These companies all want sun-synchronous terminator orbits, so that they can be sunlit all the time*.
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These companies all want sun-synchronous terminator orbits, so that they can be sunlit all the time*. Sun-synchronous orbits have a nodal precession rate that matches Earth's orbit period around the sun. Meaning, they keep the same configuration relative to local daytime. If the satellite passes over the equator where it is 6pm directly under the satellite, it will always do that.
*important problem with this assumption coming later in the thread
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These companies all want sun-synchronous terminator orbits, so that they can be sunlit all the time*. Sun-synchronous orbits have a nodal precession rate that matches Earth's orbit period around the sun. Meaning, they keep the same configuration relative to local daytime. If the satellite passes over the equator where it is 6pm directly under the satellite, it will always do that.
*important problem with this assumption coming later in the thread
We model 3 different configurations that 5 different companies have asked for variations on. An "X-ring", where both possible nodes are used, so you get one orbit tilted at ~98 degrees (depending on inclination) and the other tiled at ~82 degrees. They make an X over the equator. There's also "X-ring plus orbital shell" which is whatever the fuck SpaceX asked for with their million satellite filing. And a single ring, which is self-explanatory.
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Just thinking about this - does filling the sky with these satellites make locating/tracking large asteroids on possible collision course with earth more difficult?
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We model 3 different configurations that 5 different companies have asked for variations on. An "X-ring", where both possible nodes are used, so you get one orbit tilted at ~98 degrees (depending on inclination) and the other tiled at ~82 degrees. They make an X over the equator. There's also "X-ring plus orbital shell" which is whatever the fuck SpaceX asked for with their million satellite filing. And a single ring, which is self-explanatory.
Next we have to make wild assumptions about the size of the satellites, because all of these companies have no idea what the fuck they are doing (and orbital data centers might not even be physically possible), so they haven't actually provided any solid info on how big they are. We are guessing from sketches posted on twitter, basically. SpaceX is ~800m^2 of reflective solar panel, so we use that for every company.
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Next we have to make wild assumptions about the size of the satellites, because all of these companies have no idea what the fuck they are doing (and orbital data centers might not even be physically possible), so they haven't actually provided any solid info on how big they are. We are guessing from sketches posted on twitter, basically. SpaceX is ~800m^2 of reflective solar panel, so we use that for every company.
A completely fucking ridiculous drawing in an FCC filing from Cowboy space (I did a thread about that last week, https://mastodon.social/@sundogplanets/117009754043091268) indicates they might have a reflecting area of 4800 m^2. WAY BIGGER than the ISS, the biggest thing ever placed in orbit, in pieces, not as one monolith. These companies are just making shit up. For comparison's sake, we just use 800m^2 for every simulation.
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We model 3 different configurations that 5 different companies have asked for variations on. An "X-ring", where both possible nodes are used, so you get one orbit tilted at ~98 degrees (depending on inclination) and the other tiled at ~82 degrees. They make an X over the equator. There's also "X-ring plus orbital shell" which is whatever the fuck SpaceX asked for with their million satellite filing. And a single ring, which is self-explanatory.
One ring to rule them all.
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A completely fucking ridiculous drawing in an FCC filing from Cowboy space (I did a thread about that last week, https://mastodon.social/@sundogplanets/117009754043091268) indicates they might have a reflecting area of 4800 m^2. WAY BIGGER than the ISS, the biggest thing ever placed in orbit, in pieces, not as one monolith. These companies are just making shit up. For comparison's sake, we just use 800m^2 for every simulation.
Here is the link to the first post of the thread, if that helps:
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A completely fucking ridiculous drawing in an FCC filing from Cowboy space (I did a thread about that last week, https://mastodon.social/@sundogplanets/117009754043091268) indicates they might have a reflecting area of 4800 m^2. WAY BIGGER than the ISS, the biggest thing ever placed in orbit, in pieces, not as one monolith. These companies are just making shit up. For comparison's sake, we just use 800m^2 for every simulation.
And then we make a silly but useful assumption. We are very honest about this, the section is titled "All models are wrong, some are useful"
We say that all satellites are spheres. Obviously, this is not true. But it provides a good comparison point. And without completely detailed, perfect info about the shape and materials of every satellite in orbit, we can't actually do a better job of this, and this actually does a good job of reproducing Starlink brightnesses. So, spherical cow it is.
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A completely fucking ridiculous drawing in an FCC filing from Cowboy space (I did a thread about that last week, https://mastodon.social/@sundogplanets/117009754043091268) indicates they might have a reflecting area of 4800 m^2. WAY BIGGER than the ISS, the biggest thing ever placed in orbit, in pieces, not as one monolith. These companies are just making shit up. For comparison's sake, we just use 800m^2 for every simulation.
@sundogplanets and the ISS is already so bright! It's somewhat magical to watch it « swoosh » silently in the sky.
Still have fond memories of it happening while I was on schoolbus back from high school 
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And then we make a silly but useful assumption. We are very honest about this, the section is titled "All models are wrong, some are useful"
We say that all satellites are spheres. Obviously, this is not true. But it provides a good comparison point. And without completely detailed, perfect info about the shape and materials of every satellite in orbit, we can't actually do a better job of this, and this actually does a good job of reproducing Starlink brightnesses. So, spherical cow it is.
