Every story about SpaceX satellite Internet (Starlink) is plagued by questions about high latency. I think Elon needs to plan on spending a lot of marketing money to overcome this specific misconception.
Starlink latency is quite good. LEO is a lot closer than GEO (less than ~1000 km* vs 35786 km.) SpaceX actually intends to compete with terrestrial systems on latency; many important routes will have significantly lower latency than any feasible terrestrial system.
Remember, fiber isn't latency free. It isn't even speed of light. It's about 70% SOL. Radio, on the other hand, is SOL (or so close it doesn't matter.) So there is a cross over point where the latency of a LEO satellite system is actually superior despite the uplink/downlink path.
*depending on which orbital "shell" is involved. figures range from 340 km to 1200 km.
No consumer will worry about latency or any other component of the physical feat of delivering internet via Starlink. Consumers are currently buying downstream bandwidth by the mbps from one or maybe two providers with no other options. Only technology oldheads who remember satphones and Hughesnet will worry, then research, then try it out for themselves. Starlink has the added benefit of being very easy to give a “consumer trial period.” It will sell itself, in the USA at least.
What do you mean remember HughesNet? People are still on it. Some of those people are young. All of them have been taught what latency is by having satellite internet.
There are plenty of non-technical consumers who have had a very unwilling education in what latency is and how it differs from speed.
EDIT: Sounds like this site's measurements for satellite internet are incorrect. Maybe HughesNet partners with fiber providers in some areas and therefore brings average speed down.
We could use objective reporting of internet speeds in finer detail. Any ideas?
Original comment:
--HughesNet's average latency is now 62ms, 58 ms jitter,--
Sure we do, we have the laws of physics. HughesNet has geostationary satellites. They orbit at ~22,200 miles up. Assuming speed of light, it's going to take ~120ms per hop. There's a minimum of 4 hops (you -> satellite -> ground station -> satellite -> you), or 480ms.
And that's assuming perfect conditions and ignoring the rest of the normal latency encountered online. It's physically impossible to have a latency lower than ~480ms with geostationary satellites.
t=0 You send out ICMP request
t=120ms it hits the satelite
t=240ms it arrives at the ground station, ICMP reply occurs
t=360ms hits satelite
t=480ms arrives back at the originating machine
The only way doing satelite-satelite at a GEO level would be useful would be
1) You're pinging a device on satellite in GEO (one you don't have LOS to)
2) You're pinging a device that's also connected via a different GEO 120 degrees away from the first
in this case you'll
t=0 You send out ICMP request
t=120ms it hits the satelite
t=240ms it arrives at the ground station 1
t=280ms arrives at ground station 2
t=400ms hits satelite #2
t=520ms arrives back at the destination
t=640ms response arrives at sat #2
t=800ms response arrives at ground station 2
t=840ms response arrives at GS#1
t=960ms response arrives at sat #1
t=1080ms response arrives back at originating machine
You could change that, but you won't save much in GEO as you're connecting to two different satelites, 120 degrees apart or 70,000km (235ms)
t=0 You send out ICMP request
t=120ms it hits the satelite
t=355ms hits satelite #2
t=475ms arrives at destination
t=595ms response arrives at sat #2
t=830ms response arrives at sat #1
t=950ms response arrives back at originating machine
Reality of course is that typical satelite latency is 800ms or more (depending how much you pay to skip buffering) rather than 480ms.
In GP's post the second satellite is the same satellite, just on the way back. The post assumes for demonstration that the ground station is the destination.
Color me skeptical that Starlink will reach its theoretical maximum capabilities, or that it is competitive with 5G. I'm fine with fiber until then. It's affordable in most of the world. The problem of broadband monopolies in the US is not going to be resolved by a new privately-owned technology. We should hold local politicians' feet to the fire, not throw money at new tech from a monorail salesman.
Regarding the 3rd world, Facebook offered India free internet with strings attached, and IIRC they rejected it. That idea wasn't too popular there or here.
Would Musk be given a pass for offering discounted or free internet to 3rd world countries, and what strings would investors suggest he attach?
> Would Musk be given a pass for offering discounted or free internet to 3rd world countries, and what strings would investors suggest he attach?
Why would he want to do that? Facebook wanted to do that, because that would drive more users to their platform. SpaceX wants to use Starlink in order to bankroll BFR[0], so what they want is to simply sell the service at a price point that generates them enough money. It's not beneficial to them to discount it, make it free, or play other shenanigans.
--
[0] - Or whatever it's called now; it'll always be the BFR in my heart.
If you have a lot of market power and you want to make as much money as possible the rational thing to do is to charge people according to their willingness to pay[1]. You can't do this perfectly but this is what is behind senior discounts and Intel's huge number of SKUs. Since people in Botswana can't profitably resell their internet in England, since Starlink can easily charge different amounts in different countries, and because the marginal cost of servicing a new region is approximately zero it would be crazy for Starlink not to do geographic pricing tiers.
If money is your only goal, that's completely rational. However, that's not how I've typically heard people champion Musk. He's been lauded as a progressive person whose aims are meant to serve humanity, not merely his wallet. Supposedly.
All human beings are complex and you can't just sort them into good people and bad people. Elon seems to be more idealist than most about the fate of humanity as a whole but also seems to be willing to work his employees to the bone, drive sharp bargains, etc to pursue that goal. He's said that he sees Starlink as a cash cow that'll fund future Mars colonies and I don't have any reason to believe that he isn't being sincere about that.
> All human beings are complex and you can't just sort them into good people and bad people.
Some would make the argument that if everyone worked with only their wallet in mind, we'd be better off. I wouldn't.
> Elon seems to be more idealist than most
Elon is not an idealistic engineer, he is a businessman. He actively misleads about products he must have been told will not meet the timelines he promotes.
> about the fate of humanity
Not sure where you get this idea. The way he talks about AGI taking over the world is creepy. He thinks it's inevitable, nevermind that we have no idea how to design anything close to AGI.
It's not like serving humanity and making money is mutally exclusive. If there are markets in developing countries he can serve cheaper than anyone else both sides profit: he makes money, the people get cheaper internet.
That said, internet already tends to be the infrastructure demand best satisfied in developing countries. Building cell phone towers is much easier than building roads, and with cheap labor and no purchasing power comes cheap internet.
> If there are markets in developing countries he can serve cheaper than anyone else both sides profit: he makes money, the people get cheaper internet.
Let's see whether it is net-neutral internet or not, then judge. My guess is it will have exclusive offers to content distributors in order to lower cost.
I think your parent also meant the developed world.
In devloping countries it's sometimes much easier to get fibre. No or very little infrastructure means no old copper wires lying around. You can go fibre instantly this way.
Fiber is affordable in cities (a market nearly impossible to service by satellite anyways). Even developed countries struggle with deploying fiber in rural environments.
Every satellite internet offering targets rural settings, ships and planes. StarLink is no different, just that they will be competitive in a wider range of such settings.
>> We should hold local politicians' feet to the fire, not throw money at new tech from a monorail salesman.
We need to do both, as Seattle has proven with its sporadic availability of gigabit fiber and the shutdown of third parties attempting to bring it here.
Yeah, I happen to live in an area that CL offers 6mbps maximum to, and it is weirdly in a minority-dense part of Seattle metropolitan. They have zero plans to expand to our area, they've stated repeatedly.
The city contract requires they service the lowest income parts of the city first, hence the extremely patchwork rollout over the last few years.
Due to the mandatory client base skew, the city is causing them to redline middle and high income areas of the city. Fiber is in Georgetown and Rainer Valley, but your SoL in Fremont's built up areas and in Sand Point.
Universal coverage should have been mandated, but its easy to end up like Kenmore (which required total Fios coverage from Verizon, now Frontier) and has seen Finn Hill go unserviced for years. Enforcement of the franchise contract is just as critical as initial negotiation.
Outside of a few select areas, most of Seattle only ever saw ADSL (or no DSL in parts of the north end) as we didn't allow large VDSL2 cabinets in the public ROW. I think this has caused Centurylink to build fiber in the city, as they've rarely overbuilt VDSL2 areas like Bellevue, Kent & Auburn.
I've noticed they seem to offer ADSL (6mbps) after 6pm or so at addresses that already have fiber, presumably their prequal database for fiber goes offline for a few hours a day.
I've called multiple times and schedule a check every three months to see if it's been updated. Been doing that for years. Won't give you my cross streets but I assure you, they have nothing for me.
They say it's available just a few blocks over. That's been the case for a long time and they can't seem to get it about 0.25 miles further. Been that way for years.
Starlink (and other similar systems that are hopeful to launch) are the real competitive threat that Google Fiber only partially lived up to being.
It threatens the existing entrenched providers everywhere. They can't hide from it. They will have no choice but to respond. They face a scenario losing tens of millions of access customers over time to this approach. And the existing options are priced so high in the US, it provides a big fat margin opportunity for Starlink & Co. to target (and ride for the benefit of paying for the buildout).
We had to go to space to route around the cable oligopoly, beyond their local crony jurisdictions.
Nope, Starlink would be crushed by tens of millions of customers (mostly concentrated in major metro areas) in the US and those customers would switch right back to cable. The capacity isn't there.
Can you show me the definitive proof that Starlink (along with its competitors, who will plausibly also launch a vast number of satellites) can't support eg 20 million customers in the US over time? I'd be very interested in that demonstration of the limits on the market.
Also can you support the premise that their customers would be concentrated in major metros, when the biggest beneficiaries will be outside of metros where broadband options are drastically worse (which is why the primary market for HughesNet the past two decades has not been concentrated in major metros).
Access providers in metros can soundly compete with Starlink. They'll lower prices, increase speeds, improve bundles, etc. Their infrastructure and customers are already in place there, they won't just ignore Starlink, they'll compete. That heavily limits the upside potential for the Starlink concept in metros. It's everwhere else, mostly lacking any real broadband, that Starlink & Co will face minimal competition and will particularly lure customers. It's why HughesNet still has over a million customers today.
I've seen a lot of people claim - with very little supporting evidence thus far - that the market is extremely limited due to capacity restraint.
While you're proving out your claim, if you don't mind given that you've got a strong handle on the market ceiling, please provide what you believe to be the maximum subscriber potential for Starlink - and the approach in general - in the US over time.
I think Starlink is for rural customers and can't compete with decent wired broadband. You were the one who seems to be putting it against cable (which exists in the metros, not in rural areas).
The MIT work linked in this thread calculates a total worldwide capacity in the ~20 Tbps range for Starlink.
I didn't see the link, but here's the presentation[0] I believe you're referring to. It estimates Starlink's max total system forward capacity at 23.7 Tbps.
> All of them have been taught what latency is by having satellite internet.
Yes, life is a great teacher.
HughesNet sends me a post card every quarter or so. Sure I live in the middle of nowhere and would seeming be likely to want it. What makes me laugh is even the old people in the area who you'd think wouldn't know how to use a computer will warn friends, neighbors and community not to use them. They may not know the term latency, but they know that the quality of calls are poor and they know uploading videos from their phones takes way too long.
I was going to ask, "Didn't HughesNet try this?" .. I didn't realize they were still around, although it does make sense for a lot of rural areas with limited broadband options.
Or RVs. Even chain stores use the service: easier to manage 1 big Hughes subscription instead of 500 or 5000 different local ISP contracts, each with their own quirks.
LTE hasn’t made as much of a replacement in Home Broadband in rural as much as you’d think largely due to tower congestion. Cell site density is so low — plus deprioritization at 30/50gb.
