Starlink ruining the night sky

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RandomElement
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Starlink ruining the night sky

Post by RandomElement » Sat Nov 23, 2019 7:36 pm

Branching off from EPD's "The future of the environment, capitalism & human rights" thread, I didn't know about starlink and what it affects, but having a quick read around it quite concerning and I thought it's worth it's own thread.

Starlink is planned to a constellation of 12,000 satellites by the mid 2020s and possibly up to 42,000 at the moment the satellites have a high reflectivity and are concerning to astronomers and radio-astronomers. The The International Astronomical Union and National Radio Astronomy Observatory have both given statements expressing concern.
Also what effect will have have on animals that use stars to navigate?


https://www.forbes.com/sites/startswith ... f1754e4ccc
SpaceX already seem to be taking a F.U. attidude.
Already, back in September, the ESA's Aeolus satellite (used for Earth observation) had to make an emergency maneuver to avoid colliding with a SpaceX Starlink satellite, despite the fact that it was SpaceX's responsibility to move.

Although SpaceX and Musk have issued statements claiming that:

the satellites will have minimum impact on astronomy,
SpaceX will work on reducing the albedo of these satellites,
and Starlink will provide on-demand orientation adjustments for astronomical experiments,
all of these statements are not yet true as of November 20, 2019.
Also https://www.youtube.com/watch?v=oHs7ljhQWPA from about 2:11
spaceweather.com wrote:Earth grazed a filament of comet dust, prompting a flurry of meteors from Monoceros the Unicorn. In La Palma on the Canary islands, a Global Meteor Network camera captured the display--and something more. Starlink photobombed the meteor shower
We may the last people to see the night sky as it should be for a long time.

Gawdzilla Sama
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Re: Starlink ruining the night sky

Post by Gawdzilla Sama » Sat Nov 23, 2019 9:03 pm

12,000 new stars. How many can be seen from any one place on Earth? How many of them don't move, geostationary orbit? How many people will be fooled by a few new stars? (Maybe just the ones that need to get lost anyway?) :lol:

RandomElement
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Re: Starlink ruining the night sky

Post by RandomElement » Sat Nov 23, 2019 9:39 pm

These are going to be in low earth orbit about 500km plus due to the current reflectivity they will be brighter than stars people can see in darksky locations.

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Re: Starlink ruining the night sky

Post by Gawdzilla Sama » Sun Nov 24, 2019 10:12 am

People going to be hopelessly confused or people going to learn to sort? Or both?

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GeenDienst
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Re: Starlink ruining the night sky

Post by GeenDienst » Sun Nov 24, 2019 10:40 am

Maybe he should meet us half way and arrange them into arrays spelling out pleasingly rude words.
Just tell 'em I'm broke and don't come round here no more.

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Sciolus
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Re: Starlink ruining the night sky

Post by Sciolus » Sun Nov 24, 2019 11:06 am

Presumably if they are in low earth orbit they will only be visible at relatively low altitudes, where stars are generally harder to see.

How does their brightness compare to aircraft lights?

But yeah, f.cking global pollution.

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Martin Y
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Re: Starlink ruining the night sky

Post by Martin Y » Sun Nov 24, 2019 11:10 am

GeenDienst wrote:
Sun Nov 24, 2019 10:40 am
Maybe he should meet us half way and arrange them into arrays spelling out pleasingly rude words.
I was wondering if he might like the idea of building a gigantic digital clock on the moon. He'd do it if the display could be switched to say "80085".

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Martin Y
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Re: Starlink ruining the night sky

Post by Martin Y » Sun Nov 24, 2019 11:14 am

Sciolus wrote:
Sun Nov 24, 2019 11:06 am
Presumably if they are in low earth orbit they will only be visible at relatively low altitudes, where stars are generally harder to see.

How does their brightness compare to aircraft lights?