And then, we confirm something that Hugh Lewis posted previously (sorry for Linkedin, that's where it is https://www.linkedin.com/pulse/sun-always-shines-tv-hugh-lewis-tlkbe)
These orbits don't actually stay sunlit all the time! Unless you're above something like 1400km altitude, these sun-synchronous terminator orbits will pass through Earth's shadow at some times of year. That means your data center will have to turn off every 90 min, or have huge batteries. You can't have 24hour sunlight AND low altitude, low-latency orbits.
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A completely fucking ridiculous drawing in an FCC filing from Cowboy space (I did a thread about that last week, https://mastodon.social/@sundogplanets/117009754043091268) indicates they might have a reflecting area of 4800 m^2. WAY BIGGER than the ISS, the biggest thing ever placed in orbit, in pieces, not as one monolith. These companies are just making shit up. For comparison's sake, we just use 800m^2 for every simulation.
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And then, we confirm something that Hugh Lewis posted previously (sorry for Linkedin, that's where it is https://www.linkedin.com/pulse/sun-always-shines-tv-hugh-lewis-tlkbe)
These orbits don't actually stay sunlit all the time! Unless you're above something like 1400km altitude, these sun-synchronous terminator orbits will pass through Earth's shadow at some times of year. That means your data center will have to turn off every 90 min, or have huge batteries. You can't have 24hour sunlight AND low altitude, low-latency orbits.
@sundogplanets I read that as Huey Lewis and was wondering when he'd drifted into this field...
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And then, we confirm something that Hugh Lewis posted previously (sorry for Linkedin, that's where it is https://www.linkedin.com/pulse/sun-always-shines-tv-hugh-lewis-tlkbe)
These orbits don't actually stay sunlit all the time! Unless you're above something like 1400km altitude, these sun-synchronous terminator orbits will pass through Earth's shadow at some times of year. That means your data center will have to turn off every 90 min, or have huge batteries. You can't have 24hour sunlight AND low altitude, low-latency orbits.
Here's the future that the techbros want. Earth as a ringed planet.
What does that actually look like in the sky? Well, it depends on your latitude and the time of year. The worst time of year for sunlit Starlink satellites is summer, but due to these orbits, the worst time for sunlit sun-synchronous terminator orbits is actually the wintertime.
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Here's the future that the techbros want. Earth as a ringed planet.
What does that actually look like in the sky? Well, it depends on your latitude and the time of year. The worst time of year for sunlit Starlink satellites is summer, but due to these orbits, the worst time for sunlit sun-synchronous terminator orbits is actually the wintertime.
And then there are a bunch of horrifying sky diagrams. Please take a look at the paper if you want to see those! I will share the extra movies here.
First, Cowboy "Stampede" (my goodness I hate these names), a single ring. This is the view from 30N on the winter solstice. You can even see in the movie how part of the ring is not sunlit. There is also a histogram showing the brightness of satellites and stars: for a lot of the time the ring is up, there are more bright sats than stars.
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And then there are a bunch of horrifying sky diagrams. Please take a look at the paper if you want to see those! I will share the extra movies here.
First, Cowboy "Stampede" (my goodness I hate these names), a single ring. This is the view from 30N on the winter solstice. You can even see in the movie how part of the ring is not sunlit. There is also a histogram showing the brightness of satellites and stars: for a lot of the time the ring is up, there are more bright sats than stars.
Now Blue Origin's "Sunrise" which has the X-ring configurations. Here's from 30N on the winter solstice.
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Now Blue Origin's "Sunrise" which has the X-ring configurations. Here's from 30N on the winter solstice.
From the equator, you'd see the X directly overhead at 6pm. Lovely.
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Here's the future that the techbros want. Earth as a ringed planet.
What does that actually look like in the sky? Well, it depends on your latitude and the time of year. The worst time of year for sunlit Starlink satellites is summer, but due to these orbits, the worst time for sunlit sun-synchronous terminator orbits is actually the wintertime.
Kessler Syndrome Here We Come!
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From the equator, you'd see the X directly overhead at 6pm. Lovely.
@sundogplanets and that is not even taking into consideration the damage such satellite constellations do to the atmosphere. Just the few tons of aluminum starlink is dumping into the atmosphere are already a big source of concern, 800m*m armatures raining from the sky sounds like what disaster movies are made of
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From the equator, you'd see the X directly overhead at 6pm. Lovely.
From the far north (or far south), you'd see one of the rings continuously, all through the long winter night (which could be 24 hours of darkness and near-darkness). But the satellites will keep you company! Ugh. Gross. There would be more bright satellites than bright stars, all night long.
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@sundogplanets and that is not even taking into consideration the damage such satellite constellations do to the atmosphere. Just the few tons of aluminum starlink is dumping into the atmosphere are already a big source of concern, 800m*m armatures raining from the sky sounds like what disaster movies are made of
@sundogplanets ah I see you mentioned it in the conclusion! Nice!