In addition you’ve usually got only 1-2 networks in deep rural.
competitive gamers make up a very small percentage of all internet users (or even gamers!). Like professional athletes, they will move or go to a special facility for this sort of latency requirement.
Many games are not as latency sensitive as you think - people used to play over modems!
If by "competitive" you mean anyone who plays any sort of real-time game such as RTS, FPS, or even real-time mobile game. Many consumers may take a while to figure out that latency is the reason they lose/die when it doesn't look like they should, but they will feel the effects immediately.
Granted users in rural areas are likely the most apt to benefit from this service and those users don't likely fantastic internet to begin with. However, if SpaceX markets this to areas with decent quality internet they're likely to get a bad reputation for "crappy" internet.
Yes, even those people make up a tiny fraction of the internet. Satellite internet typically will not work for those people, and there is no point in trying to sell to them.
That's the same percentage as Linux users, and just yesterday I closed my Box.com membership because the don't have a Linux client "due to low demand".
Ehhh, not sure about this. If you're a parent and your kid is begging you to get faster internet, you might listen to them a little bit. If their marketing can get those kids to do that, then that might be a successful campaign.
I agree in principle that kids can influence parental purchasing, and that marketing is geared to take advantage of that. But the effect appears to be most effective for items that are exciting and tangible objects in front of the child; think checkout aisle candy, not “boring” adult things like finance and bills.
Here’s an interesting parallel; how much say does any child have in the cell phone plan that a family uses? Probably damn close to 0. That’s a decision that the parents make on their own, and dictate the rules of usage to their children. I suspect that internet service will remain that way as well.
For candy and toys, sure. But there are a wide range of goods and services where the child has 0 say. Cars, homes, and even cell phone companies never market to kids in order to influence the parents, implying that children have no meaningful impact in these areas.
Now these services advertise to adults with children, such as being able to call your kids whenever with the unlimited cell phone plan, but that’s still advertising to the adult, not the child.
I play League of Legends and have only DSL but my ping is only 35 ms and I can't complain -- many other players have it worse than me.
What did make it impossible for me to get kills was having 30 ms of latency in my display system. I think the network latency is well-compensated (if the typical user has 50 ms of latency, just delay me by 20 ms) but the display latency kills me. When I switched to a different monitor I started playing much better in about five games.
I think the game generates a 10 MB log for a 30 minute session so the bandwidth requirement is not much.
I had the same experience playing Titanfall earlier; in that case turning on the "Game Mode" on the TV turned me from someone who couldn't win at all to somebody who could get halfway up the ladder.
Display (and input!) latency are real things, and matter quite a bit. There have been studies in the past where people measured the full button press to frame update time using high speed cameras, and not all games are equal. As for game mode on TV's, that specifically why it exists. As a passive medium a little latency doesn't matter, but when a system is responding to input, latency is noticeable.
If you're interested in how different TV's perform, segregated by their individual input ports (in cases where some ports are optimized) and modes, check out https://www.rtings.com/. I used it a couple years ago to pick out a good 4k TV as a monitor, and the very thorough information helped me pick out something that works well as a computer monitor (and also for the occasional gaming).
How does 30ms of display latency affect LoL gameplay? I don't play it, but I've seen videos of it a few times and with it not being a FPS I wonder what aspects of the game are that greatly affected with an additional 30ms of display latency.
Mind you, any mouse lag drives me up the wall. I've never measured at what point I perceive that mouse lag, but it's a fairly low number I'm sure.
I guess it depends on the game being played. When I played C&C in the 90s over modem, the latency was huge but it wasn't a major concern for that type of game.
Now that I play real time sports, and I'm no professional, it still makes a big difference in my enjoyment of the game when I'm playing at home with ethernet and top tier internet service vs playing at my parent's house on wifi and basic internet. The lag can really affect my ability to play my best and it sucks losing because you don't have a low latency connection.
That said, I'm very curious to see what the latency will be, because if it's within a reasonable range it could be acceptable. Either way, I don't think even casual gamers will have a significant impact on their sales, but it will have some if the lag is too great for some of today's games.
Try having an RDP session to fix Windows servers based in Australia with 400+ ms latency (Europe is unfortunately nowhere near Australia) on your GUI, the ordeal will leave a permanent scar on your psyche.
The speed of light is insignificant for such a short distance. Even if the signal travels as much as the circumference (40000km) of the earth at 70% lightspeed it shouldn't take more than 180ms. The lowest possible latency between Australia and Europe would be 60ms. Congested networks and network routers with suboptimal routes introduce far more latency than the distance. I regularly get between 100ms - 200ms latency between California and Germany and the latter number includes the realtime encoding/decoding of the video stream.
Internet gamers are fine with double-digit millisecond latencies, and this is what Starlink will offer. It takes less than 4ms to reach 1000km LEO orbit, so 16ms for the full round-trip (you -> sat, sat -> server, server -> sat, sat -> you). Make it 2ms ground-to-satellite and 8ms round-trip if you believe the model from this thread[0] (satellites at ~600km). Using its numbers, add 2x 2ms for each inter-satellite link you have to travel back and forth.
It still adds up to sub-100ms latencies. It ain't bad.
With the right type of architecture, low-earth satellite could offer better latency than terrestrial.
terrestrial internet goes through optic fiber in which the speed of light is maybe half the speed of light in a vacuum. Already HFTs use microwave links to shave off a few milliseconds between New York and Chicago. From Boston to Seattle the extra 600 miles up and down from the constellation would be overcome by the fast path along that route.
Note that requires switching from one satellite to the next, not the "bent pipe" architecture to your local rent seeking wireless company that StarLink and other LEO constellations plan.
I’ve read the paper that started this idea of Starlink being a low latency alternative for hft (http://nrg.cs.ucl.ac.uk/mjh/starlink-draft.pdf) There are a couple of problems with the paper. The first is that they establish a range of acceptable latency as existing between the great circle route and the fastest ping time on the internet between two points. For example they found that NY to London was 75ms round trip on the internet. However the long time standard bearer for a pure fiber path had been 64ms until the latest gen cables arrived in 2016. At that point the latency was sub 60 ... very comparable to the 55ms great circle route. But it’s important to understand that the starlink point to point route will be constantly changing — so only in one or two instances will that latency even come close to the existing terrestrial routes. More often than not the latency would trend closer to the 70ms range - well beyond anything considered competitive either in the current generation of routes much less the prior generation. It’s as if the authors simply had no idea about the hft market and what latencies might be needed (all of which has been published publicly). But there’s another problem with the study. For the solution to work, spacex would need to dedicate one of its laser links to enable communications across other satellites and dedicate that capacity to this application. And further, the study did not address the issue of optronic delays within the satellites. Most microwave manufacturers care little about hft latency tolerances and intermachine delays can be 1-2ms per hop. Assuming starlink to not to be much different (although I don’t know this to be true or not) that would definitely add even more latency to the equation. So all in all while it’s interesting and will do amazing things for consumers and enterprises, I don’t see starlink being a competitive hft solution unless the route in questions is really long and a lot of other engineering stuff can be made to work to enable it. Call me a skeptic but I don’t think we will see it.
I’m just pointing out that the slice of consumers who are a) internet gamers b) concerned about Starlink latency and c) still think Starlink is old school geosynchronous satellite. Gamers will of course worry about latency just like they optimize every other aspect of their setup, but not to the effect that SpaceX needs to mount a marketing campaign to that effect.
Yeah, and they'll care enough to actually find out what the latency is rather than reflexively shooting things down. And don't forget word of mouth. All it takes is one prominent streamer that you follow, or anyone in your friend group, saying good things about it -- and now it's on the table for you.
I don't think you're allowing for the the temerity of terrestrial services. They will conflate the poor performance of legacy satellite systems with this system. They will exaggerate the latency deficit over short paths and allow people to think this is the general case. They will do this to leverage the preexisting perception of poor satellite service performance that so obviously prevails.
Only a solid marketing campaign can deal with this problem.
Another thing is jitter. By design flying satellites are going to create jitter, and even with good latency, it can be bad for stable video streaming, video calls, etc.
That's true and bandwidth is actually something I've been wondering about: what kind of bandwidth can an inexpensive ground-based system get, reliably? Sending bits in a fiber is famously free of interference, while hundreds of miles of atmosphere is notoriously bad as a transmission medium. I haven't seen any kind of calculations around this. How many clients can hook up to one satellite concurrently, what kind of bandwidth will each get, realistically (theoretical max bandwidth is not so interesting). Without more information, my first thought has been that Star link sounds like an excellent, satellite-based internet technology ideal for connectivity in isolated places (far from urban areas, on ships and airplanes, etc) but which may not really be competitive for consumer internet access in urban areas. Hope I'm wrong.
> what kind of bandwidth can an inexpensive ground-based system get, reliably?
Theoretically 56 Kbit, but practically closer to 40 Kbit. I'm being serious! Given the choice between hugely expensive and high latency satellite Internet and dial-up, many have opted for dial-up, even in this day and age! We're not even talking that far away from urban centers, either, especially in hilly areas. A couple hour's drive outside of San Francisco is enough to get to cell-phone network dead spots, never mind LTE. There are some hyper-regional wireless ISPs using 802.12-based gear (Uniquity), but those are the exception.
Given that, (which is so extreme that I'm sure that not everybody that reads this will even believe me), any competition to HughesNet will be very welcome. Prior to SpaceX, the cost of getting a constellation of satellites into orbit was prohibitively expensive, but with this being done by SpaceX, the launches for this will be done "at cost", (corporate accounting and cost centers notwithstanding). (Which, mind you, is still several million dollars per launch in rocket fuel.)
Hopefully that means a genuine competitor to HughesNet, but that's a low bar. There is a large initial investment (of time and money), but FCC approval is an important first step towards providing this service.
The atmosphere shouldn’t be too much of a problem. It thins out very rapidly over a few km altitude, and the beam is going almost straight up. It’s nowhere near as bad as the same distance through the atmosphere at near ground level.
I am excited about the possibility and think it will (eventually) sell itself though word of mouth (how exactly do you advertise better Internet access to a market with poor Internet access? Billboards and USPS mailers?). I doubt most consumers have the background to know difference between latency and bandwidth, so hopefully this is price competitive with HughesNet!
I think that the key competitive advantage is exactly how cheap it is to acquire new users. Anyone that is off the main grid can still get decent internet without signing up to a long term landline contract. This removes one of the big barriers to entry and changes the industry as a whole.
At some point Verizon and AT&T will get the service requirements relaxed so that 5g counts as servicing a home. At that point they’ll run through and service all of the old rural installations. Hopefully the rural power companies do the same with the fiber they run inside their steel lines. There’s my guess anyway.
There is a reason for this as there are a lot of customers in on place. Satellite based internet allows you to have your infrastructure where you need it, even this requires a close control of your orbits. And then question is whether satellite internet will be a) faster b) be more reliable and c) cheaper than ground based fibre and 5G. If yes it might give these two alternatives a hard time even in metropolitan areas. If not satellite based internet will only be interesting for rural areas. Not sure if the potential higher prices off-set the smaller customer base. And in developing countries higher prices are basically off the table anyway.
Satellites still are in space, so everything is more expensive up there, getting things up, repairing things, building things for space, operating things in space...
I would say there are a lot of people who live in cities/towns instead. You need the scale for things to work. I hightly doubt this project is only aiming at people not living in cities.
VOIP. 150 ms max recommended, noticeable degradation of UX at 250ms. Many phone operators use wifi to connect when they can. If people's phone does not work well, they'll complain.
Sorry for this shallow comment but I've read the title several times now, my mind races to the same thought:
>...to sell wireless high-speed internet from space!
