This thread estimates with downrange landing Block 5 can put 17.1t to LEO parking orbit. FCC filing shows each Starlink weights 386kg, so maximum # of satellites on this launch is 44.
Quote from: su27k on 03/07/2019 02:00 amThis thread estimates with downrange landing Block 5 can put 17.1t to LEO parking orbit. FCC filing shows each Starlink weights 386kg, so maximum # of satellites on this launch is 44.What is that 386 kg?- Dry mass?- Wet mass for 340 km orbit?- Wet mass for 550 km orbit, where the first batch of sats will go?- Wet mass for 1110-1325 km orbit?
Quote from: Ludus on 03/07/2019 08:56 pmIf each stack of 4 is about 2m high then the faring holds about 4 stacks, so 16 sats. About 7 tons of sats+dispenser. Seems like a reasonable payload for a first try.SpaceX built the dispenser I would say it could hold 5 sats per stack for an even 20 sats. But depending on hight clearances, Payload guide says 13.1m so it could go an extra stack for 25 sats.
If each stack of 4 is about 2m high then the faring holds about 4 stacks, so 16 sats. About 7 tons of sats+dispenser. Seems like a reasonable payload for a first try.
Quote from: Tomness on 03/07/2019 09:38 pmQuote from: Ludus on 03/07/2019 08:56 pmIf each stack of 4 is about 2m high then the faring holds about 4 stacks, so 16 sats. About 7 tons of sats+dispenser. Seems like a reasonable payload for a first try.SpaceX built the dispenser I would say it could hold 5 sats per stack for an even 20 sats. But depending on hight clearances, Payload guide says 13.1m so it could go an extra stack for 25 sats.According to 2019 SpaceX Falcon user guide on page 37.The main usable volume within the SpaceX payload fairing is a cylinder 4.6 meter in diameter and 6.7 meter high. Which I reckon that you can stacked 5 to 8 sats in 2 or 3 tiers.There is room for 2 or 3 more sats on top of the dispenser stack.So SpaceX can have between a low of 12 sats or a high of 27 sats inside the payload fairing. My guess is 15 sats in 3 tiers of 5 for the inaugural Starlink launch.
Quote from: Zed_Noir on 03/08/2019 06:08 amQuote from: Tomness on 03/07/2019 09:38 pmQuote from: Ludus on 03/07/2019 08:56 pmIf each stack of 4 is about 2m high then the faring holds about 4 stacks, so 16 sats. About 7 tons of sats+dispenser. Seems like a reasonable payload for a first try.SpaceX built the dispenser I would say it could hold 5 sats per stack for an even 20 sats. But depending on hight clearances, Payload guide says 13.1m so it could go an extra stack for 25 sats.According to 2019 SpaceX Falcon user guide on page 37.The main usable volume within the SpaceX payload fairing is a cylinder 4.6 meter in diameter and 6.7 meter high. Which I reckon that you can stacked 5 to 8 sats in 2 or 3 tiers.There is room for 2 or 3 more sats on top of the dispenser stack.So SpaceX can have between a low of 12 sats or a high of 27 sats inside the payload fairing. My guess is 15 sats in 3 tiers of 5 for the inaugural Starlink launch.22 satellites per launch would be a sweet spot because they are launching 66 satellites per orbit for the first constellation. More is better of course...
I don't think it is trivial to change planes. Also I don't know what the minimum number of satellites per plane is but the minimum number of satellites for operation is 812 IIRC.
Quote from: ThomasGadd on 03/08/2019 07:49 pmQuote from: Zed_Noir on 03/08/2019 06:08 amQuote from: Tomness on 03/07/2019 09:38 pmQuote from: Ludus on 03/07/2019 08:56 pmIf each stack of 4 is about 2m high then the faring holds about 4 stacks, so 16 sats. About 7 tons of sats+dispenser. Seems like a reasonable payload for a first try.SpaceX built the dispenser I would say it could hold 5 sats per stack for an even 20 sats. But depending on hight clearances, Payload guide says 13.1m so it could go an extra stack for 25 sats.According to 2019 SpaceX Falcon user guide on page 37.The main usable volume within the SpaceX payload fairing is a cylinder 4.6 meter in diameter and 6.7 meter high. Which I reckon that you can stacked 5 to 8 sats in 2 or 3 tiers.There is room for 2 or 3 more sats on top of the dispenser stack.So SpaceX can have between a low of 12 sats or a high of 27 sats inside the payload fairing. My guess is 15 sats in 3 tiers of 5 for the inaugural Starlink launch.22 satellites per launch would be a sweet spot because they are launching 66 satellites per orbit for the first constellation. More is better of course...Given that it's relatively easy to change planes, why would the number of satellites per launch be wedded to the number of eventual satellites per plane? (I'm making the assumption that it is easy to change planes, and I could be wrong about that)In addition, 66/plane is the eventual goal - but in order to first operate a "minimum viable product", what is the minimum number of sats/plane that will allow a full mesh? Whatever that minimum is, that seems like the number to aim for per launch, if the plane change is more difficult than I'm assuming. Then you would only need one launch per plane (assuming all planes are necessary for a minimum mesh) to start service. I imagine they could get away with both fewer populated planes (12 maybe?) and planes with lower populations, but I could be very wrong about this.
