Author Topic: Starlink : General Discussion - Thread 2  (Read 1117794 times)

Offline thirtyone

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Re: Starlink : General Discussion - Thread 2
« Reply #1740 on: 08/10/2020 06:58 pm »
https://twitter.com/cosmos4u/status/1292661826866610177

Quote
Only one data point but from a very experienced observer: the 1st #Starlink of the VisorSat type (as https://t.co/seZL1j7zdT explains) is on station now - and dimmer by several magnitudes: http://www.satobs.org/seesat/Aug-2020/0044.html. Should mean that all future Starlinks become invisible to the eye.

Let's hope some more measurements come out soon - promising, but still a very preliminary observation. Another experienced observer (in that satobs thread) posted another observation set on the same day saying he could see it, but I'm not experienced enough to interpret the data beyond knowing it was visible by a telescope setup:
http://www.satobs.org/seesat/Aug-2020/0066.html
http://www.satobs.org/seesat/Aug-2020/0065.html

Offline meberbs

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Re: Starlink : General Discussion - Thread 2
« Reply #1741 on: 08/10/2020 07:45 pm »
A star of 6.7 magnitude was also visible in the observation. Putting the satellite right at the edge of human eyesight.
It said the satellite was not seen even with binoculars when the 6.7 magnitude star was seen. From this information, you can only say what the satellite was dimmer than, not what it's actual brightness was. Being dimmer than 7 magnitude is not the "edge" of human eyesight from anything I have heard, it is solidly below human eyesight.

Thirtyone posted a link mentioning other observations, but I don't know how to parse meaningful info from that set of data.

Offline thirtyone

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Re: Starlink : General Discussion - Thread 2
« Reply #1742 on: 08/10/2020 11:24 pm »
A star of 6.7 magnitude was also visible in the observation. Putting the satellite right at the edge of human eyesight.
It said the satellite was not seen even with binoculars when the 6.7 magnitude star was seen. From this information, you can only say what the satellite was dimmer than, not what it's actual brightness was. Being dimmer than 7 magnitude is not the "edge" of human eyesight from anything I have heard, it is solidly below human eyesight.

Thirtyone posted a link mentioning other observations, but I don't know how to parse meaningful info from that set of data.

I'm no expert in this area, but I went through the satobs guide to their standard measurement set. http://www.satobs.org/position/IODformat.html. There simply isn't magnitude data in these sets - I think it's a measure of whether or not someone with a good telescope could spot all of these objects, and where in the sky they could be spotted. The only visual data available was that visorsat was visible. You could, potentially, guess what the visibility threshold for that particular observer's setup may have been based on other spotted or not spotted objects, especially given that it seems that night was particularly clear on one dataset (intermittent cloud cover I'd imagine could give misleading measurements).

Offline RedLineTrain

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Re: Starlink : General Discussion - Thread 2
« Reply #1743 on: 08/19/2020 04:28 pm »
Visorsat observed at magnitude 7.0.

Crossposted from the megaconstellation impacts thread...

https://twitter.com/richard_e_cole/status/1295604802966171649

Online aero

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Re: Starlink : General Discussion - Thread 2
« Reply #1744 on: 08/21/2020 02:53 pm »
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Company officials said service will be offered in northern portions of the United States and Canada after 12 satellite fleet deployments, which would increase the size of the constellation to almost 800 satellites

https://www.tesmanian.com/blogs/tesmanian-blog/starlink-sats
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Offline Nomadd

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Re: Starlink : General Discussion - Thread 2
« Reply #1745 on: 08/21/2020 03:43 pm »
Quote
Company officials said service will be offered in northern portions of the United States and Canada after 12 satellite fleet deployments, which would increase the size of the constellation to almost 800 satellites

https://www.tesmanian.com/blogs/tesmanian-blog/starlink-sats
How does 648 plus one more deployment equal "almost 800"? Not that she should have counted the V.9s anyhow.
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Re: Starlink : General Discussion - Thread 2
« Reply #1746 on: 08/21/2020 04:27 pm »
Quote
Company officials said service will be offered in northern portions of the United States and Canada after 12 satellite fleet deployments, which would increase the size of the constellation to almost 800 satellites

https://www.tesmanian.com/blogs/tesmanian-blog/starlink-sats
How does 648 plus one more deployment equal "almost 800"? Not that she should have counted the V.9s anyhow.

Well, it's more than 700!
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Online oldAtlas_Eguy

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Re: Starlink : General Discussion - Thread 2
« Reply #1747 on: 08/21/2020 04:32 pm »
Quote
Company officials said service will be offered in northern portions of the United States and Canada after 12 satellite fleet deployments, which would increase the size of the constellation to almost 800 satellites

https://www.tesmanian.com/blogs/tesmanian-blog/starlink-sats
How does 648 plus one more deployment equal "almost 800"? Not that she should have counted the V.9s anyhow.