"I wish them wild success, it's promising to see the opportunity for disruption of our telcom mafia as wireless comms tech evolves, but selling internet from space... total horseshit! Success or not, most space internet subscriptions will be sold from a call center in India." /s
Please consider my apologies. I was taken aback by you're reply. It was not my intention to express bigotry but I thoughtlessly offered an unintelligible attempt at poor pedantic humor absent of context and comedy. You replied quickly and so I choose not to delete it.
I enjoy watching this technology as it moves to become an available option. The article is 9 sentences of an information scarce announcement, but as is often the case, I returned here to find plenty of useful information in these comments. Interestingly, ATSC 3.0 which is packet based and already overflowing with DRM now looks to be nearing a consensus. As early as 2020 (US) it could prove to satisfy enough content distribution traffic to reduce some downstream bandwidth demand and relieve congestion. SpaceX in partnership with ATT or CenturyLink for dedicated up-link over DSL would be an interesting offering.
https://www.atsc.org/wp-content/uploads/2018/01/A360-2018-Se...
As someone who has run a tiny ISP in a tiny town, I assure you “people” are much more knowledgeable than you assume. I was actually able to disable all monitoring systems, since I would get a phone call, immediately following any event that caused high latency, or any kind of internet disturbance. I learned that people who live in smaller rural towns are in some way much more dependent on the internet to provide things like entertainment, news, info, media, since there are fewer social events, theaters (etc, etc).
Is it 15ms to the satellite? If so, that's like 30ms to land, which would negatively impact gaming if it still needs to travel from where it lands to the end goal (via normal pathing?)
1000 km / speed of light = 3.34 ms. Suppose you want to ping a server next door to you and your ISP is a satellite 1000 km away. The distance your signal travels is 1000km from client to satellite, 1000 km from satellite to server, 1000km from server to satellite and 1000km satellite back to client. 4000 km at the speed of light is 13.34ms (the transceiving latency is probably negligible in comparison, though I'm not 100% sure about the DSP requirements for this sort of system)
If the target server is far away and the signal goes 7000 km from satellite to satellite in space before coming back down, then your signal it will need at least 46.7ms more in space for a 14km round trip in space, which results in a minimum possible ping of 60ms to ping a server 7000 km away. Fiber-optics are 30% slower than radio links, so this 60ms minimum is 10% lower latency than the best fiber-optics can do: (7000 km / .7 speed-of-light) = 66ms
If the distance to your server is 2.333x the distance to your satellite you will have lower latency with radio than fiber optics. Bringing the altitude of the satellites down will make a big difference, but you also need a lot more of them in a constellation to have low average distances.
But for something more realistic for gaming, a player in Boston hitting a server in NY. The fiber message travels something like 200 miles, while the satellite message travels 2,200 miles.
Radio waves are faster than light going through a fiber optic cable, and the satellite mesh network will have fewer hops (switching packets on fiber is expensive time-wise).
The difference in latency won't be nearly as bad as a naive comparison of these two numbers would suggest. Depending on what hops your terrestrial traffic is going through, the satellite transmission could well be faster. To give you a trivial example, I'm seeing 11 ms ping right now to a server within my own city, that's only a couple miles away. This is ~0% signal transmission delay and ~100% switching delay.
It's still transmission delay, you are underestimating how fast routers forward packets today.
Likely the server has a different provider and them and your ISP does not peer in your city, so you have to go somewhere else where they peer (or where their transit peers).
All the uplinks of my ISP with one exception (carrying traffic through various lines up to european IXs) are connected to the Internet through the same MSK-IX which is 900 miles away from my city and adds 4ms latency. I don't think GGP's traffic route is that long though.
Not sure what you are talking about. 900 miles is ~1500km, 1500km at the speed of light in fiber (2/3 of SOL) takes 7,5 milliseconds, so 15ms roundtrip.
But I don't see why it's relevant. Forwarding in modern ISP routers is on the tens to hundreds of microseconds level, even if there are many hops it does not add up to that much. So what he has is likely not "switching delay", and even saying that 11ms is 100% switching delay when it's the same city (low amount of hops even if multiple ISP's are involved) is just ridiculous.
Took that number (it was for one way trip though) from memory, might be scrambled. Just checked, RTT 17ms with 3ms jitter for me.
22ms RTT is still too much though. Even with centralized network for cross-border traffic like in my country, there are IXs way closer than those 1500km to any town on european part and obviously to the East of Urals (the longest distance between IXPs is ~3000km for Krasnoyarsk-Khabarovsk, the longest distance to the closest IXP of 1500km have Norilsk - the most northern city on the globe and it's satellite Dudinka).
Boston to New York is 215mi or a 430 mile round trip. At 200 miles up where they intend to put the satellites orbiting over major cities, it's going to be about 1000 mile round trip.
I thought that the US servers for most games are in the middle of the country to get the best average ping for a cross-country audience. Blizzard is like Chicago and Texas.
> Boston to New York is 215mi or a 430 mile round trip.
Assuming terrestrial lines travel as the crow flies, which is not all that likely (but probably not too far off).
> At 200 miles up where they intend to put the satellites orbiting over major cities, it's going to be about 1000 mile round trip.
Other people here are noting that fiber signals travel at ~70% the speed of light, while radio waves travel at very close to the speed of light. If that's true, it puts the optimal time for land based optical communication at ~3.3ms[1] ms, while the optimal time for a low orbit satellite at ~5.4ms[2] (if I didn't screw up the math). That's slower, but not by a whole lot, so it might even be better than you're predicting.
Also, are people actually getting sub 4ms round trip times between Boston and New York? If not, then the difference here might be entirely subsumed by other factors.
Nope, the biggest AWS region is in Virginia (as well as a bunch of others, energy is cheap there). There are also lots of datacenters in Dallas, TX and San Jose, CA. NYC has a lot of connectivity (throughout the northeast, and transatlantic) but the cost of real estate is so high that it is uneconomical to operate lots of large datacenters there.
The majority of the population in the US is in the eastern half (1/3 in states on the East coast), so you don't actually decrease median latency by putting datacenters in the geographic center: https://commons.wikimedia.org/wiki/File:United_States_popula...
That doesn't disagree with what I said. The majority is still in the East (the mean is East of the geographic center), and you don't want to optimize for average latency anyway. You'll get the best median latency with two datacenters by putting one on the mid-Atlantic coast (~180M people East of the Mississippi) and one on the mid-Pacific coast (another 50M in Pacific Coast states). That means the latency for ~2/3 of the population is way lower, and the max latency is still about the same as putting them in the center of the country.
Not usually. In my experience, they usually follow the typical popular datacenter areas e.g. East Coast/West Coast. I've mostly only seen really popular games offer Central locations like Dallas/Chicago. But it's getting a lot better now that vultr (COD uses them) and other VPS providers get more and more locations.
The 30ms figure is just the earth->satellite->earth part though. It still has to go through terrestrial wires to the server, and then be processed, and back through wires to the transmitter.
30ms would be you and the game server both on Starlink, on the same satellite. Otherwise, you have to add that to the latency between the ground station and the target server.
IIRC, the plan with Starlink is to have many stations that are supposedly easy to operate in many large-ish datacenters in major areas as opposed to systems like Iridium which have few, complex downlink stations in comparison.
Maybe from me to a geographic location 400 miles away, yes. But what about 4k miles away, like coast to coast?
That would probably depend on how many satellites it has to bounce through and how far it has to travel terrestrial, but I would think there is a geographic distance where that 30ms is faster.
The high latency questions are only from people who really don't understand the industry. The question most analysts in the industry ask are about how they plan to be profitable.
I disagree. I think people equate bandwidth with speed, because that's what all of the commercials and marketing materials say. Latency is hardly ever mentioned.
Yes people have been burned by HughesNet and garbage like that. But it won’t take much to educate them, people can understand the difference. A simple graph showing the ping times and people will get it.
I suppose this argument works really well on HN. how many people do you think know or care about a ping time? if they did, don't you think we would see all of the commercials for broadband bragging about their latency instead of bandwidth? Streaming media dominates the internet today, and that's unaffected by high latency.
ATSC 3.0 is a possible avenue for offloading some streaming traffic. It seems that the consumer hostile packages we've come to love are taking shape and 2020 may see some adoption...
They probably won't... Links between satellites will use a different routing scheme. Traditional network protocols will "disappear" at the sending ground station, only to "reappear" on the receiving one.
A video link of a simulation was posted on a different comment that shows the "routing" between multiple satellites.
Why wouldn’t they use something like BGP to route between the satellites? Because the topology is explicitly known ahead of time and so the routing can be more “hard coded?”
An interesting side effect of this network is that latency experienced by any two users, anywhere on the network, should be close to equal.
It depends. If you're connecting to a data center across the street, the latency will probably be worse. If you're connecting to one on the other side of the world (or somewhere where the packets have to take a more circuitous route), the latency might be better. The satellites aren't that high up so latency won't be a huge issue.
I think bandwidth limitations will be more problematic. The Earth is really big, and there's not really a good way with LEO orbits to focus your satellites over urban vs rural areas. IOW you can focus coverage on lower latitudes but not really certain longitudes.
IIRC previous FCC filings said each satellite would have ~20 Gbps of bandwidth. That'll be great if you're in a rural area, and I think the gigabit speeds some people are hoping for are actually possible in certain situations. However a lot of people think that they're going to be able to replace the Wifi router in their apartment with a Starlink antenna... I don't think that will be practical any time soon. I'm not an RF person but I doubt there's enough spectrum for each satellite to have tens of thousands of users simultaneously.
edit: also, like with 5G the signal quality is going to be crappier when it is rainy or cloudy.
It's going to be a similar situation to cell phones. When you purchase the product, you know that it will be slow some times outside of your control, but that's the trade off for being able to get connectivity almost anywhere. With no hassle as long as you can see the sky. On your boat? Sure! On your farm 30 miles from anything? Sure!
It will be interesting to see if they geo-lock the base stations or will allow you to move them and then re-calibrate/re-register your location for load balancing.
SpaceX actually intends to compete with terrestrial systems on latency; many routes will have significantly lower latency than any feasible terrestrial system.
I would like to see a framework, where the backend of a cloud system can migrate opposite to the direction of orbit, so the same virtual cloud server could remain (by 'hops' where it serializes a copy of itself, then fails over to the copy) more or less geostationary. Such migrations would happen as seldom as once per 10 minutes.
My game server cluster isn't too far away from having such a capability. (I was planning a variety of capabilities, such as using cheap GCP "ephemeral" instances by quickly failing over to such copies.)
Why would you need to do this? The constellation still needs downlinks - and the downlink nearest the physical location of the user should always be where that traffic pops back onto the Internet.
For a game server cluster, I would be running a game loop implemented as a series of pure function functor-like objects, located "very near" a spatial database. In that case, I would be migrating to provide the very lowest latency, as if the system were running on a "geostationary" server just a few hundred miles overhead. (Which has to pause for a quarter second, once every several minutes.)
That sounds like a terrible experience. You want to avoid latency spikes at all costs. People might not like latencies as high as 100ms to 200ms but it definitively is possible to enjoy a laggy game like that. Suddenly getting a 500ms latency every minute will cause a lot of weird and unfair situations that can basically ruin the entire game.
The usual latency should be on the order of 30-40ms round trip.
Suddenly getting a 500ms latency every minute
No one said anything about that. The client should have some form of dead reckoning, and there should be an edge server that maintains connections. With the right kind of game mechanics, no one notices the server disappearing then reappearing behind the scenes. I cite 250ms as a worst case. It should be possible to get the impact as low as the server skipping one frame every few minutes. The clients don't need to skip any frames.
