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TeraWave Satellite Communications Network

blueorigin.com

81–90 of 116 posts

Re: TeraWave Satellite Communications Network

#81

Earlier quoted context omitted.

Orbits are predictable, but they intersect and decay [at different rates] and occasionally get perturbed by space weather. This already needs periodic conjunction avoidance manoeuvres, and whilst orbits are fast satellite manoeuvres are slow , so the notice you need to avoid a conjunction is measured in hours rather than seconds. Can't imagine a scenario in which it would be sustainable for LEO to even approach the d…

> and whilst orbits are fast satellite manoeuvres are slow This is something people unfamiliar tend to misconceive in their limited thinking on the subject. You can't just tap the breaks to slow down. Changing altitude of satellites is done by speeding up to increase altitude and slowing down to lower altitude. Once you change the velocity and reach the desired altitude, you have to then undo that acceleration to get…

> This is something people unfamiliar tend to misconceive in their limited thinking on the subject

I have a background in astronautical engineering. While you can't tap the brakes to 'slow down', you can impart miniscule amounts of impulse which, over the course of hundreds of orbits, will change your plane by an imperceptible amount from a distance, but tens or hundreds of kilometers up close. OM being OM, you can predicts these collisions in advance.

I had a professor who referred to orbits not in altitude but in expected decay time. We're currently in the months to single-digit years orbits. (We will stay there for telecommunications due to latency.) If we were doing at decades or centuries what we're doing in LEO, this would be a problem. At LEO, it's a nuisance and barely more.

Re: TeraWave Satellite Communications Network

#82

Earlier quoted context omitted.

Orbits are predictable, but they intersect and decay [at different rates] and occasionally get perturbed by space weather. This already needs periodic conjunction avoidance manoeuvres, and whilst orbits are fast satellite manoeuvres are slow , so the notice you need to avoid a conjunction is measured in hours rather than seconds. Can't imagine a scenario in which it would be sustainable for LEO to even approach the d…

> whilst orbits are fast satellite manoeuvres are slow, so the notice you need to avoid a conjunction is measured in hours rather than seconds I'm not arguing against collisions becoming more likely. I'm arguing aginst it becoming commonplace to the point that it becomes a commercial concern. > satellite manoeuvres use up a finite supply of expensively-launched propellant Nobody is plane changing out of a collision.…

> e.g. magnetic station-keeping

I've not kept up for decades now .. what's the state of solar powered magnetorquers these days? I'd quietly assumed it would be more commonplace.

I dimly recall a couple of small satellites magnetically locking fifteen or so years past?

Re: TeraWave Satellite Communications Network

#83
It’s like announcing you’re going to sell corn starting a year from now when your competition owns all the land corn is grown on, started selling their corn 6 years ago, and has gotten really good at making it cheaper and producing more, based on real world experience.

Re: TeraWave Satellite Communications Network

#84

Earlier quoted context omitted.

> and whilst orbits are fast satellite manoeuvres are slow This is something people unfamiliar tend to misconceive in their limited thinking on the subject. You can't just tap the breaks to slow down. Changing altitude of satellites is done by speeding up to increase altitude and slowing down to lower altitude. Once you change the velocity and reach the desired altitude, you have to then undo that acceleration to get…

> This is something people unfamiliar tend to misconceive in their limited thinking on the subject I have a background in astronautical engineering. While you can't tap the brakes to 'slow down', you can impart miniscule amounts of impulse which, over the course of hundreds of orbits, will change your plane by an imperceptible amount from a distance, but tens or hundreds of kilometers up close. OM being OM, you can p…

> you can impart miniscule amounts of impulse which, over the course of hundreds of orbits

right. this is what is counter-intuitive for those that are not familiar with space. they don't just light the burner and boost to a new altitude. the part about stopping the acceleration with an opposite burn is often not considered. most think you can fly a space ship like a jet fighter, but in space. can't blame them since that's how sci-fi portrays it. real life space flight is really boring in comparison. jumping out of FTL to land in orbit around a planet makes me laugh every. single. time.

