portillo

7 ms·

1.
by portillo 5y ago
This is exactly right! I think that 5M is a high number (at least with the current number of satellites and their architecture), specially if they do not apply data caps. I would say that 1M customers in the US is a more reasonable figure.
2.
by portillo 5y ago
There are multiple pictures of OneWeb´s assembly line in their website, https://onewebsatellites.com/factory/ , including pseudo-blueprints: https://bit.ly/32QSDBS Still far from what you would expect
3.
by portillo 5y ago
A satellite dish does not transmit any information to the satellite. Satellite TV is a pure broadcast system in the forward direction. Moreover, comparing a parabolic receiver with a phased array is quite unfair. The amount and complexity o
4.
by portillo 5y ago
Reminds me of OpenLASE: - https://github.com/marcan/openlase - https://www.youtube.com/watch?v=hoWCNKhZCbk
5.
by portillo 6y ago
You can get 24/7 connectivity to LEO right now (and 25 years ago too) using TDRSS. The system costs a fraction of what Starlink will cost, as you only need 3 GEO satellites.
6.
by portillo 6y ago
The current satellites do not have crosslinks, and in any case, in their FCC filings SpaceX talks about optical crosslinks, not RF.
7.
by portillo 6y ago
I agree, this was the real reason why the project failed. Moreover, it was not clear at all that fractionation would bring any lifecycle costs savings, neither that any of the alleged extra flexibility (and maneuverability, resiliency, main
8.
by portillo 6y ago
Sure, operated manually by a bunch of people with PhDs.
9.
by portillo 6y ago
I think so too. In addition, they seem to have regenerative payloads on-board (otherwise I don't get how they get ~20Gbps/sat with a single Ka-band antenna), so they need to do full decoding + encoding on the satellite. Not sure h
10.
by portillo 6y ago
Hi Mark, Thanks for your reply. I agree with you, using user-terminals is extremely challenging, especially from a link-budget perspective. You cannot pump enough data to make it worth it. For the gateways, my main concern is that the Ka-ba
11.
by portillo 6y ago
These analyses are quite optimistic as they only consider propagation delay. Moreover, the idea of using user-terminals/gateways as ground-relays to bounce signals up-and-down is quite impractical, since you would be greatly reducing t
12.
by portillo 6y ago
That is not the round trip time, it's the one-way delay. Also, processing time can be significant in satellite networks. Finally, given the current architecture of SpaceX without crosslinks, the total RTT will be ~30 ms + processing ti
13.
by portillo 7y ago
It will not work. Their use case is low data rate applications. It's one of those case where you pick 2 among high number of users, high bandwidth, and low gain user terminals.
14.
by portillo 7y ago
> to a self-described expert, who unfortunately didn't provide a ton of context), Are you questioning the expertise of Tim Farrar? If that is the case, you couldn't be more wrong. Check his blog and you will see he has been doi
15.
An analysis of Starlink economical feasibility(tmfassociates.com)
2 points by portillo 7y ago|0 comments
16.
by portillo 7y ago
In their original FCC filing, they were estimating 386 kg per satellite. The ones launched in May were 227 kg each, and those last month 260 kg (they added the Ka-band antennas). I am not sure how much heavier will the satellites be when th
17.
by portillo 7y ago
I am the author of the slides/paper. The analysis was done with the best data available at the time, but I am interested in knowing what parameters you think are off / have changed substantially since then. I can say that the mass
18.
by portillo 7y ago
NSR has some public estimates here: https://www.nsr.com/leo-survival-of-the-fittestor-the-smarte... NSR estimates for SpaceX are higher than what SpaceX claims (Gwynne Shotwell just claimed some Morgan Stanley estimates of
19.
by portillo 7y ago
It will only have lower latency when they have the inter-satellite links. Until then, they will have the latency of fiber PLUS the RTT from the user terminal - satellite - gateway path.
20.
by portillo 7y ago
I would bet that there will be no more than 1,200 (if they raise the money needed to launch and manufacture that many). And I would also bet that even in an 8 year time-horizon, they will not launch 12,000 satellites for Starlink because si
21.
by portillo 7y ago
This is, in my opinion, kind of a myth. In the markets where the average revenue per user is high (Europe, USA, Canada, Australia) there is already (or there will be very shortly when Viasat3 is fully launched) high-speed reliable Internet
22.
by portillo 7y ago
It was ordered by the "Juzgado Central de Instrucción número 6" of the "Audiencia Nacional" which is presided by Manuel Maria Garcia-Castellon. The police cannot request taking-down a website without a judicial order.
23.
by portillo 7y ago
> So from far away, I would question the neutrality of the Centre d'Studis d'Opinió. They are the "Department of Statistics" of Catalonia, and they are controlled by the local government (pro-independence), so i am no
24.
by portillo 7y ago
I hope that ends up happening, it will be a bigger innovation than all these constellations!! I don't think it will happen in the next 3 years though. I think that most of the manufacturers are focusing on the high-end market, and firs
25.
by portillo 7y ago
My PhD research is on how to use space and aerial networks to serve the unconnected and undeserved. I have been studying these networks (and things like Google's loon, mmwave, etc) for the last 4 years. I have simulated these networks
26.
by portillo 7y ago
Well, you are saying that you have a fixed bitrate per beam to divide among all the users in the area. The bigger the area the more users. And once you reach saturation, that's it. Also, if there is a very populate city inside the beam
27.
by portillo 7y ago
I also like Tim's idea here: https://twitter.com/TMFAssociates/status/1183436364974419968
28.
by portillo 7y ago
You are right, maybe I should have said where the sub-100$/kg comes from. In the first Starlink launch, with 60 satellites of ~230 kg each, the cost of launch was ~$30M (considering that the "retail price" of a Falcon 9 launc
29.
by portillo 7y ago
You could provide home broadband using a wireless, mobile-network like system if you wanted to. It is not happening because it's very difficult to do that with the spectrum allocated for mobile services. A network of towers can provide
30.
by portillo 7y ago
For the source, see [1]. "The coverage gap– those living outside of areas covered by mobile broadband networks4–continues to decrease below the 1 billion threshold and now stands at 750 million people. Since 2014 the gap has more than

More ›