I agree, jitter bigger than a synchronization time is worse than high latency. When player have high latency (and I was in top3 on NA Solo ladder in League of Legends while playing from Urals with 220ms), he could only predict the moves of the opponent because what you see is far behind the server state, but with stable latency he knows the exact delay between an input and registering it on the server which puts less pressure to mind to deal with desynchronization between the picture on a display and the actual state.
I agree, jitter bigger than a synchronization time is worse than high latency.
I'll always grant that fast twitch FPS will always have a problem with this. That's not the genre I'm interested in creating games for, and it's not what my server framework is designed to support. (It is real-time action, but the pacing is more akin to RTS than FPS.)
I didn't say that high latency isn't frustrating. But you can effectively shoot the air on the route of the opponent where you'd think he would be by the time server would have your input.
A bit off topic but what does the word 'constellation' mean? A quick Google didn't yield much, and I'm not entirely sure what field it's from. My guess is "a set of connected satellites"? Or is it more specific than that?
That's quite cool. I'm doing my feature at more of an API level. That said, many applications still need to be architected to do this sort of migration well. The turnkey version just guarantees a demo version. (As technology develops, the turnkey capability will increase, but people's demands on the technology will also increase.)
Wait, what? Are you planning to put your game server in orbit? Because otherwise I don't understand what you're asking - a server on the ground will always be "geostationary" - it's the satellites it talks to that will change.
Admittedly I haven't researched it that well, but I'm curious how often they would have to aim their sensors at the sun to receive from a neighboring satellite. I'd have to assume those links would need to be subtracted from the system, which could slightly drive up latency around sun up and sun down for a part of the planet.
The sun is pretty small compared to space, something like .0005% of the full sky sphere, and almost half that time it's covered by Earth. Since there's no atmospheric glare in space, I suspect it's not a problem given decent engineering.
Given communication is point-to-point, and very coherent, I'd think this is extremely easy to solve if glare in the system was a real issue. Aim the receiver through a tube (or array of tubes) painted black, for instance. Certainly easier than building an equally precise telescope.
An LEO satellite constellation has a bad urban/rural problem because most of the Earth's surface is ocean, uninhabited or uninhabitable. In the meantime, people from New York City and Detroit who hate their cable company will compete for network resources for people in the middle.
To take advantage of those thousands of satellites, subscribers will need to install high-performance phased array antennas that will probably cost at least $6000. There will be the capital costs for the space segment, also since the system is just a bent pipe to Verizon, AT&T or whoever your local rent-seeker is, they will take a cut.
Cool idea, but sounds a lot like your typical Elon announcement. SpaceX ia doing great in the rocket business sue to clear advantage regarding development costs (I still have my doubts regarding their true launch costs, so). Pushing them to develop new antennas shifts the focus, not sure if that is such a good idea...
If it's military/aviation/naval phased array radar this is a very different use case. The targets are transceiving from well known locations, not maneuvering to reduce signature. The orbiting target is well above the horizon, not hidden in clutter. There are well defined frequency bands so high frequency agility is not necessary. There are no purpose built enemy jammers to overcome so extraordinary power levels or heroic filters aren't necessary. There are no afterburners or naval catapults to withstand.
About the worse case I know of with the bands involved in this system is rain fade or snow cover.
We already have MIMO beamforming transceivers at nearly disposable prices in the form of wifi routers. I think it's entirely feasible to develop a fixed function civilian phased array at a reasonable cost.
Because they hate the cable company, because some of them have outrageous amounts of money, because some of them would like to have a backup connection, and because they are crammed in tight so even if the takeup is only 1% they still will consume a lot.
Elon should really do a John Henry if he can afford to set it up. Run a head-to-head data-transmission with checksum validation in some theatrical setting. For bonus points he could (if it's possible) run a self-driving car demo where the computation is being done and relaid by a LEO uplink.
Also, I hear what you're saying but... Right now the Algorithmic traders all use fiber and new fiber is constantly being rolled out to support even lower latency connections so I'm skeptical - if it was competitive wouldn't G&S be using it to contact the London stock exchange? Or, is it that fiber can produce lower latency in idyllic scenarios but that congestion pushes the latency beyond that accomplishable by an LEO setup for us plebs?
> if it was competitive, wouldn't G&S be using it to contact the London stock exchange?
They will, but no such satellite network currently exists. Right now, all of the satellite internet services are using satellites in high orbits. That means they can cover more of the Earth's surface per-satellite, and the satellites last a long time. This was necessary when rocket launches cost >$10,000/kg.
SpaceX is drastically lowering the prices of launching satellites ($1k-$2k/kg, Starship will probably be <$500/kg), and they are taking advantage of that by launching thousands of satellites into LEO (Low Earth Orbit). These satellites will have a 5-7 year service life, which will reduce the cost per satellite and allow for regular upgrades via replacement.
Newer hardware and lower altitudes means less latency and more bandwidth than previous satellites. It will definitely beat transatlantic fiber on latency, but bandwidth will be more limited.
I remember reading about line-of-sight microwave links being used for trading here on HN. I think line of sight is the key difference between fiber and radio.
I dont know if I'd call it direct line of site, but low bandwidth directional microwave communication is definitely used over-the-horizon from say Chicago to London. This [1] Bloomberg article has a great rundown on microwave in finance.
Bandwidth is low, but latency beats fibre, and you can bounce microwave off the ionosphere between London and Chicago (and various other routes). This article doesn't mention the cross Atlantic transmissions, but it is possible, and does happen.
Disclosure: I have worked at several of the Chicago based firms mentioned in the linked Bloomberg article.
Edit: grammar, formatting.
I wasnt directly involved in any of the microwave networking, but ask me what you want and I'll answer to the best of my ability.
As far as I'm aware, there aren't any LEO satellite internet providers at the moment (a few in GSO, but the latency there is probably too long to make it relevant for trading), so I think that it just isn't an option. It'll be interesting to see what happens when the first LEO constellations come online.
Serious algorithmic traders use point-to-point microwave links, because the speed of radio waves in air is about 50% faster than light in a glass fiber.
The majority of the latency improvment from these hft networks is because the path taken by them is more direct. Fiber routes follow roads and railroad tracks. The series of point to point antennas takes closer to a straight line.
> So there is a cross over point where the latency of a LEO satellite system is actually superior despite the uplink/downlink path.
There is, but given the rise of the use of edge caching and edge compute for latency-sensitive applications, with edge locations located to optimize access to masses of users, that crossover is unlikely to be actually reached in many of the cases where latency is actually a concern, and Starlink is going to be stuck behind unless it is able to both get edge caching and edge compute on its satellites and get content/service providers to use it, and comsats aren't exactly optimal locations for that.
Latency is also much less important with highly cacheable content. At least, I can’t really think of examples to the contrary. My patience for loading pages browsing is many orders of magnitude higher than realtime uses. Bandwidth seems to dominate in this context.
Latency of multiple seconds, like you can see in some places around the world, is much more frustrating than the kind of latency discussed wrt Starlink.
The lack of a close edge node is kind of interesting, though, so i’m not trying to dismiss your comment in the least.
Honestly I will be fine with bad latency if I can get reliable wireless internet anywhere on earth. If I need good latency, like for playing games, I will go to a location with fiber.
I really, really think SpaceX Internet can do a lot of good. It may force competition. It may give internet access to many countries where it's not an option. It may even help fight censorship, or open the door to an alternative to the current internet network.
>many important routes will have significantly lower latency than any feasible terrestrial system
Is that accounting for recent developments in hollow core fibers?
>"The researchers successfully demonstrated the first high-capacity, low-latency data transmission experiment performed using a hollow-core fibre. In this, they found that light propagated 31 per cent quicker than in a solid core fibre, increasing from 70 per cent of its full speed in a vacuum to 99.7 per cent. To put this in context, this means that data propagating in this fibre would arrived 1.54 microseconds/per km earlier that it would in an equivalent length of conventional solid fibre. Not only did the light almost travel at its fastest possible speed, but it did so with a very low loss of 3.5 dB per kilometre."
> Is that accounting for recent developments in hollow core fibers?
No, it doesn't.
You're citing a story from 2013. Has this seen deployment in the field? I haven't found any evidence of this. That makes me wonder what is missing in this story.
Also, I would think that the first transatlantic cable of this stuff might be kept pretty exclusive, given the economic opportunity presented by pissing around on the stock exchange.
Why do you think that satellite to satellite routing will be particularly fast? There are a lot of hops, some satellites are moving relative to one another, and the satellites are power and bandwidth constrained. It sounds like a latency nightmare.
Consumer connections will use bent pipes. Satellite to satellite links are limited and will be mostly used by high paying customers like high frequency traders.
Depends on the frequencies being used. Starlink is in the ku and ka band so it will be affected by weather, especially heavy rain or snow(called rain or snow fade in the field)
Standard solution to rain fade is to make sure you have a power budget and can ramp power when heavy rain starts.
Given that speed of light is ~3×10⁸ m/s an additional ~1,000 km (10⁶ m) up and down and back again would increase latency on the order of ~10 ms (10⁻² s).
~10 ms of additional latency isn’t wildly out-of-sync with real world latencies of ~40 ms within North America and ~70 ms across the Atlantic. [1] And if we factor in the ~30% reduction of speed of light in fiber, the delta might actually be less than ~10 ms.
Local latency might be okay (worse then fiber, slightly worse than cable) but using space based routing is going to be a poor experience. There are a lot of latency-adding hops in space, and the terrestrial link bandwidth is so poor that popular destinations (LA or NYC) are going to be congested at their terminal endpoints, meaning you'll go the long way around and exit the satellites at a farther, more rural base station than is ideal, and use fiber for the final hops.
The problem I have heard isn't so much latency but path to profitability. Unlike GEO satellites, LEO based internet is not going to be fully operational until a significant number of satellites are up there to provide continuous coverage at a single point on earth. Financially, this makes for a very front-loaded-capital / debt-intensive business which will falter unless subscriber numbers and technology all pan out exactly as estimated.
If you could actually compete against fiber I feel like the funding would be very easy to acquire if your first step was linking up the various stock exchanges - those guys pay up the nose for even slight latency decreases.
This isn't going to be lower latency than existing low latency solutions.
EDIT: For more context, the old low latency fiber path between Chicago and New York was under 7ms, and current low latency radio solutions are under 4ms. SpaceX's solution is marketed as being "as low as 25ms".
Even in voice chat's case latency isn't a huge issue until you get really high numbers. But you're right, even higher latencies can fit the 80% or even the 90% use case.
A misconception probably due to an overestimation of how far away space really is; the ISS only orbits at roughly 240 +/- 30 miles, and the (admittedly arbitrary) boundary of space is at 60 mi (100 km).
The article implies more uncertainty than there is. To my knowledge everyone agrees to define the edge of space at 100km (about 62 miles), with the exception of the US where for historical reasons the edge of space is seen as 50 miles above sea level. There is no international agreement, but even though the line is arbitrary there is no huge variety of widely held opinions.
And Ground infrastructure doesn’t exactly take a straight path either. Add 5-10% slack in the line for loops/splice trays/pole movement, and then going around artificial and natural barriers...
When AWS introduced Ground Station [0] I was unsure as to their motivation. Looking back on it, this kind of endeavour might have been the impetus for the service. In fact, given how much of the "Internet" depends on AWS, SpaceX using Ground Station might actually lower latency to your favorite website.
I feel like a majority of people falsely think the cell phone in their pocket talks to satellites anyway. So a space delivered ISP might not be a big shock for people.