Re: TeraWave Satellite Communications Network

#85

Earlier quoted context omitted.

Even if these sats do collide and produce debris, they are in decaying orbits, so that stuff will eventually fall back down.

Debris moves in 3D. Debris moving up will continue moving up. There is no force acting on it to bring it back down. Your comment makes it sound like an explosion would only be in 2D along the same orbit as the original object.

> There is no force acting on it to bring it back down.

Gravity?

But also orbital dynamics (at least as I understand it) means debris that debris that is flung up is going to have a more oval orbit, so the high point (apogee) increases and the low point (perigee) decreases. And a lower perigee means more atmospheric drag, which will help deorbit the debris.

Re: TeraWave Satellite Communications Network

#86
post #85

Earlier quoted context omitted.

Debris moves in 3D. Debris moving up will continue moving up. There is no force acting on it to bring it back down. Your comment makes it sound like an explosion would only be in 2D along the same orbit as the original object.

> There is no force acting on it to bring it back down. Gravity? But also orbital dynamics (at least as I understand it) means debris that debris that is flung up is going to have a more oval orbit, so the high point (apogee) increases and the low point (perigee) decreases. And a lower perigee means more atmospheric drag, which will help deorbit the debris.

That'd have to be one slow explosion to give it less than 1G of acceleration.

Re: TeraWave Satellite Communications Network

#87

Earlier quoted context omitted.

Even if these sats do collide and produce debris, they are in decaying orbits, so that stuff will eventually fall back down.

Debris moves in 3D. Debris moving up will continue moving up. There is no force acting on it to bring it back down. Your comment makes it sound like an explosion would only be in 2D along the same orbit as the original object.

That is not how orbital mechanics work.

It may seem counterintuitive, but if something in orbit gets a push that isn’t strong enough to make it totally escape orbit, it will stay in a new elliptical orbit. That new orbit will pass through the point where the push happened, so it will come back through that location again, just with a different speed and direction.

Re: TeraWave Satellite Communications Network

#88
post #3

Earlier quoted context omitted.

Some info from NASA optical communication page. "Even Earth’s atmosphere interferes with optical communications. Clouds and mist can interrupt a laser. A solution to this is building multiple ground stations, which are telescopes on Earth that receive infrared waves. If it’s cloudy at one station, the waves can be redirected to a different ground station. With more ground stations, the network can be more flexible du…

Seems like reusing some of Star Wars research could be used as well where the beam is constantly adjusted with independent mirrors to keep the beam coherent through the atmosphere. Also learned was the beam itself starts to distort the atmosphere requiring even more adjustments.

>the beam itself starts to distort the atmosphere requiring even more adjustments.

may be something like this - a high-power impulse making a channel through whatever clouds, mist, dust and after that information carrying ray/impulse through the channel, rinse and repeat

Re: TeraWave Satellite Communications Network

#89
post #58

Earlier quoted context omitted.

By my calculations there will be an average of 500 collisions, no? Each shoebox has an effective width of 2 feet, and with 50k of them that's about 1% density. With 50k in the other direction, and about a 1% collision rate, that's 500 collisions.

Seems like you're right, I didn't actually run through the statistics and just went with intuition. Yikes

Yeah my intuition was the same; if I had 1 second to make a guess I probably would have said 1% chance of >0 collisions

Re: TeraWave Satellite Communications Network

#90
post #11

From a technical standpoint: amazing achievement, and the tech nerd in me is in awe. But it feels like a lot of people don't understand (or care?) how much these companies are polluting the space. Before the "new wave", in 2010-2015 or so, Earth had around 1500 active satellites in orbit, and another 2,000-2,500 defunct ones. Starlink now has almost 9,500 satellites in orbit, has approvals for 12,000 and long-term pl…

"Polluting" is a very charged term. These satellites provide immense value. So far, there is no evidence these will stop us from watching the stars.

"value" is also a very charged term, and pollution is nearly purely a byproduct of the pursuit of value.
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