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SpaceX launches another 60 Starlink satellites while setting two reuse records

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Re: SpaceX launches another 60 Starlink satellites while setting two reuse records

#141

Post by soulofmischief »

phreeza wrote: post #107
soulofmischief wrote: post #97

Earlier quoted context omitted.

Soon (a decade or two) every major corporation and organization will have a manned station of their own.

To do what?

I figure it'll be a cascading effect, once the price drops below a certain threshold, any horizontal organization is going to jump on board once they see others doing the same. Some for research purposes, some for economic, some to act as watchdogs, but most of them propelled by the motivation of being among the first to market. The window of opportunity to launch a station with ease might vanish as near-Earth space inevitably becomes coated in a thick spiderweb of legislation. Also, to evade taxes.

Re: SpaceX launches another 60 Starlink satellites while setting two reuse records

#142

Post by carlosdp »

mdorazio wrote: post #51
carlosdp wrote: post #48

Earlier quoted context omitted.

Google dipped out of rolling their own fiber because all the other ISPs started doing it, so there was no need anymore.

Pretty sure Google dipped out of rolling their own fiber because dealing with city councils, pole sharing nonsense, lobbying from incumbent ISPs, and customer service overhead was a huge pain in the ass that doesn't fit with their current operating model.

Sure, that too

Re: SpaceX launches another 60 Starlink satellites while setting two reuse records

#143

Post by jandrese »

_flgt wrote: post #138
wmf wrote: post #137

Earlier quoted context omitted.

Tell that to the HFT people.

Is this some fixed point-to-point line of sight terrestrial microwave link? I'd believe that could do it. Do HFT people ever communicate with spacecraft though?

No, the point of the HFT links was to make the most direct shot possible so they could beat the packets traveling via fiber. Going up to space would defeat the purpose.

Re: SpaceX launches another 60 Starlink satellites while setting two reuse records

#144

Post by jandrese »

paulsutter wrote: post #73
jandrese wrote: post #64

Earlier quoted context omitted.

Except that the more remote your location the further you likely are from the nearest ground station, which means more hops through the satellite network before you get back down to the ground, higher latency, and reduced total throughput of the system. The system Starlink is trying to beat is BGAN and regional Ku/Ka providers. If you're expecting them to beat the pants off of your terrestrial wired service you're pr…

You want to downlink near the server, not near the client. Packets will move 40% faster through vacuum than through fiber.

The more traffic routes through the satellites vs. the ground the more you'll be competing for that limited sat-to-sat bandwidth and the more queuing delays you will suffer. You want to get the bits off of the birds and onto the ground ASAP if you want to maintain consistent latency figures.

This was a big problem with Iridium. With only one ground station available your latency figures were all over the place thanks to the complicated routing that every packet had to go through.

Re: SpaceX launches another 60 Starlink satellites while setting two reuse records

#145

Post by _flgt »

paulsutter wrote: post #139
_flgt wrote: post #135

Earlier quoted context omitted.

I haven't seen a link budget. Do you have a link for one about the "likely error rates"? My guess is Starlink is going to need FEC for Doppler effects and multipath in urban environments. Maybe they will be able to overcome multipath with modulation. But Doppler shift will be significant with LEO. The latest 802.11n standards have been increasing physical layer frame sizes, not decreasing them. I don't know of any mo…

Elon talks about 20ms or 10ms, not 100. He wouldn’t be wrong by a factor of 10. You’re really just speculating based on some non IP based overarchitected mil spec monstrosity you’ve seen before https://mobile.twitter.com/elonmusk/status/11329039145865297... Besides we’re talking about the latency of the satellite to satellite links, not the downlink (since that’s the difference between using a downlink close to the c…

Yeah, I'm speculating and so are you. Your citation is an Elon tweet.

I'm not talking satellite to satellite latency, I'm talking total latency end-to-end. I'm also not saying the system will be 100 ms, just that it takes significant engineering effort so latency doesn't get out of control. IMHO, it's a fundamentally much harder problem than existing transatlantic links, despite the greater signal speed in a vacuum. I'm skeptical of what the latency will be. You disagree and that's fine.

Maybe we'll see an actual measurement soon enough. The competition can do 60 ms round-trip to NYC to London.

Re: SpaceX launches another 60 Starlink satellites while setting two reuse records

#146

Post by sneak »

mastax wrote: post #109
Paul-ish wrote: post #92

Earlier quoted context omitted.

Netflix claims an UHD stream is 25 Mbps. This is probably the most demanding use case for your average consumer, but it may not be a rare use case in the near future. Each satellite can support 800 UHD streams. That doesn't seem sufficient if each satellite covers a large geographic area. This suggests to me a low data cap and/or rate, perhaps comparable to DSL.

12,000 satellites is the current FCC approved launch figures, I believe. 20Gbps per satellite but I don't know if that's full duplex or how much is divided between terminal/gateway, so lets divide that in half. For simplicity let's say they only sell consumer-grade 100Mbps connections, which are oversubscribed 100x as is typical. Divide the possible number of customers by 3 to account for uneven geographic distributi…

I think your simple calculation assumes relatively even geographical subscriber distribution, which absolutely is not the case. Just rough estimating, assuming every other figure is approximately correct, you’ll probably have to cut that by 50-75% based on people’s natural tendency to live near other people.