GEO - Geostationary equatorial orbit (further from the earth, more efficient in terms of energy required to maintain a fixed position[1])
SOL - Speed of Light (a limiting factor in fiber optic communications - and over the air communications as well)
[1] From reading a bit, maintaining a fixed position relative to the ground at lower altitudes involves a constant velocity adjustment in the form of fuel expenditure - the equilibrium for each orbital period corresponds to a single altitude, so different orbital periods (when minimizing fuel usage) imply different distances.
Re [1], you generally can't do fixed positions anywhere else but GEO. Trying to stay stationary at a lower altitude would require using amounts of fuel that are way beyond what we can put in space.
Note that GEO satellites do carry fuel with them for "stationkeeping" - between errors in navigation, variation of Earth's gravity (due to it's irregular shape and composition) and influence of solar radiation and other celestial bodies, those satellites do have to occasionally and very slightly adjust their orbit to stay stationary.
I wonder if this is a temporary software design problem. I mean, we have response time to burn these days, so we design with that in mind. If latency became a fact of life due to demand for a better deal on Internet access, maybe people will figure out how to make software that doesn't depend so much on a tight server loop.
It will only take a few real customers talking about the latency being fine to make this a non-issue. It's very easy for people to test on their own. I doubt they'll have to do much specific marketing about this issue.
Reminds me of the story recently which mentioned Grace Hopper and her famous visual representation of how far information could travel in a nanosecond when answering a question about why satellite communications takes so long.
Sorry no offence but why is this even a conversation? I use Hughes which is geostationary. 600 to 900ms latency. That is around 35000 km altitude. These will be hundreds of km altitude. Kinda basic math to get the answer here.
Latency's not going to be a problem. What is going to be a problem is what nobody is talking about: LEO satellites move. This means the downlink antenna has to have motors and move too, or it has to be a phased array and be expensive.
There isn't any question about the type of antenna. The details have been filed with the FCC. The antenna will be phased array.
Obviously there is a high front loaded capital cost to developing a phased array transceiver for this system. The scale of the market, however, is vast; hundreds of millions of units. I believe the per unit cost of manufacturing these transceivers will be low due to this scale.
I can't know that however, so we'll have to wait and see.
Why hundreds of millions? At most this service will have a couple million people on the entire constellation if you want the speeds musk is saying. Otherwise, you have much lower speeds and cram more people, which is a trade-off all satellite technology has.
We can't compute credible figures at this point because a lot of the technical information is proprietary and the business model isn't known. I don't believe Elon has committed to any specific bandwidth; searching yields claims of "up to" 1 Gbps.
Given the rates cited here[1] (20 Gbps/satellite) I seriously doubt that 1 Gbps is going to be offered at a price level that allows it to be widespread. More likely we'll see service offered in the 10s of Mbps.
So the best we may achieve is some napkin level estimates. Let us assume 100 Mbps as a realistic subscriber rate. 12000 satellites[2] * 20 Gbps/satellite * 100/1 over-subscription (typical, see here[2]) / 100 Mbps = 240 million theoretical subscribers.
Obviously every figure here is open to endless dispute, but we're in the right order of magnitude. I believe this is the scale Elon is thinking at; he's trying to fund interplanetary space travel with this. In any case there will need to be a couple mountains worth of transceivers for the plan to work, and making fixed function electronics at that scale is typically highly cost effective.
I'm on a small island in the Pacific. If I can get 100 Mbps, by any means, whatever the latency, it will competitive. Right now I pay for 25, the two ISPs on island swear they're building out to 50, and I average 15 down and 1.3 up. my latency sits around 250-300 ms to North America and 150-250 to Asia.
Your math left out the biggest factor, which is useable bandwidth. Most satellites will be over water at any given time, so the number of users will be far less. Any you're talking about full build out, which is a decade away. Internet consumption has been growing nearly exponentially.
That's a great point. Figure 80% of the Earth is ocean, 240e6 * 0.2 = 48 million subscribers. Still large enough to justify, for instance, the custom ASICs necessary to achieve a low cost phased array.
I'm sorry but you are incorrect. You cannot innovate your way around the laws of physics. Do you want 5 Mbps from a LEOSAT? Fine, you need a pointable antenna. An Iridium-style omni antenna cannot accomplish this. The S/N ratio is simply too low.
I suggest you study information theory and antenna theory. What you are suggesting is theoretically impossible. If a satellite could paint the continent with a megawatt, it might work. But satellites transmit with tens of watts, which gets spread over a large geographic area. The ground antenna must be pointed for decent bandwidth, either physically (with motors) or virtually (phased array) to achieve the requisite S/N ratio.
Your deceptive edits are...deceptive. The “it might work” was preceded with a hypothetical condition and then followed with the real condition. It wasn't “its theoretically impossible but it might work”, but, “its theoretically impossible; if satellites could carry transmitters two orders of magnitude more powerful than they actually can, it might work.”
That's not what "theoretically impossible" means. You literally just described a scenario where what I said would be theoretically possible, based on your own understanding of the technology, which is decidedly incomplete.
You also didn't answer the question about your expertise, I'm assuming because your answer is, "No". Maybe leave the correcting of others to the actual experts...
> That's not what "theoretically impossible" means.
Sure it is, if the hypothetical is pointing out a constraint on the boundaries of theoretical impossibility (or, in theory, if the hypothetical is itself possible to describe but theoretically impossible because of physical limits, though that doesn't appear to be the case here; there might be a theoretical lower limit on the size of a transmitter of the require power output or the supporting power system, but in theory there is no limit to the size of a satellite except the bound at which it becomes the primary because it's larger than the thing it is supposed to orbit.)
> You also didn't answer the question about your expertise
A careful examination of the thread will find that no such question was previously raised. There are more than two people on HN, so just because you get a response that doesn't make the person responding necessarily the person to whom you were responding. HN shows comment authors handles in case you ever need to know to whom it is you are responding, which you might want to do before attacking them based on assumptions about their identity.
LEO vs. GEO networks are like plutonium bombs vs. uranium bombs.
One is simple to engineer, but resources are limited and expensive. The other is extremely complicated to engineer, but resources are cheaper and more available.
In this case GEO systems are simple: satellite is stationary (ignoring slight drift which causes microsecond changes in latency), beams are stationary, antennas on people's roofs have no moving parts. However, the GEO satellite is extremely expensive, the spectrum it is using is expensive, and the GEO orbital slot is expensive. Also, it's so far away that it's high latency making online gaming nonviable.
LEO systems are extremely complex by comparison: satellites are moving, thus the beams are moving, antennas are moving (motor driven, unless using electronic phased array which are currently super expensive). With everything moving you have to do constant beam hand offs, doppler correction, etc. But, the satellites are much cheaper and the latency is much smaller.
Kudos to whomever can pull it off - there are several contenders other than SpaceX like OneWeb.
I believe the plan is for phased arrays, at both ends, at substantially lower prices than are currently commercially available.
Since SpaceX has already built the "first batch" of satellites (delivered to launch site as of a few days ago), one has to imagine they've largely solved the manufacturing problem and reduced the cost from 250k per antenna.
IIRC, OneWeb's initial plan was to use phased arrays as well, but it proved too expensive and they switched to mechanically steered antennas (at least for first gen).
Phased array is definitely the way to go if you can get cost down. No moving parts means fewer hardware/mechanical failures and less noise
I can easily imagine economies of scale in MMICs (Monolithic Microwave Integrated Circuits) bringing the price down enough to make phased arrays affordable. I sincerely hope it happens.
Why are electronic phased arrays so expensive? I am no radio expert, but it seems that the pricey bit might be the engineering required rather than cost of production. From what I remember of my polar calculus, it sounds like a lot of painful calculus written once and fed henceforth into a computer.
You do not need a high-end FPGA; you need a bunch of small antennas (potentially extremely cheap, as these kinds of antennas are often microstrip antennae etched into PCBs), and a bunch of microwave-rated components such as mixers, phase-shifters and capacitors. The phase shifters allow you to add up the signals in such a way as to form a coherent beam in a certain direction, this is known as beamforming [0], and with some admittedly complex precalculation, an electronically-steerable antenna array needs nothing more than a simple microcontroller to set the phase shifters for the desired array orientation. Of course you would want to adaptively steer it based on received signal, but this can be done without the need for fancy FPGAs; your receiver signal chain will include all the mixers, demodulators and signal processing elements needed already baked in silicon; similar to how a WiFi chipset does channel adaptation by analyzing the received signal without resorting to high-end hardware, the kind of system that SpaceX is building does not require particularly exotic hardware (although it would be custom, and expensive to develop).
Speaking of which, there's a neat project that sneaks into a particular Intel chipset and extracts the CSI (Channel State Information) from the wifi hardware so you can actually do things like estimate which frequencies are being attenuated [1]. It's out of date, but still shows the kind of live, complex, signal analysis that is possible with commodity-priced hardware.
In short, I think it is certain that a base station can be built for <$1000, and likely that it can be built for <$150, although without knowing the precise specifications, it's hard to say. We did a case study on this in my antennas course in grad school 3-4 years ago, and our ending numbers on our prototype designs (not fully built and tested, of course, but simulated and spec'ed out with real-world pricing) were around $150. I am certain that our design as it was would not work, but something similar to it likely would. ;)
It also needs to be rad-hard for space. Terrestrial FPGAs are subject to occasional "SEU" (single event upsets)[1] which can arbitrarily affect behavior because gates can flip. Robust terrestrial FPGA systems have to handle SEUs; you have to imagine that these events are more frequent in space and need to at least be handled.
(This may something you already had in mind, summarized as "high-end FPGAs;" I just wanted to add some interesting color some folks might not be aware of.)
In LEO it doesn't need to be rad hardended, especially for something that isn't life critical (compared to say, the control system of a space shuttle). At this altitude, the atmosphere and magnetic field provides a lot of protection still.
At the very least SpaceX would test the devices to see what effects the higher radiation would have. However it's not unreasonable to just have the software detect and reset itself, if a high energy event is detected. There are going to be a lot of these satellites and a lot of redundancy in coverage, so if one is down for a few minutes it's not that big of a deal.
Yes, as long as radiation only causes upsets and not permanent failures — satellites are somewhat expensive — and as long as software can detect faults and reset.
Sure, but that isn't saying an awful lot; most satellites are very expensive. SpaceX would want to weigh the cost of hardening the system against radiation versus the cost of another launch to replace failure(s). I'd guess radiation-hardening of some kind (at least sufficient to prevent most permanent damage) would win out in that calculation, but I'll happily admit I don't have any particular factual basis for that guess.
I'm not sure 4000 is enough to break even on ASICs, but I'll admit I don't know much about the costs of either high end FPGAs nor ASIC production at quantity 4000.
From what I am reading here, a large part of the cost is up-front with chip design and setup. I suppose it depends on pricing. They also may wish to sell more after those four thousand units.
LEO satellite handoff is tough because you effectively need two antennas: One points at the "old" satellite while one points at the "new" one. You can achieve this with a single phased array antenna divided in half and controlled by software, but each half must still be large enough to give the needed S/N ratio.
Iridium uses an omnidirectional antenna which is fine if all you want is 1200bps. But if you want 5Mbps, you have to point the antenna. So Iridium is not applicable here.
Cell hand-offs don't happen nearly as frequently as they would for an LEO constellation.
The orbital period for a satellite at 550 km is ~01h 36m. That means any given satellite is going to be visible for a very short period of time, which means hand-offs will have to be extremely frequent.
