Author Topic: Starlink direct to cell (was SpaceX & T-mobile event 25 Aug 2022)  (Read 66160 times)

Online DanClemmensen

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #40 on: 08/26/2022 03:37 am »
Adding up the size of all the StarLink V2 components....the new sat looks to be very large with 5 X 5 meter cell antennas (one element I did not see or hear from Elon is just how many cell antennas will be on each StarLink V2 sats.... seems we are assuming just 1 cell antenna per V2 sat.....   need to confirm this .... could be two or more....)   plus adding in the broadband antennas, main sat body, solar arrays, lasers, .... will be large.... size of a 737?
I'm a bit weak on phased-arrary antenna theory, but I think the same physical antenna can form multiple beams simultaneously. The part that seems like black magic to me is how an ordinary cell phone can have enough power to send a usable signal to a satellite.

Offline Robotbeat

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #41 on: 08/26/2022 03:47 am »
Adding up the size of all the StarLink V2 components....the new sat looks to be very large with 5 X 5 meter cell antennas (one element I did not see or hear from Elon is just how many cell antennas will be on each StarLink V2 sats.... seems we are assuming just 1 cell antenna per V2 sat.....   need to confirm this .... could be two or more....)   plus adding in the broadband antennas, main sat body, solar arrays, lasers, .... will be large.... size of a 737?
I'm a bit weak on phased-arrary antenna theory, but I think the same physical antenna can form multiple beams simultaneously. The part that seems like black magic to me is how an ordinary cell phone can have enough power to send a usable signal to a satellite.
Antennas work both ways. A big antenna in orbit can also receive faint signals on the ground.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Online DanClemmensen

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #42 on: 08/26/2022 03:57 am »
Adding up the size of all the StarLink V2 components....the new sat looks to be very large with 5 X 5 meter cell antennas (one element I did not see or hear from Elon is just how many cell antennas will be on each StarLink V2 sats.... seems we are assuming just 1 cell antenna per V2 sat.....   need to confirm this .... could be two or more....)   plus adding in the broadband antennas, main sat body, solar arrays, lasers, .... will be large.... size of a 737?
I'm a bit weak on phased-arrary antenna theory, but I think the same physical antenna can form multiple beams simultaneously. The part that seems like black magic to me is how an ordinary cell phone can have enough power to send a usable signal to a satellite.
Antennas work both ways. A big antenna in orbit can also receive faint signals on the ground.
That's true because the big antenna has "high gain", and that is true because a bigger antenna is looking at a smaller "cell". But that in turn implies that they need lots of cells to cover the came satellite footprint.

Offline Robotbeat

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #43 on: 08/26/2022 04:00 am »
Adding up the size of all the StarLink V2 components....the new sat looks to be very large with 5 X 5 meter cell antennas (one element I did not see or hear from Elon is just how many cell antennas will be on each StarLink V2 sats.... seems we are assuming just 1 cell antenna per V2 sat.....   need to confirm this .... could be two or more....)   plus adding in the broadband antennas, main sat body, solar arrays, lasers, .... will be large.... size of a 737?
I'm a bit weak on phased-arrary antenna theory, but I think the same physical antenna can form multiple beams simultaneously. The part that seems like black magic to me is how an ordinary cell phone can have enough power to send a usable signal to a satellite.
Antennas work both ways. A big antenna in orbit can also receive faint signals on the ground.
That's true because the big antenna has "high gain", and that is true because a bigger antenna is looking at a smaller "cell". But that in turn implies that they need lots of cells to cover the came satellite footprint.
And phased arrays can look at many cells simultaneously.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Online FutureSpaceTourist

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #44 on: 08/26/2022 04:06 am »
https://arstechnica.com/science/2022/08/forget-5g-wireless-spacex-and-t-mobile-want-to-offer-zero-g-coverage/

Quote
Forget 5G wireless, SpaceX and T-Mobile want to offer Zero-G coverage
"So it's really quite a difficult technical challenge."

ERIC BERGER - 8/26/2022, 12:40 PM

BOCA CHICA, TexasóSpaceX and T-Mobile announced an ambitious plan on Thursday evening to provide ubiquitous connectivity to anyone with a cell phone from space.

