.

Source?
https://skyandtelescope.org/astronomy-news/newest-starlink-satellites-have-gotten-brighter-again/

Offline Robotbeat

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Re: Starlink : General Discussion - Thread 3
« Reply #615 on: 10/05/2022 01:53 pm »
I've heard that starlinks are getting brighter again (instead of dimmer).
They no longer have visors, because they might interfere with laser links. As a result, all the newer birds will be brighter.

Source?
https://skyandtelescope.org/astronomy-news/newest-starlink-satellites-have-gotten-brighter-again/
0.6 magnitude brighter than visorsats, but still dimmer than original Starlinks.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Redclaws

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Re: Starlink : General Discussion - Thread 3
« Reply #616 on: 10/05/2022 01:53 pm »

257 square meters at 90% full factor and 20% efficiency of 1360W/m^2 solar at 1AU is 63kW peak per satellite. 30,000 of those satellites is 1.9GW. They’ll be in shade, say, 40% of the time, so that’s over 1Gigawatt of average power consumption. About 8 square kilometers of surface are of solar panels.

This is approximately the scale needed for space-based solar power.

If they can build and launch this constellation for less than $10 billion, that basically means you could build a space based solar power station with comparable cost as new nuclear. (…ground segment cost is a question, of course. And you have much of the energy being used for electric thrusters, not transmission.)

This ignores loss and capacity issues (when can they see the ground station) entirely, which is going to cut this by a *lot*.  Like, a lot a lot.  I don’t think it makes the equations close.

Offline deadman1204

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Re: Starlink : General Discussion - Thread 3
« Reply #617 on: 10/05/2022 03:34 pm »
I've heard that starlinks are getting brighter again (instead of dimmer).
They no longer have visors, because they might interfere with laser links. As a result, all the newer birds will be brighter.

Source?
https://skyandtelescope.org/astronomy-news/newest-starlink-satellites-have-gotten-brighter-again/
0.6 magnitude brighter than visorsats, but still dimmer than original Starlinks.
So starlinks are getting brighter again. They will also start getting even brighter with the larger sized ones.

This "dimmer than original" covers up the elephant in the room that is always ignored. They are only at the smaller magnitude when they reach final orbit. However, there are always hundreds of satellites on their way up to orbit (which takes several months. Starship is gonna change this to possibly thousands). In a couple years, there will also start to be many hundreds (or thousands) constantly on their way DOWN from orbit to be removed as they hit their 5yr lifespan or whatever and are replaced. So while some starlink satellites are at their minimum magnitude, there will always be a large number of satellites that are much brighter. The constellation will never be finished, there will always be many hundreds on their way up or down.

Offline oldAtlas_Eguy

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Re: Starlink : General Discussion - Thread 3
« Reply #618 on: 10/05/2022 03:40 pm »
FOR THIS THREAD the key discusion of the size of the solar arrays is the relative increase in throughput that the F9-2 and the Starship versions would have over that of a V1.5 sat. The F9-2 will most likely have a 4X throughput increase to a possible 5X increase. The Starship one a possible 8X to 12X throughput increase.

So if V1.5 can support a worldwide total subscribers of up to 4-8M with 4400 sats. The Starship V2 would support worldwide subscribers totals of 32-64M.

Once the Starship ones start launching in volume. SpaceX market cap valuation will ikely jump to significantly greater than even 300B. Terminal build rates of 2M/yr will mean that it would take 16yrs to reach the 32M level. So also expect that once Starship launches start in earnest also expect significant build rate increases for terminals doubling or more the build rates.

Offline RedLineTrain

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Re: Starlink : General Discussion - Thread 3
« Reply #619 on: 10/05/2022 03:45 pm »
I've heard that starlinks are getting brighter again (instead of dimmer).
They no longer have visors, because they might interfere with laser links. As a result, all the newer birds will be brighter.

Source?
https://skyandtelescope.org/astronomy-news/newest-starlink-satellites-have-gotten-brighter-again/
0.6 magnitude brighter than visorsats, but still dimmer than original Starlinks.
So starlinks are getting brighter again. They will also start getting even brighter with the larger sized ones.

This "dimmer than original" covers up the elephant in the room that is always ignored. They are only at the smaller magnitude when they reach final orbit. However, there are always hundreds of satellites on their way up to orbit (which takes several months. Starship is gonna change this to possibly thousands). In a couple years, there will also start to be many hundreds (or thousands) constantly on their way DOWN from orbit to be removed as they hit their 5yr lifespan or whatever and are replaced. So while some starlink satellites are at their minimum magnitude, there will always be a large number of satellites that are much brighter. The constellation will never be finished, there will always be many hundreds on their way up or down.

Gen2 will be using an improved dielectric mirror film.  It appears that v1.5 satellites on the Gen1 constellation have so far used the old dielectric mirror film.

https://api.starlink.com/public-files/BrightnessMitigationBestPracticesSatelliteOperators.pdf

It's a work in progress.

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