That's per satellite; each satellite is going to have multiple beams, so you'll have to do a beam handover like every 15 seconds and a satellite handover every couple of minutes
"SpaceX just received approval from the FCC to launch 4,425 satellites into space to build a low earth orbit network of satellites to sell home Internet.
Unlike current satellite Internet, these devices will be in a far lower orbit and offer far faster speeds without the data caps current satellite systems use.
The goal is that this new system will offer robust high-speed Internet, especially in developing countries and rural parts of developed nations like the United States. While you may not be running out to buy this if you have fiber Internet, it could bring true wireless Internet options to Americans who currently have no real options.
“This approval underscores the FCC’s confidence in SpaceX’s plans to deploy its next-generation satellite constellation and connect people around the world with reliable and affordable broadband service,” SpaceX President Gwynne Shotwell said in a statement.
SpaceX has already launched several test satellites to prove the system works. Now they have permission to move forward with a larger rollout of 4,425 satellites.
The system also promises to help relief efforts that currently spend hundreds of dollars a day for 5 Mbps Internet. With this system, relief workers can access high speed Internet even in areas hit by a major disaster."
For the frequent commenters about people not understanding latency, or the differences in technical terms around bandwidth, LEO/GEO, etc, imagine this: You may not be an economics or fiat currency expert, but given a choice of US dollars or Mexican Pesos, which would you pick? How do you know this? Do you work for the government or post frequently on the currency version of hacker news? No. You learn from people around you pretty quickly. If you're in a small town, you have limited options for bandwidth. There's Hughes Net (Satellite crap (high latency), but works if the only option) there's a new small Cable provider, there's DSL (phone company), etc. People chat, they gossip, they figure out how to get the best connection, in some ways embodying things straight out of movies like Hackers/The Matrix, even though they may own the local feed store. It's interesting to see. Don't underestimate people.
I have a friend who just started working on the assembling of these satellites and they are hiring like gangbusters. I was initially dubious that they would be able to make their number goal but they have people working 6 days a week 16 hour days to scale up to this goal. 4000 is a huge amount of things to build that you can shoot on top of a rocket. Not sure the longevity of the hardware.
I'm pretty sure he meant the production line is running 96 hours a week. They probably have it split between 2 shifts so each person is only running the line half the time.
2 shifts but the push is def to have people work
more hours. Seems the main goal is figuring out how to make all the satellites with relatively unskilled staff(relative to satellite building. prior to this my friend worked at a bike shop and construction and has a BS in physics).
> I was initially dubious that they would be able to make their number goal but they have people working 6 days a week 16 hour days to scale up to this goal
If they have to make people work 96 hours a week isn't that evidence against them making their goal, not for it? If they were progressing according to schedule, with buffer for unexpected events, surely people would be working sane and sustainable work weeks?
The solution to that problem is to get municipalities to exit their monopoly agreements with broadband providers.
Spending more tax dollars on satellites isn't helpful. That just gives your representatives an easy way out in the near-term, and probably results in everyone getting upset over wasted money in the long term.
How often do you need to call the customer support? I have had Comcast for 6 years now and I call them once a year to renegotiate the deal or move the connection.
Everyone is super excited about this and I am sure its going to capture a significant market, but you have to realise what are alternatives and how much they cost.
I expect them to be utterly unaffordable at least for first half of decade.
Their biggest competitor is Iridium which offer similar service at $150 per 2kbps. I will let you extrapolate real life prices from here.
SpaceX should be able to undercut that some since they can launch their satellites at cost and using a booster that's already been up once or twice really brings that cost down.
Bigger less profitable userbase vs larger more profitable user base. The question is if the bigger userbase option is big enough to make overall profits larger than they would have been with the smaller one. I have no idea.
Heck, I already have FIOS, but if it's reasonably priced I'll subscribe just to support it (and to have a backup). Musk is basically the closest thing we have to Tony Stark. If that's not worth supporting, then I don't know what is.
Interesting, I see reports of latency of 60ms on average [1]. Starlink claims it will offer as low as 25ms [2]
Is 35ms a significant value proposition, considering 5G is on the horizon?
> As of March 2019, HughesNet's average download speed is 11.04 Mbps. Throughout their coverage area, the average latency on HughesNet Internet speed tests is 61.87ms. For context, wired terrestrial Internet connections usually output latency results in the 5–70ms range. [1]
GEO Satellite is 22,236 miles above sea level[1]. Speed of light is 186,282 miles per second[2].
Therefore the absolute fastest information could travel on a GEO network is 22236/186282 = 119 milliseconds (one way at the speed of light), which is 238 ms round trip. In reality there are going to be internal and network latencies so I would expect something more like ~300-500ms RTT.
That's right. Geo will typically be around 600ms. The speed metric is incorrect/misleading as well. Both Hughes and ViaSat offer multiple speed plans that are vastly different. You can't simply take an average, or your speed isn't representative of what the service could do. Of course, satellite internet will pack a lot of users in there to fill up the satellite. I don't be naive about that, SpaceX will do the exact same thing.
If your cable service offers 10, 25, 50, and 100Mbps plans, how is an average speed at all meaningful? It's just representative of how many people sign up per plan.
Yeah but... it's claiming information can travel faster than light...
It must be averaging in terrestrial network latencies or something, because GEO satellites are literally hundreds of light-milliseconds away from earth
I'm genuinely curious, can you have it without your landlord (if you rent) approval and also install the ground transciever without HughesNet technicians? Sometimes they refuse to install in particular locations on the grounds of perceived landlords disapproval (?)
Not a lawyer but there is definitely a law in the US which prevents landlords from not allowing tenants to install satellites for television. I'd imagine that the same law might cover generally any consumer telecommunications equipment
Internet traffic via a geostationary satellite has a minimum theoretical round-trip latency of at least 477 ms (between user and ground gateway), but in practice, current satellites have latencies of 600 ms or more. Starlink satellites would orbit at 1⁄30 to 1⁄105 of the height of geostationary orbits, and thus offer more practical Earth-to-sat latencies of around 25 to 35 ms, comparable to existing cable and fiber networks[51] (although transmitting a signal halfway around the globe takes at least 67 ms at the speed of light).
the biggest win here are productivity gains. After high speed internet is available, you'll be able to work in the bush with a laptop. away from ridiculous rents and rent-seekers.
While the DPRK would have no means of doing this, the PRC could quite plausibly launch its own jammer constellation if it became enough of an issue.
The most interesting aspect is that an import ban on LEO satellite modems becomes exponentially harder to enforce when you’re the only country that can manufacture them at scale in the first place.
I'm 90% confident that if SpaceX ignored international (and Chinese) law and started broadcasting into China without permission the PRC would be delighted at the excuse to test anti satellite weapons instead of trying to jam them.
Of course, SpaceX wouldn't dare risk the international firestorm of doing so intentionally. But if the service were available in Taiwan, mainland China is only about 100 miles away across the Taiwan Strait.
The connection might be slow and spotty from Fuzhou, but all you'd need is a modem sold out the backdoor of a factory and an account created in Taiwan (perhaps a friend you Alipay for the subscription), and you'd have unfiltered internet in eastern Fujian.
Repressive regimes will ban importation and possession of the antennas, and will prevent citizens from paying for services. A few courageous dissidents will defy the bans but not enough to matter.
Sure - if the want to risk China/NKorea/Iran shooting those satellites out of space. Seems a bad gamble so I doubt they'll provide service to those countries.
Yes, this is going to change the world in a big way. High speed global communication is a paradigm shift. If SpaceX cheap reusability and Tesla all-electric really end up doing the things they promise on a huge scale, then Elon will be 3 for 3 on truly world-changing advancements.
Internet was supposed to change everything yet we are stuck in cesspool of misinformation.
100% sure Tesla will either apply great firewall in China or just shut sats down while they are there, because China will threaten shutting gigafactory.
Your going to have to give a lot more details than that blanket statement because I have been following starlink closely ever since it was announced.
Oneweb is their main competitor who has already launched test satellites but they are going to launch on other companies rockets which are much more expensive than spacex's especially now that spacex is getting reusability down.
Amazon just announced their constellation plans and they either have to launch on expensive non-spacex rockets or have to use blue origin which while they are planning to have fully reusable rockets, those are still years out.
What are the other 3 companies that will be out first and/or have higher throughput and/or how are Amazon/Oneweb better?
Oneweb, telesat, ViaSat, o3b (mpower), and Boeing have all announced. A study from MIT showed telesat's to be the most cost effective from the LEO bunch [1], which is important since it's not clear SpaceX has a path to revenue [2]. and if you've been following starling closely, you know that they will not have anywhere near their full deployment for over 5 years after the first launches. the entire fleet is required for the capacity they have been touting, not to mention the coverage.
And the argument that SpaceX has some kind of moat because of their launch business is simply not true. there are many launch providers out there, and launch costs have gone way down partly due to SpaceX, but also because satellite orders have decreased significantly. SpaceX as a company, needs as much revenue as possible to fund the satellite venture, since their entire company is depending on it. The launch business is not sustainable in providing enough revenue in the future to keep them in business. so SpaceX will have to fight for business from all the other satellites just as much as any other company.
> A study from MIT showed telesat's to be the most cost effective from the LEO bunch [1]
I just read that article and it makes no claims whatsoever in relation to costs.
> which is important since it's not clear SpaceX has a path to revenue [2].
Path to revenue? What does that even mean?
> if you've been following starling closely, you know that they will not have anywhere near their full deployment for over 5 years after the first launches. the entire fleet is required for the capacity they have been touting, not to mention the coverage.
US/Europe coverage is going to be their primary initial target as that is where the most money is and that requires a significantly smaller amount of satellites. Care to enlighten us on what other companies are planning to launch production satellites like spacex is doing next month because the only company I am aware of that has even launched test satellites is oneweb.
It gives a bandwidth efficiency ratio, which is directly tied to cost since the more efficient per bit the system is, the cheaper it is to run. If telesat's is 4x cheaper per bit, how would SpaceX compete?
Path to profit.
You are saying SpaceX launch a handful of these satellites is really going to have any effect?They already launched some and they had propulsion problems. They need upwards of 500 of these in the air just to compete with satellites that have been up for multiple years already.
> It gives a bandwidth efficiency ratio, which is directly tied to cost since the more efficient per bit the system is, the cheaper it is to run.
The source you linked said Telesat had a 4x Gbps/satellite bandwidth over spacex which is not directly tied to cost. Telesat has no mention of satellite weight and spacex plans to launch 40x the amount of satellites as Telesat for their initial constellation and 100x at full capacity if I recall correctly.
> Path to profit.
Spacex has reusable first stage rockets. I don't see how any of the other mass satellite constellation companies that you mentioned can have better margins than spacex.
> They need upwards of 500 of these in the air just to compete with satellites that have been up for multiple years already.
Do those 5 companies you just mentioned somehow don't?
Blue origin will have the same, or cheaper costs by the time it matters. Not sure what your last comment means, but 3 of those 5 are slated to have far more capacity in the sky by 2022.
Read the study again. It's useable capacity. You cannot use the 20Gbps number SpaceX advertises.
The number of satellites is not relevant. It's a single parameter a large number of them which describe how well the constellation will perform. Please see here for more detail:
The satellites are not the hard part, even though they are extremely hard. The hard part is going to be getting a suitable user antenna for a low enough cost that they will make the money back. So far they have not spoken publicly about their user terminal or cost, other than a couple sound bites musk said years ago about how low he wants the cost.
