[...]So, for a 1600 sat, 32 plane initial constellation, you're looking at around 64 ASDS F9 launches, or 96 RTLS launches. Or maybe 32 FH launches at one per plane?Staggering numbers for a vehicle that has yet to hit 30 launches, and that's just the initial setup.
...those satellites launched in 2019...
Quote[...]So, for a 1600 sat, 32 plane initial constellation, you're looking at around 64 ASDS F9 launches, or 96 RTLS launches. Or maybe 32 FH launches at one per plane?Staggering numbers for a vehicle that has yet to hit 30 launches, and that's just the initial setup.If sats are built as inexpensively as rockets and they launch on reuseables, you can see why they're taking this approach and the end-user cost advantages they would/should have relative to most of other competitors.
Quote from: feynmanrules on 11/16/2016 11:00 pmQuote[...]So, for a 1600 sat, 32 plane initial constellation, you're looking at around 64 ASDS F9 launches, or 96 RTLS launches. Or maybe 32 FH launches at one per plane?Staggering numbers for a vehicle that has yet to hit 30 launches, and that's just the initial setup.If sats are built as inexpensively as rockets and they launch on reuseables, you can see why they're taking this approach and the end-user cost advantages they would/should have relative to most of other competitors.Also shows why they need to get launch rates up/turn-around times minimized.Initial 800 sats before service initiation... 32 launches (1 year?) probably one launch to each plane.Another 32 launches to complete initial deployment (end of year 2?).With only 5-7 year lifetime, need to have this pace if you want to get reasonable service from first 800 sats.Final deployment takes another 3-4 years, at which point you need to start replacing the initial 800...So, fully deployed by 2025, assuming start in 2019. 32 launches of 25 sats per year -- indefinitely.
And there's the dispenser mass to consider.
Quote from: GreenShrike on 11/16/2016 09:16 pmAnd there's the dispenser mass to consider.Surely they could try to design the satellites to not need a dispenser? Like the Boeing electric comm sat double stacks, or Orbcomm stacks, or the MMS sats on Atlas V? Might be a bit more tricky if you end up with more than one stack under your fairing though.
Also twitter from @malderi"Musk: Have to pay attention to security. Bad if hacked, either by AI or people." - very important IMO, this would get round state censorship, so attack by states possible."Musk: biggest concern about success: important to assume that competitors get better, too. Teledesic didn't." - it will be interesting to see how they build a system that can be expanded to more bandwidth and increased capabilities. This is one of the biggest system design problems IMO, get it wrong and the system is doomed in the long term."Musk: Hopeful that we can structure this to work with different countries. Don't want China shooting out our satellites." - setting up a global sales network will take time, need financing and other options that are sensitive to local circumstances."Musk: Plan on using Hall thrusters. Easy to make, no real production difficulty. Doesn't make sense to outsource."- good choice."Musk: Cheaper to have a bunch of PCs on racks than a few mainframes, this is the same idea."- distributed aspect more similar to PCs on desks"Musk: Don't see bandwidth as difficult issue. Space to ground has plenty of usable spectrum."- doesn't explain how he expects to get permission to use that spectrum"Musk: Going to cost a lot to build. Ten or fifteen billion dollars, or more. But revenues fund city on Mars."- SpaceX does not have the resources to fund this internally- Such a high investment, with significant chance of failure risks taking down SpaceX as well."Musk: Smaller satellites, few hundred kg, but capability of much larger satellites."- my guess is optimum size is somewhere in 300-600 kg range, driven mainly by antenna size."Musk: (timeline?) In the past, I've been optimistic on schedule. Recalibrating. Envision version 1 in about 5 years."- my translation - I'm aiming for 3 years, but I've been optimistic- planning on multiple versions from the start"Musk: Talking about around 4000 satellites. 4025 exactly in current design."- that is probably 100s of launches, maybe 50/year."Musk: Talking mostly around 1100km level. Space debris not much of a problem there."- with that number of satellites, they will have to take great care to dispose of them at end of life."Musk: 20-30ms latency everywhere on earth. Expand tech to Mars, not much fiber there yet."- a unique selling point, lower latency for long distances than earth bound networks"Musk: Developing world, but also options for people stuck with comcast."- big problem in developing world is that it needs to be very cheap both in cost of equipment and charges. Larger antennae on satellites mean smaller cheaper ground stations.- significant numbers in developed world have poor internet speeds and few prospects of significant improvement, not enough of a market on its own but still maybe $1B/year."Musk: More than half of global long haul comm over this system."- this is a biggie, global long haul market is massive. Competes directly with GEO telecom sats."Musk: Long term, rebuilding Internet in space. 10% of local business traffic."- another biggie, business traffic is concentrated in a far smaller number of customers than consumer, but generally needs higher quality of service and grade of service guarantees."Musk: Start by developing our own constellation. Comm, earth science, space science. Focus is global comm system."- looks like long term they plan for more than just this initial 4025 satellite global internet system.
