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.
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?
I am kind of concerned that your answers to others' questions in this thread are vague and noncommittal.
One more question. Do you intend to:
(A) lease raw transponder kHz capacity to third party end users and ISPs (eg: the ku spot beams I can get on Russian satellites covering Afghanistan and a check for $4500 USD a month,
or (b) is your business plan to operate both the satellites and the earth stations, and resell fully packaged VSAT services directly to end users?
See also: Theranos, uBeam, etc.
Hardware startups are costly and hard.
Now do it on super hard mode and build a thing that has to go 36,000+ km away, never to be seen or touched by a human, and make it super reliable.
I'm always happy to answer basic questions about what we're doing. But questions around very specific technical details, especially when it comes to things that give us a competitive advantage like our antenna design, just aren't appropriate for a public forum. Thanks for understanding.
For more detailed questions we may or may not be able to answer them via email. But certainly I'd be happy to take a look at it and if its appropriate put them in touch with the relevant member of the team. (See-- https://www.astranis.com/about/)
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.
Geosynchronous satellite spacing is determined by the ability of ground stations to resolve satellites so there is a certain number of satellites that can fly, so there is a pressure towards large high-performance satellites that can deliver the maximum capacity as opposed to launching fewer low-performance satellites. Already the high-capacity satellites have insufficient bandwidth to serve demand (otherwise people would just be getting satellite instead of asking for terrestrial internet) and I don't see how low-capacity satellites will actually help.
I see similar problem with the terminals for systems like the SpaceX constellation. To get "wireless equivalent" performance I see the ground terminal requiring some kind of electronically scanned array which would put the cost upwards of $6000.
There is a precedent for satellite services with a high-cost terminal, as back in the 1980s many people would spend about that much for an unlicensed satellite terminal to receive TV, but since that was pirate there was no subscription fee. Compare that to $100 a month for cable and that pays for itself in 5 years.
I have this funny feeling that next-gen satellite providers want to have the expensive terminal AND the expensive service -- possibly because of the "Juicero" issue that the people bankrolling them don't know what prices look like to the average customer.
I would love it if you could prove me wrong.
The high capacity satellites do have insufficient bandwidth to serve demand, on that I agree. But that's not a spectrum limitation, its a limitation on how many such large GEO's have been launched. Which is a small number because each one is so expensive. There is still plenty more spectrum we can use for GEO telecoms, and more with proper frequency re-use schemes.
The point you make about the drive to large GEO's holds true if you assume only one spacecraft will ever be in a single orbital slot. But that's not the case. There's plenty of orbital slots where multiple GEOs are co-located, and this will increasingly be the case in the future. I'd argue the drive to large satellites was more driven by various incentives and systemic issues in the industry that drove them that direction. A much longer conversation, but it's things that can all be fixed.
And to answer your last question, because our satellites are spec'd to provide the same EIRP on the ground, the ground terminals used are the same as those in use today for GEO telecoms. These terminals are all off-the-shelf and very low-cost compared to the terminals necessary for a LEO-based network.
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?
1. What bandwidth capacity are you aiming for per spacecraft?
2. Are you using commercial or rad hard parts?
3. Is there a deployable antenna that makes the spacecraft larger than 3'x3'x3'?
2. For various reasons it doesn't make sense to go into that level of detail on a public forum.
3. Yes.
If you think there is a rural/urban problem with optic fiber, you are jumping from the frying pan to the fire with LEO satellite constellations.
That's because an LEO satellite constellation has to cover the whole world (or almost all of it) to be able to cover any inhabited area at all. Thus it has to cover oceans, large roadless areas, deserts, mountains, etc. At least with optic fiber you only have to cover roads.
Note that high density areas can cause trouble on the other side -- you need to support the highest density worldwide that you support anywhere. Note that users in a place like New York City will generate noise affecting satellites 1000+ miles away, so if you don't ban people setting up accounts in dense areas, it will have to be priced so high that people with a lot of money looking for a backup connection will be priced out.
I am highly skeptical that the economics can work out for an LEO constellation.
The amount of Mbps I could push through that will be greater than if I do the same setup with a pair of 1.8m dishes. You can't know your Mbps figure for a dedicated geostationary satcom link until you know you RF link budget, system gain, and how close you can get to the Shannon limit. The same amount of kHz (same dollar spend per month) could be used at 16QAM 5/6 or at QPSK 1/2 modulations, with very different Mbps figures.