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You’re not missing any spectral efficiency trick. Starlink maxes out at one customer per square mile or about one million total customers. It’s for areas beyond

You’re not missing any spectral efficiency trick. Starlink maxes out at one customer per square mile or about one million total customers. It’s for areas beyond cellular coverage. Cell networks could improve infill coverage consistency with professional installs of roof mounted CPE. That would help people who have a weak signal inside their home but good signal outside.

Retric 4y ago
Starlink is effectively a point to point connection with each satellite. There is no technical reason they can’t have 1 billion customers with a large enough network and the right hardware. The issue is economic. Target 1 customer per square mile and most of the orbit over land is useful, target 100,000 customers per square mile and most satellites are only beneficial over megacities like NYC. Due to the short lifespan of individual satellites they can adjust to market forces and new technology fairly rapidly. If for example China lets them in the economics around density change significantly.
- jcrawfordor 4y ago
  Directionality of antennas/electronically steered beams (off axis gain is not zero on the satellite or the terminal) and the relatively large bandwidth involved in these links imposes a limit that you'll hit even with an unlimited number of satellites. Calculating that limit is tricky but I don't think it's practical to cover urban areas for the reasons the parent brings up... cellular networks rely heavily on short effective range; the minimum achievable spot size for LEO satellites is still much larger than a typical urban LTE cell, and the terminal has the same problem of spot size in orbit being quite large.
  - rlt 4y ago
    The spot size is proportional to the phased array antenna size, right? Could SpaceX just keep scaling up their phased array antennas on the satellites as Starship reduces launch cost?
    - paranoidrobot 4y ago
      There's multiple physics problems involved. Spot size is one physics problem. Antenna size is a different one. They're orbiting low enough that atmospheric effects become a real issue. See the deployment in February[1] where they lost ~40 of the 49 satellites in a launch batch, because a Geomagnetic storm increased the atmospheric density at their initial parking orbit, overwhelming the ability for their control system to maintain orbit. So, yeah, they could then scale up the control system, too - but that makes them even heavier, increases fuel expenditure, reduces lifetime, etc. [1] https://www.space.com/spacex-starlink-satellites-lost-geomagnetic-storm https://www.space.com/spacex-starlink-satellites-lost-geomag...
      - londons_explore 4y ago
        The antenna array is parallel to the ground, so scaling it up has a minimal impact on drag. It increases mass, sure, but an increased mass to drag area ratio is usually considered a good thing (you'll be needing a better rocket to launch it tho).
        paranoidrobot 4y ago
        It's not always perfectly edge on, and it requires a control system to keep it oriented that way. This is why from the linked article: > The satellites were then placed in a protective "safe mode" and commanded to fly edge-on "like a sheet of paper" to minimize drag effects as the company worked with the U.S. Space Force and the company LeoLabs to track them with ground-based radar, it added.
        SEJeff 4y ago
        The v2 satellites they're testing out to launch on starship are in fact scaled up. The v1.5 they're launching now are larger than the originals which is why they've not launched 60 starlink satellites on a single falcon 9 launch in sometime.
      - gridspy 4y ago
        I thought they start at about 250 km after launch and then boost up to around 400 km. They don't have very powerful thrusters or gyros so they couldn't boost faster then they fell out of orbit. It seems that they are far safer once they have boosted up into operational orbit - that's why only the recently launched Starlinks fell back to earth.
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- Noumenon72 4y ago
  I don't follow your economic logic. Are you saying 100,000 customers need 100,000 different satellites which is too many to be used efficiently on the rest of their orbits?
  - Retric 4y ago
    That was in reference to the capacity to handle X customers per square mile not total. If you want to average 100,000 customers per square mile over a wide area you need a fuckton of satellites over that area. Basically a network that handles 1 customer per square mile might in theory have say 40 million customers worldwide eventually. A network capable of handling 10 people per square mile might cost 10x as much, but only increase that to say 120 million because some areas have less than 10 potential customers per square mile. Increasing that to say 100 or even 100,000 people per square mile would vastly increase the cost, but you hit heavy diminishing returns with a lower percentage of areas reaching those densities and many people with better internet options than starlink or simply can’t afford the service.
  - gridspy 4y ago
    The key thing to understand is that any specific satellite spends far more time over the ocean than over a dense city. So for each busy satellite you have 10 to 100 others on the same orbit which are still cruising over the ocean. To maximize efficiency you want to have similar load wherever the satellite is.
mlindner 4y ago
> You’re not missing any spectral efficiency trick. Starlink maxes out at one customer per square mile or about one million total customers. It’s for areas beyond cellular coverage. You're entirely wrong here. Their customer density is way higher than 1 per square mile... I'm not even sure where you get these ideas.
- reportingsjr 4y ago
  There are a bunch of estimates out there, but the best guess is that starlink can currently serve around 300 terminals per cell. Each cell is 146 miles, which is around 2 terminals per square mile. People may be clustered a bit, giving the illusion of starlink being able to support a higher density than this. Starlink isn't as scalable as people want to imagine due to the RF bandwidth SpaceX has as well as power requirements. This is part of why SpaceX made such a big deal over the 12GHz band that Dish wants to use. The next version of satellites may be able to support additional bands which will help, but starlink's still going to be fairly limited in terms of number of people it can support.