The project would pair SpaceX's Starlink satellite technology with the second largest wireless carrier in the United States, T-Mobile US, and its mid-band spectrum, mobile network, and large customer base.

Edit to add:

https://twitter.com/elonmusk/status/1563016064555814914

Quote
Good summary
« Last Edit: 08/26/2022 04:16 am by FutureSpaceTourist »

Offline Robotbeat

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #45 on: 08/26/2022 04:18 am »
Another day in the Demolition Man universe, another industry that Taco Bell takes over. ;)
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline su27k

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #46 on: 08/26/2022 04:43 am »
Lot of folks bringing up AST Spacemobile being able to offer a higher bandwidth service for mobile connection. 

So how are they able to do this? Bigger satellites than SpaceX? More powerful phone handsets?  And how can they do so with an order of magnitude fewer satellites than Starlink?

In short, what is the competitive advantage they have in this space that SpaceX cannot overcome with a bit of focused effort?

Yes, AST's satellite is much bigger, production version is 450 square meters I believe (reduced from 900 square meters due to space debris concerns). But a direct comparison of antenna size is misleading since:
1. AST's orbit is higher, at 720km, while Starlink Gen2 has ~19,000 satellites at around 350km
2. Starlink has a lot more satellites, tens of thousands comparing to AST's 240 satellites

So I think any comparison of the two offerings without taking these into account is premature.

Offline soyuzu

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #47 on: 08/26/2022 05:33 am »
Lot of folks bringing up AST Spacemobile being able to offer a higher bandwidth service for mobile connection. 

So how are they able to do this? Bigger satellites than SpaceX? More powerful phone handsets?  And how can they do so with an order of magnitude fewer satellites than Starlink?

In short, what is the competitive advantage they have in this space that SpaceX cannot overcome with a bit of focused effort?

I made a small comparison

Provider Rate/cell      Antenna area  Orbit
AST       120Mbps      450m2           720km
SpaceX  4Mbps          25m2            340/550km

In short, higher orbit and significantly larger antenna, though I used to think SpaceX would be able to provide this kind of service with just 10m2 or less antenna.

Offline M.E.T.

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #48 on: 08/26/2022 07:16 am »
Lot of folks bringing up AST Spacemobile being able to offer a higher bandwidth service for mobile connection. 

So how are they able to do this? Bigger satellites than SpaceX? More powerful phone handsets?  And how can they do so with an order of magnitude fewer satellites than Starlink?

In short, what is the competitive advantage they have in this space that SpaceX cannot overcome with a bit of focused effort?

I made a small comparison

Provider Rate/cell      Antenna area  Orbit
AST       120Mbps      450m2           720km
SpaceX  4Mbps          25m2            340/550km

In short, higher orbit and significantly larger antenna, though I used to think SpaceX would be able to provide this kind of service with just 10m2 or less antenna.

Ok, but why can SpaceX not increase their antenna size over time? If there really is a trillion dollar market at stake they can surely erase that one disadvantage by the time they reach Starlink Gen 3?

Edit 1

Also thereís the small matter of having 10,000+ sats vs just 243 or thereabouts.

Edit 2

Also, are these cells the same size? Presumably the constellation with fewer sats will need to cover a much larger area per cell. Meaning a lot more people needing to be covered by that 120Mbs than by the 4Mbs?

Edit 3

Where do you get 450sqm from? The CEO of AST posted today that their satellite launching soon will have a 693sq foot size. Thatís around 75sqm.
« Last Edit: 08/26/2022 08:06 am by M.E.T. »

Offline Danderman

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #49 on: 08/26/2022 03:51 pm »
The first AST satellite is a subscale prototype.

Offline Danderman

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #50 on: 08/26/2022 04:03 pm »
Elon made a bit of a mistake in designing the V2 constellation.

Disclaimer: I am a founder of Lynk.

The mini-V2 sats launched on F9 will not support handhelds. So, to the extent that Starlink V2 goes up on F9, T-Mobile has no service.