Quote from: MikeAtkinson on 11/16/2016 04:44 pmThere are 52 satellites in a plane (2 spares), so just over 20 tonnes, which is about what F9 can place in that orbit, but possibly not a F9 with ASDS landing.Checking the NASA NLS II performance page, F9 FT + ASDS landing can put 11,805 kg into a 1150km 51.6 degree orbit. RTLS knocks that down to 8535 kg. That's different than the specified 53 degree inclination for the plane, so performance would likely be lower than that. And there's the dispenser mass to consider.At 386kg per sat, two ASDS launches of 26 sats would be 10036kg leaving 1769kg worth of performance for the dispenser mass and 51.6 -> 53 degree inclination change.Or maybe three RTLS launches of ~17 sats for 6562kg, leaving 1973kg worth of performance for the dispenser and inclination change.So, for a 1600 sat, 32 plane initial constellation, you're looking at around 64 ASDS F9 launches, or 96 RTLS launches. Or maybe 32 FH launches at one per plane?Staggering numbers for a vehicle that has yet to hit 30 launches, and that's just the initial setup.
There are 52 satellites in a plane (2 spares), so just over 20 tonnes, which is about what F9 can place in that orbit, but possibly not a F9 with ASDS landing.
The FH is going to be very busy, which is a good thing.
Most if not all the launches would be VAFB correct?
Quote from: wannamoonbase on 11/17/2016 12:36 pmMost if not all the launches would be VAFB correct?3200 out of 4425 birds are going to orbits they can hit with F9 RTLS from CCAFS or KSC (payload 8,535 kg to 51.6 deg 1150 circ LEO). Even with a dogleg to 53.0 or 53.8 degrees, that's likely more mass than they can fit in the fairing.
The current F9 fairing has a 4.6m internal diameter, that starts to taper off at 6.7m with a 70deg angle. If the satellites are 4m x 1.8m x 1.2m at launch, they are lucky if they can put four in a ring. At 4m long, they can't put two rings in the current fairing. Since the solar panels are 6m x 2m each, I would tend to think that the first dimensions are main body.
FREQUENCY BANDS REQUESTED FOR SPACEX SYSTEM10.7-12.7 GHz13.85-14.5 GHz17.8-18.6 GHz18.8-19.3 GHz27.5-29.1 GHz29.5-30.0 GHz
This is at 50Mhz per 1Gb spot/transponder [256QAM] * (2 transponders per frequency per spot [V/H]) / 2 (up down freq seperation) gives a possible 120 1Gb transponders per spot. If use frequency seperation between adjacent spots on same sat then it is 1/4 that at 30Gb per spot with a capability of:
Quote from: AncientU on 11/17/2016 12:48 amQuote from: feynmanrules on 11/16/2016 11:00 pmQuote[...]So, for a 1600 sat, 32 plane initial constellation, you're looking at around 64 ASDS F9 launches, or 96 RTLS launches. Or maybe 32 FH launches at one per plane?Staggering numbers for a vehicle that has yet to hit 30 launches, and that's just the initial setup.If sats are built as inexpensively as rockets and they launch on reuseables, you can see why they're taking this approach and the end-user cost advantages they would/should have relative to most of other competitors.Also shows why they need to get launch rates up/turn-around times minimized.Initial 800 sats before service initiation... 32 launches (1 year?) probably one launch to each plane.Another 32 launches to complete initial deployment (end of year 2?).With only 5-7 year lifetime, need to have this pace if you want to get reasonable service from first 800 sats.Final deployment takes another 3-4 years, at which point you need to start replacing the initial 800...So, fully deployed by 2025, assuming start in 2019. 32 launches of 25 sats per year -- indefinitely.Is it possible to do a rough profit model for this? With reasonable reusability we can estimate the launch costs for 32 launches per year. What is the potential revenue from such a fully installed satellite system? Does it dwarf the revenue from their existing business model?
Page 4 of the technical attachment has the breakdown of the intended use for each set of frequencies. Sat-to-sat is optical. SpaceX would need to get waivers to use some of their intended frequencies.
Quote from: oldAtlas_Eguy on 11/17/2016 03:20 pmThis is at 50Mhz per 1Gb spot/transponder [256QAM] * (2 transponders per frequency per spot [V/H]) / 2 (up down freq seperation) gives a possible 120 1Gb transponders per spot. If use frequency seperation between adjacent spots on same sat then it is 1/4 that at 30Gb per spot with a capability of:I am a layman here, but how can one fit 1Gb in a 50MHz bandwidth? I would think 50MHz allows for maximum of 50 Mb? Thanks.