This space is going to become very interesting.
We know we're getting somewhere when Tristan da Cunha's gets a gigabit connection.
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This space is going to become very interesting.
We know we're getting somewhere when Tristan da Cunha's gets a gigabit connection.
I had not seen that number, 11,925, before. From that article, quote:
“In the coming years, the company hopes to launch 4,425 interlinked broadband-internet satellites into orbit some 700 to 800 miles above Earth, plus another 7,500 spacecraft into lower orbits”
I have seen the 4,425 number before. But I don’t know where the “another 7,500” came from.
SpaceX Vice President of Satellite Government Affairs Patricia Cooper's testimony to the Senate Committee on Commerce.
Link to article
FCC Filing with lots of info including low orbit constellation.
Yeah, in March last year 2017, they made another FCC submission where they proposed more satellites than their original submission. I believe the 7,500 are "Very Low Earth Orbit" (VLEO) satellites. The original 4,425 satellites fly at about 1,300 km, the VLEOs are at about 330 km.
Okay, thanks. Wow. That is a massive fleet. It’s going to take maybe a decade to get all of them in orbit?
I did read Technical Attachment
"Each satellite in the SpaceX System is designed for a useful lifetime of 5 to 7 years." So they need to get them to orbit in less than 5 years. LEO constellation has 83 orbital planes, so 83 launches is needed, more for 7518 VLEO satellites.VLEO is low enough to avoid Kessler syndrome. I don't know about LEO constellation. It is not so low.
I did read Technical Attachment
VLEO is low enough to avoid Kessler syndrome. I don't know about LEO constellation. It is not so low.
Initial deployment is 32 planes and 1600 satellites/ each plane gets 50 sats. If each is 500kg, and FH can put 63,000 kg into LEO, assuming sufficient fairing volume, and given the 6 hour 2nd stage rest capability, could SpaceX populate two orbital planes per FH launch, 16 total?
My first thought: No, it takes too much delta-v to change between LEO orbital planes. Fully reusable F9 would be good.
Before posting I thought again: Inclination is same, so perhaps delta-v is not too high. At least if you have time. LEO constellation has 5 different inclinations and VLEO only 3. It is very late. I should be sleeping...
So lets think about this. 7500 satellites, 5 to 7 year lifespan, lets say 6 years.
This means that SpaceX will need to launch one rocket with 105 satellites weighing about 40 tons every month for as long as they want to keep Starlink alive.
The cost of the 12 launches would be around 1 billion a year using suggested retail pricing. Of course SpaceX will do it at cost so lets say 500 million a year.
SpaceX would need to build 1260 satellites a year. Lets say the satellites are cheap and are 1 million a piece. That would be about 1.3 billion dollars a year.
So launches, plus satellites, plus operating and maintenance costs could be around 2.5 billion a year.
If they offer a $20 a month internet service world wide, then they would need around 11 million customers to break even. I think it is very doable.
This means that SpaceX will need to launch one rocket with 105 satellites weighing about 40 tons every month for as long as they want to keep Starlink alive.
The cost of the 12 launches would be around 1 billion a year using suggested retail pricing. Of course SpaceX will do it at cost so lets say 500 million a year.
SpaceX would need to build 1260 satellites a year. Lets say the satellites are cheap and are 1 million a piece. That would be about 1.3 billion dollars a year.
So launches, plus satellites, plus operating and maintenance costs could be around 2.5 billion a year.
If they offer a $20 a month internet service world wide, then they would need around 11 million customers to break even. I think it is very doable.
ccutrer
Active Member
Plus the actual bandwidth costs. I can’t imagine incumbent networks would be falling over themselves to give SpaceX good terms on peering arrangements.
After thinking this (and sleeping), I decided my first idea is correct. Change of orbital plane requires change in direction of velocity even if inclination is same. Doing that with v=sqrt(earthmass*G/(1150 km + earthradius)) = 7.281 km / s is difficult. This makes BFR less efficient in launching those.
Thus far we have not addressed the plan to cover the entire planet. Thus, by explicitly including polar regions and emphasizing remote area coverage as well, there is copious room for multiple business models. I suggest the probable Space X plans include the following:
1. Retail distribution wherever there is no regulatory prohibition;
2. Direct service to Tesla vehicles including all present capabilities plus many others;
3. Commercial fleet support serving:
3.1 TIR- (European cross-border customs-free trucking;
3.2 Logistics firms/customers- from FedEX, DHL, USPS, and nearly every global postal service and delivery company. Amazon too?!!;
3.3 Military/commercial tactical support services;
3.4 Shipping, the marine kind.
4. Wholesale distribution for large countries with unserved/underserved areas. This can include everywhere from Argentina to Zambia.
5. Weather observation, atmospheric monitoring and much more.
6. Just for being inclusive, this would easily supplant global remote Air Traffic Control (ATC). Current processes are exceedingly inefficient and expensive.
7. For good measure, it is not a stretch to see that GPS/Glonass are rendered irrelevant when this is in place.
8. What happens to Sirius/XM, Sky and all the others when Starlink happens?
It seems to me that the applications and general discussions vastly understate what this can and will do. Frankly, if all these are not among the opportunities why even do it?