Retric 4y ago

Starlink is effectively a point to point connection with each satellite. There is no technical reason they can’t have 1 billion customers with a large enough network and the right hardware. The issue is economic. Target 1 customer per square mile and most of the orbit over land is useful, target 100,000 customers per square mile and most satellites are only beneficial over megacities like NYC. Due to the short lifespan of individual satellites they can adjust to market forces and new technology fairly rapidly. If for example China lets them in the economics around density change significantly.

jcrawfordor 4y ago
Directionality of antennas/electronically steered beams (off axis gain is not zero on the satellite or the terminal) and the relatively large bandwidth involved in these links imposes a limit that you'll hit even with an unlimited number of satellites. Calculating that limit is tricky but I don't think it's practical to cover urban areas for the reasons the parent brings up... cellular networks rely heavily on short effective range; the minimum achievable spot size for LEO satellites is still much larger than a typical urban LTE cell, and the terminal has the same problem of spot size in orbit being quite large.
- rlt 4y ago
  The spot size is proportional to the phased array antenna size, right? Could SpaceX just keep scaling up their phased array antennas on the satellites as Starship reduces launch cost?
  - paranoidrobot 4y ago
    There's multiple physics problems involved. Spot size is one physics problem. Antenna size is a different one. They're orbiting low enough that atmospheric effects become a real issue. See the deployment in February[1] where they lost ~40 of the 49 satellites in a launch batch, because a Geomagnetic storm increased the atmospheric density at their initial parking orbit, overwhelming the ability for their control system to maintain orbit. So, yeah, they could then scale up the control system, too - but that makes them even heavier, increases fuel expenditure, reduces lifetime, etc. [1] https://www.space.com/spacex-starlink-satellites-lost-geomagnetic-storm https://www.space.com/spacex-starlink-satellites-lost-geomag...
    - londons_explore 4y ago
      The antenna array is parallel to the ground, so scaling it up has a minimal impact on drag. It increases mass, sure, but an increased mass to drag area ratio is usually considered a good thing (you'll be needing a better rocket to launch it tho).
      - paranoidrobot 4y ago
        It's not always perfectly edge on, and it requires a control system to keep it oriented that way. This is why from the linked article: > The satellites were then placed in a protective "safe mode" and commanded to fly edge-on "like a sheet of paper" to minimize drag effects as the company worked with the U.S. Space Force and the company LeoLabs to track them with ground-based radar, it added.
      - SEJeff 4y ago
        The v2 satellites they're testing out to launch on starship are in fact scaled up. The v1.5 they're launching now are larger than the originals which is why they've not launched 60 starlink satellites on a single falcon 9 launch in sometime.
    - gridspy 4y ago
      I thought they start at about 250 km after launch and then boost up to around 400 km. They don't have very powerful thrusters or gyros so they couldn't boost faster then they fell out of orbit. It seems that they are far safer once they have boosted up into operational orbit - that's why only the recently launched Starlinks fell back to earth.
- deleted 4y ago
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- deleted 4y ago
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Noumenon72 4y ago
I don't follow your economic logic. Are you saying 100,000 customers need 100,000 different satellites which is too many to be used efficiently on the rest of their orbits?
- Retric 4y ago
  That was in reference to the capacity to handle X customers per square mile not total. If you want to average 100,000 customers per square mile over a wide area you need a fuckton of satellites over that area. Basically a network that handles 1 customer per square mile might in theory have say 40 million customers worldwide eventually. A network capable of handling 10 people per square mile might cost 10x as much, but only increase that to say 120 million because some areas have less than 10 potential customers per square mile. Increasing that to say 100 or even 100,000 people per square mile would vastly increase the cost, but you hit heavy diminishing returns with a lower percentage of areas reaching those densities and many people with better internet options than starlink or simply can’t afford the service.
- gridspy 4y ago
  The key thing to understand is that any specific satellite spends far more time over the ocean than over a dense city. So for each busy satellite you have 10 to 100 others on the same orbit which are still cruising over the ocean. To maximize efficiency you want to have similar load wherever the satellite is.

mlindner 4y ago

> You’re not missing any spectral efficiency trick. Starlink maxes out at one customer per square mile or about one million total customers. It’s for areas beyond cellular coverage. You're entirely wrong here. Their customer density is way higher than 1 per square mile... I'm not even sure where you get these ideas.

reportingsjr 4y ago
There are a bunch of estimates out there, but the best guess is that starlink can currently serve around 300 terminals per cell. Each cell is 146 miles, which is around 2 terminals per square mile. People may be clustered a bit, giving the illusion of starlink being able to support a higher density than this. Starlink isn't as scalable as people want to imagine due to the RF bandwidth SpaceX has as well as power requirements. This is part of why SpaceX made such a big deal over the 12GHz band that Dish wants to use. The next version of satellites may be able to support additional bands which will help, but starlink's still going to be fairly limited in terms of number of people it can support.