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This article seems to be trying to get to a conclusion without a lot of support. >This works out to be around $100k per satellite, more than 1000 times cheaper
by shaklee3 7y ago
This article seems to be trying to get to a conclusion without a lot of support.
>This works out to be around $100k per satellite, more than 1000 times cheaper than a conventional comsat launch
A standard comsat satellite can potentially cover 1/3 of the globe with hundreds of Gbps of bandwidth. Starlink covers a tiny area with much lower bandwidth. Strength in numbers.
> 100MB per second using advanced coding such as 4096QAM
QAM isn't used in satcom, and certainly nowhere near 4096. Why the assumption?
> Each Starlink satellite includes all the complicated electronic switching gear found linking optical fibers together
Nope. The first batch likely had a problem and won't have inter-satellite links (per the hint from shotwell)
> All up, 2500 channels each supporting 58 Gbps is a staggering quantity of data, roughly 145 Tbps
The MIT study showed simulations that was about 20x less than that, so I'm not sure where these numbers are coming from without doing a proper simulation.
The piece that was left out, and possibly the most important, is user terminal cost. It will certainly be more expensive than a GEO antenna, and you need to recover that cost from the user. So far, there have been no practical, cheap, high-performing phased array that I know of.
- mbar84 7y ago> So far, there have been no practical, cheap, high-performing phased array that I know of. Do you thing that is more due to technical limitations or more due to relatively small markets for such antenna that perhaps has not led to economies of scale?
- shaklee3 7y agoI think technology limitations. Directtv/dish would have used it already if it was cheap enough since it's easier to install.
- manicdee 7y agoThey would only have done it if an off-the-shelf solution was already available. StarLink is going global and the target price for their terminals is $USD200 or so.
- skunkpocalypse 7y ago> > All up, 2500 channels each supporting 58 Gbps > so I'm not sure where these numbers are coming from His arse, pretty much. 58gbit/sec wireless link across 330km distances!?!? If such a thing existed we'd see it used in the much-more-forgiving earthbound context first. He got that number from the toggle rate for a chip driving a pure copper PCB trace ten million times shorter than that.
- HeadsUpHigh 7y agoThe antenna cost has been confirmed to be targeting a price of 300$ per unit.
- navigatesol 7y ago>The antenna cost has been confirmed to be targeting a price of 300$ per unit. Like the Model 3 was "targeting" $35,000 before incentives.
- shaklee3 7y agoRight, so targeting is one thing, and $300 will certainly be a good price point. But we'll have to see if they hit it. Many, many others have tried and failed.
- avmich 7y agoWhat are physical limitations? With phased aperture array we have 1) individual antennas 2) individual electronics for each antenna. Which of them is expensive?
- shaklee3 7y agoTo the best of my knowledge, they can make cheap phased array antennas that have poor performance. Poor performance can cut substantially into the overall satellite capacity, so the only way to make up for that is to charge more money. Then your service is less attractive, and people won't sign up. So you really need really well performing, and inexpensive.
- rkangel 7y ago> will certainly be more expensive than a GEO antenna I don't think this is necessarily true. Iridium antenna and RF circuitry is much cheaper than GEO because it doesn't have to receive a weak signal from far away.
- shaklee3 7y agoThat's not really what drives cost in this case. That's a very small part of it, but the phased array aspect alone is expensive based on frequency, which they're using the same ones as GEO.
- manicdee 7y agoThe first batch didn’t have inter-satellite comms onboard due to the mirrors being too robust and presenting a risk of surviving reentry.