Therefore, the later Starship enters operational status, the later T-Mobile has a viable offering.

What happens if 40% of the 2nd gen constellation is initially made up of mini V2 sats that donít support handhelds, and then the rest (full V2 sats) are launched on Starship? Does Elon replace the first 40%? Or, wait for the 3rd gen satellites?



Online gongora

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #51 on: 08/26/2022 04:19 pm »
If one shell can support the cell service then having a different shell be made up of mini-sats may not matter.  They said the initial Gen2 deployment would be three of the shells.

Online jimvela

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #52 on: 08/26/2022 04:23 pm »
Starlink are all short-lived, and continuous replacement and upgrades is already planned. 
Where is it documented what is or is not on the 'mini' Starlink V2?

I'll bet there's tremendous pressure to get the Starlink deployer version of Starship operational as soon as possible.
Not just for this opportunity, but because in retrospect hosted payloads on the anchor Starlink constellation may be an enormous revenue opportunity in its own right.  Mixing multi-national elements of defense, earth observation, telecommunication, and low-orbit satcom.  Probably plenty of things I'm too dense to think of- but likely there are already groups clamoring for the opportunity.

Very interesting development.

Offline TheRadicalModerate

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #53 on: 08/26/2022 04:45 pm »
IIRC, Sievert said that this will work "anywhere you can see the sky," which sounds like a throwaway line for complete geographic coverage, but I wonder if there's going to be an issue with trees.  Ordinarily, 5G bands don't have much trouble with that, but they also aren't trying to communicate with a base station that's 550km away.

I also noticed that Elon talked briefly about the challenges of adjusting for doppler shift, but he didn't say anything (that I heard) about getting synchronous transmission ironed out.  Getting the bird to agree on the timebase with the UT's sounds like a pretty ghastly problem. 

As I remember, 4G+ can work either with a pre-registered slot for high-bandwidth comms, or with an ad-hoc slot that's requested on demand.  I assume that all of the Starlink stuff will be ad-hoc?  Otherwise, spectrum efficiency will be terrible.
« Last Edit: 08/26/2022 04:54 pm by TheRadicalModerate »

Offline TheRadicalModerate

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #54 on: 08/26/2022 04:54 pm »
If one shell can support the cell service then having a different shell be made up of mini-sats may not matter.  They said the initial Gen2 deployment would be three of the shells.

I'm yet again confused by whether there's any difference between "v2" and "Gen2".  V2 is a satellite; Gen2 is a yet-to-be-licensed deployment. 

Are v2 birds only to be used by the Gen2 deployment?  Or will we see v2 birds in the Gen1 deployments for the two already-granted licenses?

I guess I should also ask the question whether this mini-v2 form factor might replace v1.5 for the current deployments?  That would limit the number of actively manufactured versions to two.  If they have v1.5, mini-v2, and maxi-v2 all running, they need three different lines.

Offline Robotbeat

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #55 on: 08/26/2022 05:21 pm »
Elon made a bit of a mistake in designing the V2 constellation.

Disclaimer: I am a founder of Lynk.

The mini-V2 sats launched on F9 will not support handhelds. So, to the extent that Starlink V2 goes up on F9, T-Mobile has no service.

Therefore, the later Starship enters operational status, the later T-Mobile has a viable offering.

What happens if 40% of the 2nd gen constellation is initially made up of mini V2 sats that donít support handhelds, and then the rest (full V2 sats) are launched on Starship? Does Elon replace the first 40%? Or, wait for the 3rd gen satellites?
Are we certain that mini-V2 canít support handsets at all, even in a reduced-capacity?
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline kevin-rf

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #56 on: 08/26/2022 05:28 pm »
Starlink are all short-lived, and continuous replacement and upgrades is already planned. 
Where is it documented what is or is not on the 'mini' Starlink V2?

Musk said during the event that F9 launched "Mini" V2's would not carry the cellular package.