I thought about these mostly because my curiosity was piqued by the afore-mentioned explicit polar coverage. Zero reason to do that unless the ATC, military, weather, etc applications were not planned.
Portions of all those topics are now covered by some constellation or another. The marvel of the SpaceX approach is that Starlink can do for satellite services what SpaceX has already done with satellite launches. It will be trivially easy to devote some of that bandwidth to thousands of subjects that now need dedicated satellites.
Realistically, Starlink threatens many, many special interests.
1. Retail distribution wherever there is no regulatory prohibition;
2. Direct service to Tesla vehicles including all present capabilities plus many others;
3. Commercial fleet support serving:
3.1 TIR- (European cross-border customs-free trucking;
3.2 Logistics firms/customers- from FedEX, DHL, USPS, and nearly every global postal service and delivery company. Amazon too?!!;
3.3 Military/commercial tactical support services;
3.4 Shipping, the marine kind.
4. Wholesale distribution for large countries with unserved/underserved areas. This can include everywhere from Argentina to Zambia.
5. Weather observation, atmospheric monitoring and much more.
6. Just for being inclusive, this would easily supplant global remote Air Traffic Control (ATC). Current processes are exceedingly inefficient and expensive.
7. For good measure, it is not a stretch to see that GPS/Glonass are rendered irrelevant when this is in place.
8. What happens to Sirius/XM, Sky and all the others when Starlink happens?
It seems to me that the applications and general discussions vastly understate what this can and will do. Frankly, if all these are not among the opportunities why even do it?
I thought about these mostly because my curiosity was piqued by the afore-mentioned explicit polar coverage. Zero reason to do that unless the ATC, military, weather, etc applications were not planned.
Portions of all those topics are now covered by some constellation or another. The marvel of the SpaceX approach is that Starlink can do for satellite services what SpaceX has already done with satellite launches. It will be trivially easy to devote some of that bandwidth to thousands of subjects that now need dedicated satellites.
Realistically, Starlink threatens many, many special interests.
Agreed. I think many people are unaware of what Elon is trying to do with Starlink, which is to build a global communications infrastructure that will offer high speed internet service everywhere and disrupt more businesses than most of us can imagine or have even heard of.
Running some quick calculations. It seems like FH could handle two planes in one launch.
Assumptions:
9.80665 m/s^2 for gravity
11.25 degree longitudinal shift (32 planes/ 360 degrees total)
340 Isp for Merlin Vac Engine
20,000 kg of satellites per plane (400kg * 50)
15,000 kg of extra fuel
4,000 kg for payload structure
3,900 kg for second stage premaneuver (empty weight may have fairing in quoted number)
42,900 kg total mass of second stage premaneuver
1,125 km altitude
7,281 km/s velocity (your post)
53 degree inclination
I get:
9 degree shift to change longitude
1,140 km/s Delta V required
12,422 kg fuel usage for burn
Margin: fuel burn is 2,600kg less than the extra loaded.
Extra fuel + 2 rings of sats + launcher, is 62,900 kg, which is under the 63,800 FH max LEO.
F9 @ 22,800kg LEO only has budget for 2,800kg for launcher + 20,000kg sat.
But I could have used a wrong number/ formula somewhere...
Can you calculate whether it might be cheaper to use multiple F9 rather than FH? I ahem zero technical ability to evaluate taht, but logically it seems they could do three F9
in less time, maybe more cheaply than to do one FH. Certainly it seems that such would be far easier, and could be done from more places. I apologize for my stupid question.
Not stupid at all.
Assuming full reuse on each:
Two F9 launches use
2 s1 fuel loads
2 s2 fuel loads
2 s1 refurb
2 fairings (lost?)
2 s2 lost
2 launch support
2 drone ship landings (due to pushing LEO limits)
A dual plane FH
3 s1 fuel loads
3 s1 refurb
1 s2 fuel load + 15,000 kg (1/6 full load)
1 s2 lost
1 fairing (lost?)
1 launch support
1 drone ship landing
I am 95% certain s1 fuel + s1 refurb is less cost than the extra launch support + s2 + drone ship landing needed for 2 F9 launches. Especially with mutiuse Block 5 cores. 99% certain FH is better if the fairings are lost (extra 6 million or so). FH also saves on pad usage/ range closures.
mspohr
Well-Known Member
Looks like they are projecting 40 million customers and $30 billion annual revenue by 2025.
I don't see large calculation errors (didn't check small ones
Are you planning 2. stage with larger propellant tanks? I don't think SpaceX will do it, because launch cost of BFR should be smaller than launch cost of F9.I think they should copy ion drive from Dawn Mission | Mission
Record-breaking use of solar-electric propulsion: 11km/s in space Δv.
Active powered flight 65% of the time, equivalent to 5.5 years of continuous thrust.
BFR would send larger patch of satellites. Satellites would change orbital planes with ion drives. I believe those satellites need lot of power for data link operation. That could be used by ion-drive.