Someone calculated minimum number of satellites at 550 km and 35 degrees above the horizon... as I recall it was 11.
Quote from: ThomasGadd on 03/09/2019 09:39 pmSomeone calculated minimum number of satellites at 550 km and 35 degrees above the horizon... as I recall it was 11.11 per plane? 11 total planes? 11 total sounds implausible, but I'd love to see the math.
Quote from: WormPicker959 on 03/09/2019 09:54 pmQuote from: ThomasGadd on 03/09/2019 09:39 pmSomeone calculated minimum number of satellites at 550 km and 35 degrees above the horizon... as I recall it was 11.11 per plane? 11 total planes? 11 total sounds implausible, but I'd love to see the math.If all you care about is having a satellite visible at all times, you really don't need too many. Iridium manages to achieve complete global coverage with only 66 satellites. They're at 775km, so you'd need somewhat more at 550km but it could probably be done with around 100. The bandwidth you could deliver to end users would probably be pretty low though.
When do you guys think SpaceX will complete phase I of Starlink constellation? I am in the condrum of having horrible phone service for high speed internet, just little beyond rual fiber internet (I know!) & getting ViaSat or Hughes. I won't be able to game until Starlink or Rual Fiber. So I've been leanning to ViaSat with 2 year contract I am see if I can get to a 1 year with fiber or Starlink on the horizon
Quote from: Tomness on 03/08/2019 02:43 pmWhen do you guys think SpaceX will complete phase I of Starlink constellation? I am in the condrum of having horrible phone service for high speed internet, just little beyond rual fiber internet (I know!) & getting ViaSat or Hughes. I won't be able to game until Starlink or Rual Fiber. So I've been leanning to ViaSat with 2 year contract I am see if I can get to a 1 year with fiber or Starlink on the horizonI would bet you a beer that SpaceX won't be offering Starlink internet to consumers for the next two years, so don't let Starlink stop you. When your contract is up, Starlink may just be starting operations, optimistically.
Quote from: jketch on 03/09/2019 10:05 pmQuote from: WormPicker959 on 03/09/2019 09:54 pmQuote from: ThomasGadd on 03/09/2019 09:39 pmSomeone calculated minimum number of satellites at 550 km and 35 degrees above the horizon... as I recall it was 11.11 per plane? 11 total planes? 11 total sounds implausible, but I'd love to see the math.If all you care about is having a satellite visible at all times, you really don't need too many. Iridium manages to achieve complete global coverage with only 66 satellites. They're at 775km, so you'd need somewhat more at 550km but it could probably be done with around 100. The bandwidth you could deliver to end users would probably be pretty low though.Sorry I meant 11 per plane.
Quote from: ThomasGadd on 03/09/2019 10:08 pmQuote from: jketch on 03/09/2019 10:05 pmQuote from: WormPicker959 on 03/09/2019 09:54 pmQuote from: ThomasGadd on 03/09/2019 09:39 pmSomeone calculated minimum number of satellites at 550 km and 35 degrees above the horizon... as I recall it was 11.11 per plane? 11 total planes? 11 total sounds implausible, but I'd love to see the math.If all you care about is having a satellite visible at all times, you really don't need too many. Iridium manages to achieve complete global coverage with only 66 satellites. They're at 775km, so you'd need somewhat more at 550km but it could probably be done with around 100. The bandwidth you could deliver to end users would probably be pretty low though.Sorry I meant 11 per plane.Thanks for the clarification. Do you know how many planes are required, minimally? I know they're aiming for 24 in the end, but could they get away with halving that at first? 11/plane, 12 planes is 132 sats. This could be accomplished in less than ten flights, and would allow a minimum network to be achieved. This could be accomplished fairly quickly - if they can produce the sats fast enough, by the end of the year I would imagine. Would there be a benefit to build out a MVP with limited bandwidth like this? Start attracting customers, test along the way, setup ground stations/terminals? Once they start being able to demonstrate capability and take in revenue, it will go along way to shoring up investor support (if that's even necessary) and developing a customer base. On the other hand, launching a lackluster product might backfire or give it a reputation for sloth or low quality.