But yeah, f.cking global pollution.
I'm not following you. Low earth orbiting satellites are already around, though not in such numbers, and you can watch them pass overhead if you just stare at the night sky for a while. At 500km altitude you'll only see them when they get within a few hundred km of your location but they'll appear to fly right over your head in the course of a minute or two.

Oh, wait, you mean they'll only be visible in sunlight so only at dusk. Hmm. Maybe, but I've watched GPS (or whatever) satellites go over on Summer evenings when it was quite dark enough to do a drunk guide to the constellations with friends.

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Sciolus
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Re: Starlink ruining the night sky

Post by Sciolus » Sun Nov 24, 2019 11:20 am

Because most of the time they'll be in earth's shadow. You wouldn't be able to see them directly overhead at midnight, for example.

Edit: crossedited? Anyway, I stand to be corrected.

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Martin Y
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Re: Starlink ruining the night sky

Post by Martin Y » Sun Nov 24, 2019 11:50 am

I let the internet hold my hand while it did some sums. At 500km altitude your horizon is 2,500 km away, which is neatly 1/16 the earth's circumference, so (on the equator) you'd be in sunlight for an hour and a half after local sunset and before sunrise. Longer at higher latitudes but <shrug> sums, eh? I mean "I leave that as an exercise for the reader".

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Re: Starlink ruining the night sky

Post by shpalman » Sun Nov 24, 2019 11:56 am

Martin Y wrote:
Sun Nov 24, 2019 11:14 am
Sciolus wrote:
Sun Nov 24, 2019 11:06 am
Presumably if they are in low earth orbit they will only be visible at relatively low altitudes, where stars are generally harder to see.

How does their brightness compare to aircraft lights?

But yeah, f.cking global pollution.
I'm not following you. Low earth orbiting satellites are already around, though not in such numbers, and you can watch them pass overhead if you just stare at the night sky for a while. At 500km altitude you'll only see them when they get within a few hundred km of your location but they'll appear to fly right over your head in the course of a minute or two.

Oh, wait, you mean they'll only be visible in sunlight so only at dusk. Hmm. Maybe, but I've watched GPS (or whatever) satellites go over on Summer evenings when it was quite dark enough to do a drunk guide to the constellations with friends.
GPS satellites are higher up so that the orbit is 12 hours.
molto tricky

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Re: Starlink ruining the night sky

Post by Gawdzilla Sama » Sun Nov 24, 2019 12:33 pm

Engage Chicken Little mode!

Image

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Martin Y
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Re: Starlink ruining the night sky

Post by Martin Y » Sun Nov 24, 2019 12:51 pm

PS I think at UK latitudes these satellites will still be in sunlight around 2.5 hours after sunset. But I wouldn't trust me.

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Re: Starlink ruining the night sky

Post by dyqik » Sun Nov 24, 2019 12:53 pm

Martin Y wrote:
Sun Nov 24, 2019 12:51 pm
PS I think at UK latitudes these satellites will still be in sunlight around 2.5 hours after sunset. But I wouldn't trust me.
At least that.

And remember, some of us view the night sky in, or close to the bands where they are transmitting from these satellites, and in the thermal infrared. These satellites will be ~290K against a cold background.

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Re: Starlink ruining the night sky

Post by username » Sun Nov 24, 2019 12:58 pm

Just a quick info injection, there are I think 4 competing constellation programs, two of which have launched prototypes (oneweb and starlink). Oneweb is testing in Korea and only has 6 satellites up so far. Main point I'm making is that any problems extend beyond starlink.
The half-truths, repeated, authenticated themselves.

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Martin Y
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Re: Starlink ruining the night sky

Post by Martin Y » Sun Nov 24, 2019 1:12 pm

Aside from the immediate impact, we're creating an awful lot of future space junk. How realistic is the nightmare that we maroon ourselves by making space flight too dangerous, rather like Easter Islanders trapped with no trees left to build boats?