Well, it's more than 700!
Ugh, L10 is the 10th V1.0 launch meaning just less than <600 operational V1.0 sats on orbit. Plus <60 V0.9 sats on orbit.

This next launch L11 will bring the total to 700+.

Offline wannamoonbase

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Re: Starlink : General Discussion - Thread 2
« Reply #1748 on: 08/21/2020 04:37 pm »
Are the v0.9's even operational?  I recall reading that they didn't have couldn't provide the service or throughput of the v1.0's and that they wouldn't really be part of the constellation.

Are they just flying the v0.9's to test and characterize the hardware?
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Offline DistantTemple

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Re: Starlink : General Discussion - Thread 2
« Reply #1749 on: 08/21/2020 04:39 pm »
Quote
Company officials said service will be offered in northern portions of the United States and Canada after 12 satellite fleet deployments, which would increase the size of the constellation to almost 800 satellites

https://www.tesmanian.com/blogs/tesmanian-blog/starlink-sats
How does 648 plus one more deployment equal "almost 800"? Not that she should have counted the V.9s anyhow.
Well its only one further launch from about 768, which rounds to 800! and that extra 60 would only be a couple of weeks more, so its "almost" in 2 ways, in fact with yet another additional launch it would be about 828, so thats a 3rd reason to be almost there (since 828 rounds to 800) and since that again is likely another two(ish) weeks, that means that is almost achieved.
Conclusion it is almost 800 in 4 ways, so why beat about the bush?
« Last Edit: 08/21/2020 04:41 pm by DistantTemple »
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Re: Starlink : General Discussion - Thread 2
« Reply #1750 on: 08/21/2020 04:40 pm »
Are the v0.9's even operational?  I recall reading that they didn't have couldn't provide the service or throughput of the v1.0's and that they wouldn't really be part of the constellation.

Are they just flying the v0.9's to test and characterize the hardware?

v0.9 are test sats, not part of the constellation.  They don't have the Ka-band payload to communicate with the gateways.

Offline Frogstar_Robot

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Re: Starlink : General Discussion - Thread 2
« Reply #1751 on: 08/21/2020 04:51 pm »
Having worked in a bistro for a while, I think I see where the math went wrong. 24 x 60 = "about 1500" (from Ars web article). So 12 launches is "about 1500"/2, which equals "about 750", or "almost 800".

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Online matthewkantar

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Re: Starlink : General Discussion - Thread 2
« Reply #1752 on: 08/21/2020 07:28 pm »
Let's not quibble over a couple of hundred satellites, will be a rounding error in no time.

Online oldAtlas_Eguy

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Re: Starlink : General Discussion - Thread 2
« Reply #1753 on: 08/21/2020 09:05 pm »
Are the v0.9's even operational?  I recall reading that they didn't have couldn't provide the service or throughput of the v1.0's and that they wouldn't really be part of the constellation.

Are they just flying the v0.9's to test and characterize the hardware?

v0.9 are test sats, not part of the constellation.  They don't have the Ka-band payload to communicate with the gateways.
Last time we had observation of Gateway sites they had Ku UTs so there is always a capability to use the V0.9 sats if necessary. It is just that in three+ more launches it will not be necessary ever again. 2 to get to the 768 value and then 1 more to replace the V0.9 sats to be at the >750 value for V1.0 sats. Then one more and everything we are quibbling over now will be mute. Timeline for 4 more launches is possibly before end of October or possibly even early October. <60 days from now.

Online aero

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Re: Starlink : General Discussion - Thread 2
« Reply #1754 on: 08/21/2020 09:22 pm »
All this discussion about how many is 800 is interesting, but I thought the more interesting part was:

Quote
Company officials said service will be offered in northern portions of the United States and Canada after 12 satellite fleet deployments,

Now that should give us something more interesting to quibble about! How many are 12?
« Last Edit: 08/21/2020 09:23 pm by aero »
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Offline meberbs

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Re: Starlink : General Discussion - Thread 2
« Reply #1755 on: 08/21/2020 11:45 pm »
All this discussion about how many is 800 is interesting, but I thought the more interesting part was:

Quote
Company officials said service will be offered in northern portions of the United States and Canada after 12 satellite fleet deployments,

Now that should give us something more interesting to quibble about! How many are 12?
That seems easy* to me, that would be 12 v1.0 launches = 36 planes with (almost) 20 satellites per plane. Current satellite deployment is such that if everything on orbit finished raising, there would be a gap of 3 planes, a gap of 2 planes and a gap of 1 plane. This implies 1 extra launch required to get to the right positions quickly for 13 launches. Then launching in order from 3 plane gap to 2 plane to 1 plane, to minimize drifting time before a set of 36 equal spaced planes is complete. If launches happen quick enough, the last plane worth from L11 can have its spot taken by L14 satellites, while the remaining L11 either stop drifting half a plane early to start the next level of plane density, or be used to start filling in planes to the final plan of a full 22 satellites per plane.