A few HFT customers will probably finance the whole thing, tbh.

Re: SpaceX launches another 60 Starlink satellites while setting two reuse records

#147

Post by akira2501 »

gfodor wrote: post #98
randyrand wrote: post #33

Earlier quoted context omitted.

Keep in mind, the entire Starlink array will only be able to handle like ~1% of global consumer internet traffic. They're only a handful of gbps downlink each. ~10gbps downlink.

Starlink apparently won't be a fixed concept. 5 year sat lifecycle means its likely we'll see rapid year-over-year turnover and hence macro-level iteration on the specs and design.

RF and the Atmosphere being what they are and the non-variable parts of this equation mean there are significant real physical and abstract legal limits for any project attempting to put "bandwidth in orbit."

Re: SpaceX launches another 60 Starlink satellites while setting two reuse records

#148

Post by paulsutter »

_flgt wrote: post #145
paulsutter wrote: post #139

Earlier quoted context omitted.

Elon talks about 20ms or 10ms, not 100. He wouldn’t be wrong by a factor of 10. You’re really just speculating based on some non IP based overarchitected mil spec monstrosity you’ve seen before https://mobile.twitter.com/elonmusk/status/11329039145865297... Besides we’re talking about the latency of the satellite to satellite links, not the downlink (since that’s the difference between using a downlink close to the c…

Yeah, I'm speculating and so are you. Your citation is an Elon tweet. I'm not talking satellite to satellite latency, I'm talking total latency end-to-end. I'm also not saying the system will be 100 ms, just that it takes significant engineering effort so latency doesn't get out of control. IMHO, it's a fundamentally much harder problem than existing transatlantic links, despite the greater signal speed in a vacuum.…

I think you’re suggesting an /extra/ 100ms in addition to speed of light time, which is to speculate that they’ll do it in a way that’s needlessly crappy.

I’m speculating they’re smart guys working hard to keep latency low, and that routing will be a more challenging latency issue, while serialization should be minor.

But we’ll see and I agree we’re both speculating

Re: SpaceX launches another 60 Starlink satellites while setting two reuse records

#149

Post by akira2501 »

bane wrote: post #57
callesgg wrote: post #9

One off the satellites where apparently already dead and would not respond to commands when they got it mounted on the rocket. But they launched it anyway.

I've been having this hard to articulate notion that humanity hasn't really begun to fathom the changes that will come with "cheap" launch vehicles. We have better than half a century where space launch was so expensive, and so rare, that this had an impact on the payloads themselves. Perversely it caused the payloads to become so highly engineered (for a variety of reasons) that they also became ultra-expensive in-l…

> billions upon billions of dollars to basically put a large 1 MP sensor at the end of a tube with a digital radio for communications.

That's such a gross over-simplification of what the Hubble platform is and what it is capable of that it annoys me.

First, there are _six_ scientific sensor packages on the Hubble craft. These have been swapped out and upgraded several times during its life with a process that allowed us to bring the failed instruments back to surface and study them.

Second, it's not just scientific instruments.. the Hubble is one of the few satellites to have a fine guidance system, that allows it to lock onto and then _track_ with extreme precision exceptionally distant objects. The newer JWST is the only other telescope with similar capabilities.

This system has also been upgraded during the several servicing missions that were a planned part of the entire mission, which is another reason the initial costs were so high. This is an exceptionally advanced program to launch one of the most advanced scientific instruments we created up to that point.

Finally, I think it's also worth pointing out that Hubble was launched into orbit over 29 years ago and it's still working.. which is incredibly impressive considering it has to transit between Earth's shadow and direct sunlight every 47 minutes.

This thing is as _far_ from "a 1MP sensor at the end of a can attached to a radio" as you can possibly get. By the way, we could have made it larger.. but congress wanted to keep the price under $100 million. (Or about $201 million in Today's dollars).

> We could launch not only an equivalent, but technologically improving payload every month?

If all you're doing is making phone calls and routing packets, sure. If you're trying to do legitimate astrophysical science it seems almost an entirely worthless attribute.

> We have no idea what's about to happen in the next decade.

I think your reasoning is exactly backwards. We only launched highly specific and purpose built scientific instruments because it was the only thing _worth_ doing with our previous limited and highly government subsidized launch activities.

There was simply no way to commercialize those launches, and now that we entering an era where you easily can see long term value in them, you're simply going to see typical commercial activities and value realization behavior when they utilize this destination. It's absurdly predictable.

Re: SpaceX launches another 60 Starlink satellites while setting two reuse records

#150

Post by dantheman »

organsnyder wrote: post #105
sp332 wrote: post #80

Earlier quoted context omitted.

Also, they weren't very good at it. https://arstechnica.com/information-technology/2019/02/googl... "When you're walking around the neighborhood, [the lines are] popping up out of the road all over the place," resident Larry Coomes said at the time. "People are tripping over it." ... "AT&T has been using various forms of shallow trenching since 2009 and hasn't seen similar issues."

Like so many other examples, a new entrant realized that the industry wasn't as simple as they thought it was.

It was an experiment to see if a new technique would drastically lower costs - it didn't. We should be encouraging people to try new things.
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