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Astranis emerges from stealth with new satellite tech for connecting the world

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Re: Astranis emerges from stealth with new satellite tech for connecting the world

#41

Post by colanderman »

paragraft wrote: post #38
colanderman wrote: post #32

Earlier quoted context omitted.

> any request from a user requires a total of 2 [sequential] round way trips (one for request, one for response) Please elaborate? This makes no sense to me. Certainly, this is not the case for terrestrial communication (request/response latency is only 2× the one-way latency).

By "one way" the OP was referring to the ground-to-satellite trip taking 110ms. So by "round way trip" they meant a packet going from client to satellite to ground station (2 x 110ms). Thus 440ms.

OH. Of course, that makes sense. Thanks!

Re: Astranis emerges from stealth with new satellite tech for connecting the world

#42

Post by mirimir »

gedmark wrote: post #6
nappy wrote: post #2

Isn't latency a major issue for connectivity with satellites in geosynchronous orbit? I'm curious what their approach is here, either technically or what customer use cases they are targeting.

The distance to GEO does add some latency due to the distance, that’s the main trade off. What we found in studying this problem for a long time was that 95% of internet traffic isn’t latency sensitive— CDN traffic, video streaming, audio streaming, file downloads, social media posts, etc. The bandwidth crunch is a huge problem to solve but we realized there is low hanging fruit here that we can go after by putting s…

That was my first question too, once I saw that you'll be using geostationary satellites. But yes, I get your argument about acceptable latency vs cost. Sometimes I use Tor via nested VPN chains, for decent anonymity, and total rtt can be hundreds of ms or more. Web browsing, chats, downloads, and even ssh sessions, are all workable. And if push to talk is acceptable, even VoIP is workable at 1-2 sec rtt.

Re: Astranis emerges from stealth with new satellite tech for connecting the world

#43

Post by walrus01 »

gedmark wrote: post #3

Hi everyone, I’m one of the cofounders of Astranis (YC W16). Thanks for taking the time to read about what we’re doing and happy answer any questions.

Satellite earth station engineer view:

I'm interested in what the total system gain, EIRP and power looks like in an Astranis spot beam from geostationary, as compared to a current-generation 4000 to 6500 kilogram geostationary satellite with Ku and Ka band spot beams.

I am optimistic but also skeptical. The size and power of the satellite will influence what the size of VSAT terminals needs to be, and also the earth stations/major teleports. The example size of the satellite shown in the URL is so much smaller than current geostationary satellites that I don't see how the Tx power from each transponder will be anywhere near the power on a much bigger, costlier satellite.

Let's say for example I have put together from industry standard components, a 3.0 meter compact cassegrain Ku-band antenna in a remote part of Nepal, with a 40W BUC and a relatively recent Comtech EF Data modem. Are you planning on selling 1:1 dedicated capacity SCPC (and MCPC) type transponder kHz on a monthly basis? Or are you planning on standardizing on your own type of VSAT hardware terminal in bulk and selling contended access only?

Where do you see your value proposition for high capacity IP trunk links as compared to an ISP buying a 2 x 1.8m dish o3b terminal, and dedicated capacity through o3b? What will your $/Mbps rate look like compared to o3b with a monthly spend of 2500 or 3500 dollars?

Re: Astranis emerges from stealth with new satellite tech for connecting the world

#44

Post by shaklee3 »

blackguardx wrote: post #25
bmcooley wrote: post #22

Earlier quoted context omitted.

And they're being dropped in favor of geosynchronous providers.

I don't know much about their market. A friend of mine works there though, and he said they are growing.

They're not. They lost American, and they're losing market share quickly.

Re: Astranis emerges from stealth with new satellite tech for connecting the world

#45

Post by walrus01 »

gedmark wrote: post #24
PaulHoule wrote: post #10

Earlier quoted context omitted.

What effect does the small size of the satellite have on the cost and complexity of the terminal? The small-aperture terminal market has been driven by GEO satellites getting bigger, a lot bigger. Yes, we can fit more satellite in a small package, and solar cells have gotten more efficient, but there are laws-of-physics issues involving the size of the antenna, power requirements, etc. that aren't going to go away. G…

Hi there, great questions. The satellites are spec'd to deliver the same power (EIRP) on the ground as traditional large GEO's, with each of our satellites having a fraction of the capacity. This is a key point-- it will take several of our satellites to do the same job as one traditional large GEO. But that's not only ok, it's much better. It means we can put up a smaller chunk of capacity as needed and not do the "…

Your first paragraph: So basically rather than a "typical" configuration which might be 24 x Ku-band transponders, 36 MHz capacity each, supported by the solar arrays and power systemon a giant 4000 kg geostationary bus.