I can actually see this working as a backbone provider. Take any underserved area, rent space on cell phone towers or water towers or grain silos, and deploy an all-in-one kit that has the Starlink antenna along with a WISP transmitter and solar power. Also would work for apartment owners who want to get an additional revenue stream by being the sole provider of internet to their tenants.
So what? The entire purpose of Starlink is to increase global demand for launch capacity. That's the only way they're going to reach the economy of scale to be able to actually reduce launch costs as much as they're capable of. They can break even or even take a loss on Starlink and still achieve a valuable strategic goal.
What about rainy clouds and thunderstorms? While i want to be outside in sunny weather and work on my laptop during rainy day - that's when the connection quality is worst?
The target price means nothing. Musk hasn't talked about them in years. Other companies have tried (and failed) and low cost phased array. Until they're delivering at that price, think of it like musk's original Tesla production rate predictions.
Google image search "iridium hotspot" and "bgan". They range in size from a small ipad to a large ipad. Pretty reasonable for global connectivity (although not built into a laptop's frame).
And the starlink antennae they "hope to get down to the size of a pizza box" (which also of course needs to be powered). This is not a mobile solution.
If I can fit it in a pelican case in a checked piece of luggage (62 linear inches, up to 50lbs), it’s mobile enough. Carry on luggage compatible would spoil me.
It can't. The size of a receiver is that of a pizza (this is the only way I've ever seen it described, I wonder if there is a more precise description somewhere) not that of a cell phone antenna.
It might contribute to providing backhaul services making cell-towers cheaper to deploy, and it might enable things like sticking an antenna in a vehicle, but it can't provide 4g style cell phone service.
Would it be feasible for them to build standalone cell towers of their own that connect to these space networks? So rather than "no cell towers at all", the benefit they provide is "no cables at all". They would just go around to remote areas and build towers without needing to lay down the cables. (disclaimer: basically don't understand this stuff at all haha)
Random twitter user (Anner J. Bonilla🇵🇷 <more emoji's, for some reason only 1 renders on HN>)
> can Starlink be used to back haul LTE/regular cell in rural areas or emergency situations/disasters? Seems like a great thing for disasters where back haul is damaged but not sure how useful it be due to bandwidth/latency?
Yes! Many comments on r/spacex suggest that being a good use case for them but they have one major downside. Weather can affect satellite network connectivity which brings their availability down a few nines and many people expect most everything to run 100% of the time. I know growing up, I convinced my parents to try out directtv and my dad always got so mad when the weather caused the satellite tv to go out so it isn't perfect. Therefore, I don't expect it to be used by most people unless their only other opens are hughesnet or dsl.
Yeah, that's basically feasible and your intuition of the cost-savings / requirements is accurate. A cell phone monopoly doesn't have any incentive to pass on those savings to customers, but maybe a small group could band together and buy a portable base station to share.
Remote towers often have wireless backhauls anyway. But if you only want a cell or two of coverage surrounded by a vast dead zone then it's likely viable somewhere.
No, it's impossible. Antenna theory dictates what the size of an antenna can perform at. Without significantly reducing the noise temperature of the antenna much farther than anything else out there, it will never happen. And noise temperature is pretty much guided by physics at this point.
I'm not a hardware guy, but i doubt it. They would need to reduce the size and power requirements by an order of magnitude each of which we are currently struggling to do nowadays. Most importantly though, the wavelengths they are using i do not think penetrate buildings well and I don't think any of other wavelengths can effectively transmit that much bandwidth through buildings from space efficiently/economically.
Not only that, but phased array relies on the radio signal hitting different antennas at different times. So the array of antennas have to be spaced a minimum distance apart depending on the wavelength used.
folks, the latency of other space-based internet services is because you're talking to satellites out at geosynchronous orbit. starlink is low orbit, and depending on the route your packets need to take, might be lower-latency than ground-based links.
The sheer ambitions and speed of execution of SpaceX (and even Tesla) is exhilarating. I hope they make it happen and put a dent in the deeply entrenched incumbent monopolies who are abusing their position. I would buy the service in a heartbeat.
What are the odds that all Teslas magically get Starlink? Seems like a nice way for Musk to prop up one of his ventures with service fees from another.
I could see this actually reduce the costs in fact. Right now Tesla's all need gsm/lte support for updates. This would let the updates work anywhere in the world without the other infrastructure that's needed.
This is right on. And I suspect it will also be used for Tesla to Tesla communication so Tesla vehicles share information (slow down ahead, etc) with each other.
There are possibilities that can be enabled if the vehicles can communicate with each other. In the absence of other alternatives, using Starlink may be the way to do this.
Musk has specifically said that this is not a mobile solution and won't be used for his vehicles. The antennae is too large to be practical (the size of a pizza).
SpaceX won a $28.7 million fixed-price contract from the Air Force Research Laboratory for experiments in data connectivity involving ground sites, aircraft and space assets [0] so they definitely are looking to put these onto vehicles.
Who else besides the FCC needs to approve SpaceX launching over 4,000 satellites into space? That seems like a fairly significant number of satellites, but admittedly I am a layman in this area.
The ITU as well. Part of their proposal involves reuse of spectrum currently allocated to geostationary satellites, and the mechanism for noninterference is physical separation: while they may transmit on the same color as a GEO-sat, they won't be simultaneously visible from a normal antenna for GEO use as they will point in a different direction. The GEO-sats (and their spectrum allocation) is confined to the ecliptic, while these LEO-sats will be transmitting from any direction except overlapping the ecliptic.
It is a pretty significant number of satellites. For whatever reason the FCC has taken up the role of regulating satellite collisions and such, and if you go dig up SpaceX's fillings you can see them discussing mitigating issues related to this (keeping probability of a collision for the entire constellation less than the acceptable number for a single satellite, making sure the satellites burn up on re-entry to mitigate "a satellite fell on my head" risks, etc).
Each country more or less is responsible for regulating itself. The International Telegraph Union sometimes comes into play for spectrum issues, but I think most of their influence is in GEO since they handle slotting there.
I'm curious specifically about the prospect of circumventing firewalls in China or other places where internet access is heavily restricted and censored. I imagine that China could tell the US government to tell SpaceX to cut it out and cite various relevant international treaties, but in a lot of ways it's more of a political question than a legal one. I doubt many people outside the North Korean leadership would object to providing Internet access to North Koreans, for instance.
China has the ability to shoot satellites out of the sky. Now if they have the political will to do so remains to be seen. But they can also easily jam them in their own backyard.
How would the Starlink solution compare to Iridium's NEXT? Is Starlink simply a larger-scale version of the same idea, or is there some special sauce in Starlink vs NEXT that would differentiate their potential use cases?
From what I can tell, they are both LEO solutions but Iridium is using far fewer satellites to achieve 100% global coverage. I assume there is some reliability metric or other more obscure aspect that would make someone want to choose one over the other for some particular application.
The only tangible differentiator I can come up with right now "in favor" of Iridium (aside from the fact that it's already up there and working) is the multi-mission aspect of the constellation - science experiments, DoD contracts, ADS-B for Aireon, etc. But, for someone who is seeking an affordable, satellite-bound 50+ mbps pipe to the internet, a 1000-10000 satellite constellation sounds like it's more appropriate.
One big differentiator is the nature of the antenna needed. The phased array antenna for starlink is apparently the size of a pizza box. Iridium satphones are comfortably handheld.
It has to due with the phased array antennas being used, which is basically a grid of antennas where each receives the signal at a different time (due to speed of light propagation). By delaying the processing of signals an appropriate amount from each antenna, all the individual signals can be combined to be the equivalent of pointing a dish antenna directly at a given satellite all the time as it is flying overhead.
If you think of this as a graph database problem, it becomes pretty easy to solve. I'm sure this is how they will load balance between the satellites that you can see in the sky as any one moment.
Even better, you can pre-calculate this as long as you know where all the base stations are. Dynamic registration should be pretty easy to do too as it will need a GPS chip in it.
Less infrastructure. Why build towers when you can buy internet from space. Also you can sell world wide in seconds. You can sell it in china behind the firewall. In india in the middle of nowhere. In south america. All with no towers or wires.
FWIW, the OP's wording was confusing. It took me a minute to realize that they were talking about something like Google Fiber, not literally running a wire from Earth to an orbiting satellite.
I'm curious if this will become an ideal service for hackers or others seeking to hide identity to use as a random and mobile location from which to operate? Assuming it becomes ubiquitous as there are multiple companies racing to offer these "constellations".
You are triangulating yourself, while broadcasting kinda loudly to the sky. So not directly. This is no hackers pancea. But a network of them hidden on rooftops connected via side channel may find effective use.
I do wonder a bit why why they need THAT many satellites. Assuming an orbit at 200 miles altitude, we have a horizon distance of about 2000 miles. Comparing the area of that 2000 mile radius ground patches with the surface of the Earth, we need about 10 such patches. Filling in the gaps between patches might require 10 more satellites. Naively I would have assumed that orbital mechanics costs us another factor of two, so fourtyish satellites required. But they plan to launch more than 4400 satellites. More than 100 times the naive estimate. And at the cost involved they don't do it for fun. Where does that discrepancy come from?
Other people mentioned the issues with antenna obscura— buildings, walls, trees etc can all get in the way.
If you connect to a satellite at an oblique angle, it is also much further away. A satellite in a 500km orbit is 500km away from you when it's directly above you. But when it's on the horizon, it can be more like 2500km away.
This adds a little bit of latency (maybe 10-20 ms). It also hurts the signal, since going through atmosphere attenuates signals more than going through vacuum. Especially for Ka band signals, which particularly weakened by water vapor.
On top of that, SpaceX needs to have redundant coverage over an area. You don't want your customers' internet to stop working because a bit got flipped on one of your satellites or a thruster blew up unexpectedly. Also, a single satellite may be able to handle Alaska or Siberia but have bandwidth issues handling the state of California.
If you run the calculation the other way around, every satellite has to service a ground patch with about 380 miles radius. And your antenna has to swivel to a point that might be more than 60 degrees away from zenith. So every obstruction of more than 30 degrees above the horizon will lead to at least intermittent disconnects.
More bandwidth and better resilience against loss of individual satellites? Similar rational to how when you install a wifi network in a high density usage environment you want to use a lot of lower power access points each covering a small area to get better throughput for a large number of users rather than trying to cover the whole area with a small number of higher power AP that each cover a wider area.
This is just a guess, but maybe to simplify the tracking requirements on the ground?
With a minimal satellite system, your tracking needs to follow satellites all the way across the sky, and probably also needs to be able to rapidly make large changes in where it is aimed.
With a very large number of satellites, a ground station might be able to get by with only having to be able to track within a small part of the sky.
If you have enough that there are many of these small areas that always have a satellite in them distributed all across the sky, then even places that have a lot of buildings or trees blocking much of the sky should still have some patch they can view that works.
Two reasons: more bandwidth, and more coverage in a specific region. One of the biggest downside with a LEO constellation is that only a few satellites are covering a given area at a time. Most of them, by far, are over water, where there's likely little to no usage. So because of that design, do you have to launch a lot of satellites to make up for the lack of throughput in the single areas.
Area of earth is 170 million square miles. 2000 mile radius patches have 12.5 million square miles. Even assuming perfect tiling, 10 wouldn't be enough.
Throw in realistic angle limitations (not horizon) and coverage per satellite rapidly decreases
Ok, make it 14 instead of 10 then. That's a small correction. Filling the gaps on the other hand does not require a factor of two, but only 2 \pi / sqrt(27) or about 1.21. Multiplying the 14 with that gives us 17 instead of the 20 I estimated. I don't want to squabble about 20% here, but ask about the factor 100 discrepancy between naive estimate and projected number.