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Re: Starlink ruining the night sky

Post by username » Sun Nov 24, 2019 1:55 pm

Proposed constellations have obsolescence built in. Low orbit means the nodes will drop and burn up in the atmosphere as their orbit degrades due to atmospheric drag.

To date the vast majority of the 128 million pieces of space junk have been a direct result of government space programs.
The half-truths, repeated, authenticated themselves.

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Gfamily
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Re: Starlink ruining the night sky

Post by Gfamily » Sun Nov 24, 2019 3:15 pm

If you consider small orbiting objects as bullets and large objects as targets that will turn into bullets if impacted, there are currently c4500 targets & 35000 artillery shells (>10cm) and however many bullets as mentioned above.

Starlink is proposing tripling the number of targets.
The potential exists to make low earth orbit a minefield, and inaccessible to satellites of any type.

That's my main concern, though as an amateur astronomer I am also disturbed by the potential for wrecking astro imaging, whether amateur or professional.
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Re: Starlink ruining the night sky

Post by Gawdzilla Sama » Sun Nov 24, 2019 3:33 pm

Maybe they should orbit them so they make a big Jaffa cake in the sky...

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GeenDienst
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Re: Starlink ruining the night sky

Post by GeenDienst » Sun Nov 24, 2019 4:32 pm

Gawdzilla Sama wrote:
Sun Nov 24, 2019 3:33 pm
Maybe they should orbit them so they make a big Jaffa cake in the sky...
Like a massive sky biscuit?
Just tell 'em I'm broke and don't come round here no more.

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Re: Starlink ruining the night sky

Post by Gawdzilla Sama » Sun Nov 24, 2019 4:37 pm

GeenDienst wrote:
Sun Nov 24, 2019 4:32 pm
Gawdzilla Sama wrote:
Sun Nov 24, 2019 3:33 pm
Maybe they should orbit them so they make a big Jaffa cake in the sky...
Like a massive sky biscuit?
Don't call it that. My hillbilly cousins would try to drown it in sausage gravy. :?

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Re: Starlink ruining the night sky

Post by bolo » Sun Nov 24, 2019 5:35 pm

Gfamily, I don't know where you're getting your numbers, but I think the current number of operational satellites is closer to 2000, and the number of tracked objects larger than 10cm is closer to 17,000.

Some useful data here:
https://planet4589.org/space/log/stats1.html

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Re: Starlink ruining the night sky

Post by username » Sun Nov 24, 2019 6:05 pm

I was wondering how densely populated an orbital shell containing 12000 LEO satellites would be.

By my calculations at an altitude of 500km, 12000 equally spaced satellites would get you 1 satellite per 48500 square kilometers. On the ISO scale that's a little over two Waleses per satellite.

I know they're moving about etc. but I certainly struggle with the scale of this stuff (hhgttg quotation goes here :) ).
The half-truths, repeated, authenticated themselves.

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Gfamily
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Re: Starlink ruining the night sky

Post by Gfamily » Sun Nov 24, 2019 6:22 pm

bolo wrote:
Sun Nov 24, 2019 5:35 pm
Gfamily, I don't know where you're getting your numbers, but I think the current number of operational satellites is closer to 2000, and the number of tracked objects larger than 10cm is closer to 17,000.

Some useful data here:
https://planet4589.org/space/log/stats1.html
That's operational satellites.
The wiki says
According to a 2018 estimate, some 5,000 remain in orbit. Of those about 1,900 were operational, while the rest have lived out their useful lives and become space debris.
I can't remember where I heard the 40K figure for >10cm debris.
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Re: Starlink ruining the night sky

Post by bolo » Sun Nov 24, 2019 6:31 pm

I took your word "targets" to mean operational, but looking back I see you didn't actually say that. My mistake.

According to one of dyqik's colleagues who gave a talk at my workplace last week, if Starlink is fully built out, on a dark night, the naked eye will see more Starlink satellites than stars.

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