In conclusion 12 launch groups = 13-14 launches = 36 planes.

* in case anyone missed it this "easy" is slightly sarcastic, given all of the slightly strange steps such as 12 launches = 13 launches

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Re: Starlink : General Discussion - Thread 2
« Reply #1756 on: 08/22/2020 12:20 am »
All this discussion about how many is 800 is interesting, but I thought the more interesting part was:

Quote
Company officials said service will be offered in northern portions of the United States and Canada after 12 satellite fleet deployments,

Now that should give us something more interesting to quibble about! How many are 12?
That seems easy* to me, that would be 12 v1.0 launches = 36 planes with (almost) 20 satellites per plane. Current satellite deployment is such that if everything on orbit finished raising, there would be a gap of 3 planes, a gap of 2 planes and a gap of 1 plane. This implies 1 extra launch required to get to the right positions quickly for 13 launches. Then launching in order from 3 plane gap to 2 plane to 1 plane, to minimize drifting time before a set of 36 equal spaced planes is complete. If launches happen quick enough, the last plane worth from L11 can have its spot taken by L14 satellites, while the remaining L11 either stop drifting half a plane early to start the next level of plane density, or be used to start filling in planes to the final plan of a full 22 satellites per plane.

In conclusion 12 launch groups = 13-14 launches = 36 planes.

* in case anyone missed it this "easy" is slightly sarcastic, given all of the slightly strange steps such as 12 launches = 13 launches

Oh good answer! That means they will soon be generating revenue with the 3, 2, 1 plane countdown on the way to 22.

Seriously, to me, "service will be offered" implies that there will be a charge. Does anyone agree with that or will the service be free? And if there is a charge, then Starlink should start generating revenue in a month or so. For some reason, I have always thought of Starlink as a service available sometime in the future, not in just a few days.
« Last Edit: 08/22/2020 12:20 am by aero »
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Online gongora

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Re: Starlink : General Discussion - Thread 2
« Reply #1757 on: 08/22/2020 12:39 am »
Starlink will not be offering paid service in a month.  They're early in beta testing.

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Re: Starlink : General Discussion - Thread 2
« Reply #1758 on: 08/22/2020 02:26 am »
There have been slightly varying numbers given for deployment milestones over the years, and I think some of them need some additional detail to understand what it really meant. 

For coverage over the northern US/southern Canada, evenly spacing the satellites from 6 launches over 18 planes would give initial coverage.  The way the deployment unfolded, to speed things up a little they didn't spread the satellites evenly from some launches and are using more than 6 launches to get those 18 planes, but that is close to happening now.

With 12 fully deployed launches they should get coverage of most of the US.  Fully deploying the satellites after launch can be 3-4 months.

Gwynne tossed out a number of 14 launches earlier this year before they would start promoting the service.  I'm not entirely sure if that meant 1) after 14 launches, at about two a month, the satellites from the first 6-8 launches would be in their final planes and able to serve the northern US when that 14th launch happened or 2) after 14 launches are fully deployed they can start promoting it to most of the US.

When they get all of the initial deployment (~1400 satellites) done then they'll have coverage from a bit under 60 degrees latitude down to the equator, which SpaceX often calls "global" coverage.  It obviously isn't global, but covers most of the population of the world.  To get coverage of the whole planet they'll need to launch their higher inclination planes.  Those higher inclination planes are currently authorized to be at 1000km+ in altitude.  SpaceX has applied to lower them to under 600km, and probably doesn't want to start messing with those planes until their application is resolved one way or the other, but that resolution should happen before they finish the initial 1400 sat deployment.

Offline OTV Booster

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Re: Starlink : General Discussion - Thread 2
« Reply #1759 on: 08/22/2020 04:00 pm »
All this discussion about how many is 800 is interesting, but I thought the more interesting part was:

Quote
Company officials said service will be offered in northern portions of the United States and Canada after 12 satellite fleet deployments,

Now that should give us something more interesting to quibble about! How many are 12?
That seems easy* to me, that would be 12 v1.0 launches = 36 planes with (almost) 20 satellites per plane. Current satellite deployment is such that if everything on orbit finished raising, there would be a gap of 3 planes, a gap of 2 planes and a gap of 1 plane. This implies 1 extra launch required to get to the right positions quickly for 13 launches. Then launching in order from 3 plane gap to 2 plane to 1 plane, to minimize drifting time before a set of 36 equal spaced planes is complete. If launches happen quick enough, the last plane worth from L11 can have its spot taken by L14 satellites, while the remaining L11 either stop drifting half a plane early to start the next level of plane density, or be used to start filling in planes to the final plan of a full 22 satellites per plane.

In conclusion 12 launch groups = 13-14 launches = 36 planes.

* in case anyone missed it this "easy" is slightly sarcastic, given all of the slightly strange steps such as 12 launches = 13 launches
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