That is because you’re expecting ground access points to magically communicate with a satellite at 0 degree elevation. With a realistic elevation to deal with obstacles, diffraction, and electronic steering limitations, you’ll end up with a radius of coverage closer to 200 miles, which would give you that factor of 100. This shorter radius also limits losses due to distance attenuation. Your naive calculation assumes the limiting factor is the curvature of the only planet, which it is not; the earth could be a flat slab and you’d still need the same number of satellites.
You launch that many you expect a lot of them fall down I suspect. Probably some go into a higher orbit and serve as spares until they decay into some more appropriate orbit.
If you have any interest in this sort of thing, get your amateur radio license and start making contacts on AO91/AO85. It's so much fun to talk to someone 500 miles away with a walkie talkie, through a satellite.
This could eventually open up other markets for SpaceX. A communication network with that density would be able to offer a better resolution than GPS and sets up SpaceX to be a key backbone service provider for autonomous flying vehicles in any form. Be that personal transports/air taxis or courier drones.
Whilst not the intended market initially and might be some design considerations that prevent that level of branching out. But certainly, something to ponder down the line.
Offering a GPS-like service would require totally different hardware. Each GPS satellite has 4 atomic clocks. The StarLink satellites will basically be optical routers and their timekeeping needs can probably be handled by a cheap clock and NTP from the ground.
Could have multiple clock sources on earth that produce the clock signals for the satellites. So a satellite could get an accurate time if it locked onto a few ground based sources.
Just with that volume and density of satellites, kinda begs some lateral thinking.
The question i'd like to have answered:
How long the sattelites actually last, considered the amount of space junk in orbit and amount of sattelites?
Do they intend to launch several sats/day?
https://www.reddit.com/r/Starlink/comments/9ud7s7/starlink_s...
A really interesting side-effect of the mass production of thousands of satellites for this constellation will be to make spacex a player in the satellite building business, bringing satellite production costs down significantly, and thus boost demand for their launch business, it will also demonstrate a high rate of launches. The two businesses can feed off each other, along with the revenue from starlink. Interesting strategy.
If their service is reliable, I would join right away. I'm in a populated area and our internet is absolutely terrible. My internet stops working at least 5 times a night. I called the provider numerous times and I plan on switching. The problem is that the competitor isn't much better. I can't wait until someone disrupts this POS industry.
Starlink I think can consider heavily leveraging a multicast or hypercast protocol considering most bandwidth usage is related to video streams. Many downlinks can accept a broadcast level packet.
How does a system link Starlink handle channel and spectrum allocation?
How long till it's possible to deploy static content to "edge" nodes in LOA? Traditional CDNs typically advertise their geo-distributed POPs on a 2D map. I want my cloud provider to live above the clouds.
What are the implication with regards to space debris? I hear it's a very real, growing problem. Will those satellites be able to withstand hits? Will they produce a lot of debris (if 2 collide for example)?
1. Space is really big so the odds of anything hitting each other are low.
2. They are launching their initial satellites in extremely low earth orbit such that atmospheric drag will cause them to decay and burn up in the atmosphere within 5 years. They are also attempting to design their satellites such that every single part of them will burn up in the atmosphere so that there is no risk of any piece hitting someone.
3. The US government is also concerned about this which is why spacex is doing their initial launch into a lower orbit that guarantees their decay into the atmosphere. Their future launches into higher orbits with longer decays will have extra considerations for such problem and thus will be evaluated by the US government individually so I would not be too worried.
They probably won't be able to withstand hits. However they have the ability to maneuver if necessary, and even if there's no maneuvering capability each one should deorbit on its own in less than a decade.
Probably the biggest concern (and this is still a very small concern!) is debris making it back to earth without burning up. The SpaceX FCC applications list some parts of the satellites that won't necessarily burn up on reentry, and some of them are large enough to ruin your day. That said, the surface of the Earth is really really big and unless something goes wrong with a satellite they'll intentionally deorbit it over the ocean so no one gets hit by space junk.
For some reasons, I think underwater transoceanic cables are much more reliable for high speed internet that satellite based internet connectivity, for now at least.
Does anyone have more details about the ground transceiver? How large will it be? What are the power requirements? How much view of the sky does it need?
The individual satellites might degrade relatively quickly, but a collision cascade could make the system unfeasible for years at a time and a certain percentage of the garbage would be kicked into higher orbits.
5G is going to kill any prospects this internet service will have in big cities within the next 5 or so years. That leaves the rural and less served areas. Can the service be cheap enough without subsidies when a big chunk of the population won't be using it?
10 years ago this would have been a great business. I suspect the business will end up being a place to sink money for Space X.
A lot of area with few customers. Will this tech truly work well? I recall using a satellite dish for access to more TV channels years ago was never quite reliable enough to be enjoyable. One storm or decent cloud cover and it was out.
This feels like another of Musk's ideas that's like, "give me a ton of money and I'll make this happen, and it only works if I can launch 100 satellites which will cost a few trillion"
How many of these have panned out? When has Musk made a profit? Will investors do due diligence this time, or just throw money at him because they perceive him as successful, despite the fact that his only profit came from a lucky website sale just before the dot com bubble burst?
I guess banks will pump this so they can get the business, and the general economy will be left to absorb the blow when this fails to meet expectations, like the rest of Musk's promises.
People that are a lot smarter and more educated in this subject matter than myself have looked this idea over (at least I hope so). And based on my level of understanding, the phased array antennas should be able to dynamically adapt to interference similar to how MIMO antennas work on wifi routers (the ones that have 2 - 4 antennas on them). At least is seems like a plausible enough idea that multiple other companies are going to be attempting the same thing.
The legg up that Spacex has is potentially very low cost launches on reused rockets. But I have a strong feeling that the major cost savings will only appear if and when BFR is ready (and if it does what is claimed).
Musk continues to promise more and deliver less. In my opinion, the fact that he's never delivered a profitable company disqualifies him from leading any major venture.
> People that are a lot smarter and more educated in this subject matter than myself have looked this idea over (at least I hope so)
This was often said of companies before the dot-com bust, and very often said of Enron. Everyone thought someone else before them had done due diligence. Now that the economy has been doing well for awhile, it's worth taking another look at ideas put forth as "it can't fail".
It seems you're attacking Musk as a person more than the idea. SpaceX is doing undeniably well, who you can attribute that to is up for debate, but my point is you should be critiquing the idea, not the man.
How about hope for the best and if you don't believe in them, then don't invest?
Imo it's a really good idea, and I'm glad someone is trying to solve the broadband issue in rural America, because there's a serious one. I live out here, you're out of touch if you don't think there's a market.
To turn this idea on its head...maybe SpaceX will be able to compete with Verizon/AT&T etc. by providing a global Internet service that also has some way of connecting to phones. I'm imagining having an Internet and cell phone plan in one, all powered by Starlink, with no roaming or other B.S. to deal with.
I remember Robert Pera, founder of Ubiquiti Networks, poking fun at Facebook for floating [pun intended] the idea of a giant hot air balloon to provide internet access while pointing out that Ubiquiti is already bringing high speed internet to remote places all over the world. I agree - skip the satellites just buy some some Ubiquiti gear.
And in my area a WISP would have a hard time getting it's upstream bandwidth because of no nearby large cities and therefore no high-speed fiber for a good distance.
The economics of megacities, 5G and fiber strongly disfavor Starlink for the world's richest urban populations. They will have a difficult time finding enough paying customers in the barren spaces of the world.
How does this work when things need to be launched into space? I get that 4,400 spread out over such a large area makes them minuscule but it's still something.
They are tracked and avoided, just like all the other satellites already up there. Low earth orbit is a large place, you could increase that number by many orders of magnitude before you'd have to start worrying.
if anyone here thinks this stuff is super cool and wants to figure out how to solve internet for the public, by making it as cheap and as fast as possible, while private, please shoot me a note at james@communityphone.org (it's my life)
EDIT: I was wrong here to criticize the latency since SpaceX's implementation will attack the problem completely differently than traditional satellite internet which has has latency numbers measured in hundreds of milliseconds.
The latency numbers due to the laws of physics through space are lower than the latency numbers due to the laws of physics through fiber when talking about reasonable distances (e.g. new york to london stock exchanges).
Light travels faster in space than fiber. SpaceX's satellites (unlike existing constellations) are low enough that that benefit makes up for the small of extra distance.
To expand on this further, current "satellite internet" offerings are through the use of geostationary satellites 22,236 mi above the equator. The latency to the satellite and back to earth, plus whatever the latency is to get to wherever you are actually trying to go, is significant.
In contrast, the offering that SpaceX has just gotten approval for would use satellites that are about 342 mi above, and the network of satellites would be used to route the connection to a hop close to the destination.
The result of the above is latencies that are actually lower than even a direct fiber connection if the haul is long enough, because connections across Starlink would be at the speed of light (minus the amount of time it takes to process packets at each hop), and the speed at which data is transferred over fiber is some fraction of the speed of light.
Most satellite internet deployments are in geostationary orbit (at 35,786km above the earth), which puts ground-to-satellite latency in the hundreds of milliseconds. Starlink will operate at just 550km, puting the theoretical latency at just 1.8ms. Even if the latency is 30x the theoretical, that's still in line with the latency of copper-cable deployment.
SpaceX's satellites are going to be in low-earth orbit, on the order of hundreds of miles -- you're thinking of traditional satellite internet which is typically in geosynchronous orbit 25,000 miles away. Depending on the number of hops, latency for these new constellations should be in the low milliseconds.
Since they're flying so low, they'll need thousands of satellites to provide wide coverage (instead of one super high satellite that can see half the earth at the same time), but they should be quite high performing.
The Verge article claims 15ms latency, which honestly is really good, even if that's in addition to what you'd get if you were using a traditional internet connection.
Looking at latencies here [1], it’s not that bad. LEO orbit is under 1500 kilometers, adds a bit of lag, but may be compensated by a better route on the other end.
That's definitely true for solutions in geostationary orbit where the signal needs to traverse 36000km twice between two ground stations, adding about 0.2 seconds delay for the request and again for the response.
SpaceX is planning a constellation in low earth orbit, that is supposed to route the traffic around the globe and down to a ground station near the point where the server is. That's saving the delay from having to go through an optically dense medium (fiber, speed of light is there about 200000km/s) and taking advantage of the much higher speed of light in vacuum.
Why? (Genuinely curious if there is a reason, I'm not an expert on this)
Satellite-to-satellite connections are handled by pointing lasers at eachother. Ground-ground connections are handled by pointing lasers at eachother through a fiber. Fundamentally they seem pretty similar to me.
I wouldn't be skeptical about the bandwidth, I would be skeptical about the execution. There are existing inter-satellite links, but they are far lower bandwidth. You need much more precision and signal processing at higher bandwidths.
Last I read the Low Earth Orbit (LEO) systems will have fiber-like latency and gigabit speeds as they are ~200 mi away from Earth where Geosynchronous Earth Orbit (GEO) systems are 20K+ mi away.
Starlink latency is quite good. LEO is a lot closer than GEO (less than ~1000 km* vs 35786 km.) SpaceX actually intends to compete with terrestrial systems on latency; many important routes will have significantly lower latency than any feasible terrestrial system.
Remember, fiber isn't latency free. It isn't even speed of light. It's about 70% SOL. Radio, on the other hand, is SOL (or so close it doesn't matter.) So there is a cross over point where the latency of a LEO satellite system is actually superior despite the uplink/downlink path.
*depending on which orbital "shell" is involved. figures range from 340 km to 1200 km.