You're putting the Tx power into the equivalent of just one or two 36 MHz Ku transponders per satellite? Fewer transponders per satellite in a tradeoff for greater Tx power in a smaller bus?

Re: Astranis emerges from stealth with new satellite tech for connecting the world

#46

Post by shaklee3 »

PaulHoule wrote: post #14
gedmark wrote: post #6

Earlier quoted context omitted.

The distance to GEO does add some latency due to the distance, that’s the main trade off. What we found in studying this problem for a long time was that 95% of internet traffic isn’t latency sensitive— CDN traffic, video streaming, audio streaming, file downloads, social media posts, etc. The bandwidth crunch is a huge problem to solve but we realized there is low hanging fruit here that we can go after by putting s…

I am skeptical of that analysis. I have worked over ssh over internet connections with satellite-class latency and I can say it is painful. (Emacs shell mode can help) You probably think that 'the web' is a high latency application. It probably should be, and maybe it was in 2000. Since then, web developers have gotten into the habit of using AJAX indiscriminately, plus they feel pressured to add features such as cus…

SSH is not a typical use case. He said 90-95% of traffic isn't latency sensitive, and yours isn't in the majority.

Re: Astranis emerges from stealth with new satellite tech for connecting the world

#47

Post by shaklee3 »

p1necone wrote: post #8
gedmark wrote: post #6

Earlier quoted context omitted.

The distance to GEO does add some latency due to the distance, that’s the main trade off. What we found in studying this problem for a long time was that 95% of internet traffic isn’t latency sensitive— CDN traffic, video streaming, audio streaming, file downloads, social media posts, etc. The bandwidth crunch is a huge problem to solve but we realized there is low hanging fruit here that we can go after by putting s…

95% of traffic != 95% of value.

You're right. It's higher. Close to 100% of the valuable traffic is not latency sensitive.

Re: Astranis emerges from stealth with new satellite tech for connecting the world

#48

Post by walrus01 »

consciouskernel wrote: post #17

There's a reason that no other company tries to use geosynchronous orbit. Stationary orbit is at a distance of 35800 km above sea level, which implies a one way latency of 110 ms based off the speed of light. Since any request from a user requires a total of 2 round way trips (one for request, one for response), the minimum latency for a request is 440 ms. Avg latency with fiber is something like 30-60 ms, so we can…

"no other company tries to use geostationary" - uhm, probably 85% of the satellite industry by gross revenue is based on geostationary platforms. Look at Intelsat, SES, Eutelsat, Asiasat, the various north american Ku, BSS and Ka band TV satellites, etc.

Re: Astranis emerges from stealth with new satellite tech for connecting the world

#49

Post by shaklee3 »

walrus01 wrote: post #43
gedmark wrote: post #3

Hi everyone, I’m one of the cofounders of Astranis (YC W16). Thanks for taking the time to read about what we’re doing and happy answer any questions.

Satellite earth station engineer view: I'm interested in what the total system gain, EIRP and power looks like in an Astranis spot beam from geostationary, as compared to a current-generation 4000 to 6500 kilogram geostationary satellite with Ku and Ka band spot beams. I am optimistic but also skeptical. The size and power of the satellite will influence what the size of VSAT terminals needs to be, and also the earth…

Is your capacity steerable?

Re: Astranis emerges from stealth with new satellite tech for connecting the world

#50

Post by brianshaler »

paragraft wrote: post #38
colanderman wrote: post #32

Earlier quoted context omitted.

> any request from a user requires a total of 2 [sequential] round way trips (one for request, one for response) Please elaborate? This makes no sense to me. Certainly, this is not the case for terrestrial communication (request/response latency is only 2× the one-way latency).

By "one way" the OP was referring to the ground-to-satellite trip taking 110ms. So by "round way trip" they meant a packet going from client to satellite to ground station (2 x 110ms). Thus 440ms.

How long until we can co-locate application services in geosynchronous orbit to cut that latency in half?
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