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27-12-2019, 11:51 AM
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Satellite constellations - A threat to Earth's view of the Universe

https://www.bbc.co.uk/news/science-environment-50870117



From next week, a campaign to launch thousands of new satellites will begin in earnest, offering high-speed internet access from space. Instead of being constrained by wires and cables, satellites can beam internet access down to the ground from space. And if you have lots of them in orbit, it means even the most remote regions can get connectivity.

To give you an idea of the numbers, there are currently just 2,200 active satellites flying around the Earth. But as of next week, the Starlink constellation - a project by US company SpaceX - will start sending batches of 60 satellites into orbit every few weeks. This will mean about 1,500 satellites have been launched by the end of next year, and by the mid-2020s there could be a fleet of 12,000. UK company OneWeb are aiming for about 650 satellites - but this could rise to 2,000 if there is enough customer demand. While Amazon have a constellation of 3,200 spacecraft planned.

In May and November, Starlink sent 120 satellites into orbits below 500km. Stargazers were concerned when the spacecraft appeared as bright white flashes on their images. Scientists are worried that future "mega-constellations" of satellites could obscure images from optical telescopes and interfere with radio astronomy observations.

Dhara Patel, an astronomer at the Royal Observatory Greenwich said: "These satellites are about the size of a table, but they're very reflective, and their panels reflect lots of the Sun's light, which means that we can see them in images that we take with telescopes. These satellites are also big radiowave users… and that means they can interfere with the signals that astronomers using. So it also affects radio astronomy as well."
So, a planned 15,000 satellites to add to the existing 100,000+ man-made objects already circling the Earth - it's getting mighty crowded .....
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27-12-2019, 12:29 PM
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Re: Satellite constellations - A threat to Earth's view of the Universe

I heard about that Omar and it is worrying.
Coating the satellites with a none reflective material has been mentioned but that might affect their performance.
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27-12-2019, 12:36 PM
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Re: Satellite constellations - A threat to Earth's view of the Universe

Originally Posted by Omah ->
https://www.bbc.co.uk/news/science-environment-50870117





So, a planned 15,000 satellites to add to the existing 100,000+ man-made objects already circling the Earth - it's getting mighty crowded .....
Time for some co -ordinated controls on satullite launches l think
Omah?It seems any tom, dick, or harry can dump their junk how
they see fit!
Donkeyman!
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27-12-2019, 12:54 PM
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Re: Satellite constellations - A threat to Earth's view of the Universe

Originally Posted by Meg ->
I heard about that Omar and it is worrying.
Coating the satellites with a none reflective material has been mentioned but that might affect their performance.
A non-reflective coating might hide the reflection from satellites but would still hide what's behind the satellite - "a nearby potentially hazardous asteroid or the most distant Quasar in the Universe" .....
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27-12-2019, 12:59 PM
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Re: Satellite constellations - A threat to Earth's view of the Universe

Originally Posted by Donkeyman ->
Time for some co -ordinated controls on satullite launches l think
Omah?It seems any tom, dick, or harry can dump their junk how
they see fit!
Donkeyman!
Russia and China have been setting up their own internet services - the latter with money to burn - the anticipated number of satellites could easily triple .....
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27-12-2019, 01:12 PM
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Re: Satellite constellations - A threat to Earth's view of the Universe

Originally Posted by Omah ->
Russia and China have been setting up their own internet services - the latter with money to burn - the anticipated number of satellites could easily triple .....
Maybe it will cancel out global warming by interfering with
sunlight?? We are sooo clever??

Donkeyman!
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27-12-2019, 01:19 PM
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Re: Satellite constellations - A threat to Earth's view of the Universe

Thanks for posting this news Omah, and there probably are going to be problems especially when they eventually fall back to earth, and they will!
However......
How many aeroplanes are in the skies at any one time..? I estimate more than a hundred times more than the total amount of satellites.

And the trouble with graphics like this is....If it was to scale the size of each satellite would be so small that you wouldn't even see it with the naked eye....

We sometimes forget how big this planet and its surrounding atmosphere really is..
Something all too often neglected when discussing man made climate change.
Transport that can whisk you to the other side of the world in 24 hours, or skype etc that can beam pictures of your loved ones around the world in real time certainly make the world look small.

But if you were to travel in space amongst all these satellites you might be lucky to spot one all day, they would be that far apart.....
Consider the Atlantic ocean, a million times smaller than satellite territory, and the amount of shipping present on it (thousands of craft) and yet you can sail for three or more days without spotting one vessel....
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27-12-2019, 01:37 PM
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Re: Satellite constellations - A threat to Earth's view of the Universe

Originally Posted by OldGreyFox ->
How many aeroplanes are in the skies at any one time..? I estimate more than a hundred times more than the total amount of satellites.
.

Apparently:

https://www.rd.com/advice/travel/how...re-in-the-sky/

Depending on the time of day or time of year, there could be anywhere from 8,000 to 20,000 planes mid-flight at any given moment, according to Flightradar24, which keeps track of flights in real time. You’re most likely to find numbers on the high end of that range in the summer when it’s between 2 p.m. and 4 p.m. Western European Time because at that point, flights in North America (where it will be morning) and Europe (where it will be afternoon or early evening) will be active, the analysts say. Typically, the year’s busiest flight day is in July or August on a Thursday or Friday.
That's a lot less than I thought but that amounts to anywhere between 100,000 and 200,000 flights per day, including private, business and military aviation.
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27-12-2019, 01:52 PM
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Re: Satellite constellations - A threat to Earth's view of the Universe

Originally Posted by OldGreyFox ->
But if you were to travel in space amongst all these satellites you might be lucky to spot one all day, they would be that far apart......
Good point …..

But then there's orbital debris:

https://www.nasa.gov/mission_pages/s...al_debris.html



Orbital debris is any man-made object in orbit about the Earth which no longer serves a useful function. Such debris includes nonfunctional spacecraft, abandoned launch vehicle stages, mission-related debris and fragmentation debris.

There are more than 20,000 pieces of debris larger than a softball orbiting the Earth. They travel at speeds up to 17,500 mph, fast enough for a relatively small piece of orbital debris to damage a satellite or a spacecraft. There are 500,000 pieces of debris the size of a marble or larger. There are many millions of pieces of debris that are so small they can’t be tracked.

Even tiny paint flecks can damage a spacecraft when traveling at these velocities. In fact a number of space shuttle windows have been replaced because of damage caused by material that was analyzed and shown to be paint flecks.

“The greatest risk to space missions comes from non-trackable debris,” said Nicholas Johnson, NASA chief scientist for orbital debris
"Many millions" is a lot more than I thought …..
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27-12-2019, 02:20 PM
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Re: Satellite constellations - A threat to Earth's view of the Universe

Whilst l agree with you generally OGF, l differ when it comes to
this p!anets atmosphere, lf you see the planet from space the
depth of the atmosphere compared to the size of the planet you will
see that it seems to be very thin in relation to the globe, in fact it
looks very mimimal and vulnerable? So l do believe it may be
possible for us, especially as we proliferate, to have some sort of
influence on it? However l keep an open mind on whether we can
compete with the forces of nature!
Donkeyman!
 
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