It also looks like, and I may have misread this that initial phase II satellites will not be inclined more than 53 degrees. So cellular coverage of Alaska and northern Canada may come at a much later date. That said, they really have not started launching phase 1 shell 2 satellites... (Maybe they could be Starship V2's, we will not know until they resume building shell 2)   
« Last Edit: 08/26/2022 05:31 pm by kevin-rf »
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Online TrevorMonty

Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #57 on: 08/26/2022 06:30 pm »


Lot of folks bringing up AST Spacemobile being able to offer a higher bandwidth service for mobile connection. 

So how are they able to do this? Bigger satellites than SpaceX? More powerful phone handsets?  And how can they do so with an order of magnitude fewer satellites than Starlink?

In short, what is the competitive advantage they have in this space that SpaceX cannot overcome with a bit of focused effort?

I made a small comparison

Provider Rate/cell      Antenna area  Orbit
AST       120Mbps      450m2           720km
SpaceX  4Mbps          25m2            340/550km

In short, higher orbit and significantly larger antenna, though I used to think SpaceX would be able to provide this kind of service with just 10m2 or less antenna.

This is how I see it working.
Cellphone users will still connect to these space services via there existing cellphone provider, the company who owns your SIM eg Vodaphone. You pay Vodaphone for additional coverage you want in remote areas eg texting, voice, low-speed data, high-speed data(120Mbps). Vodaphone use which ever company they have partnership with.

It won't be any different from global roaming where cellphone users don't know and care who's cell tower their calls go through. That's between their provider eg Vodafone and local cell company.

As with roaming it's likely something you turn on or off depending on your needs and pay accordingly. Emergency 911 calls and texts are likely to be exception.

Offline EL_DIABLO

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #58 on: 08/26/2022 06:40 pm »
Is there a thread with more in depth discussion on ASTS? I just watched some of their videos and it seems to be too good to be true, getting distinct SPAC scam vibes a la Nikola Motors.
« Last Edit: 08/26/2022 06:43 pm by EL_DIABLO »

Offline gemmy0I

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Re: SpaceX and T-mobile event 25 Aug 2022
« Reply #59 on: 08/26/2022 08:21 pm »
Itís interesting as SpaceX seem to be making a notable investment to enable this and yet T-mobile plan to add for free to their most common plans. So must limit amount T-mobile are prepared to pay SpaceX. Of course Elon is no stranger to big bets, so probably looking at pay off longer-term.

T-Mobile could also be using this as a "loss leader" of sorts to try and get more people on their plans. I imagine this deal was good enough money for SpaceX but relative pocket change for the telecom industry.
☝ This. As someone who lives in a rural (U.S.) area where cell signals are spotty at best, dead zones are a major - to the point of dominant - factor in how families like mine choose their cell carrier. We're on T-Mobile right now for exactly this reason. They bought heavily into the mid-band (ex-analog TV) frequency ranges for their 4G LTE and 5G expansion - unlike most other U.S. carriers - which is often counted against them as a negative for urban 5G (as it doesn't allow them to reach the ultra-high theoretical speeds that other carriers' mm-wave deployments can get over city-block-level distances), but it is the only way to get service at all in rural areas.

(Incidentally, T-M's lack of mm-wave spectra was one of the big reasons they merged with Sprint, since their respective strengths and weaknesses in spectrum allotments neatly complemented each other.)

The irony of the steady march forward in cellular technology generations has been that the push to higher and higher bands has made service much better for urban customers but largely killed rural service. Back in the days of analog 1G cell phones with their super-large cells, friends from the city would come out to visit us in our rural area and be amazed at how great a signal they got, as rural hills were the prime places to put 1G towers. Ironically, by the time we started getting cell phones of our own, things were shifting from 2G to 3G to 4G, and our service at home went from weak to piddling to near-nonexistent. We only recent got back to having any service at all when T-Mobile started adding the ex-analog-TV bands to their 4G LTE service, and their subsequent 5G rollout has strengthened that coverage from spotty (only worked in certain parts of our house) to weak-but-consistent.

We were tempted to switch to Spectrum Mobile (which uses Verizon's network) a couple years back because they were offering a good bundle deal with our hardline Internet service, but that ended up being a no-go because Verizon has no meaningful coverage on our hill these days, and going forward their 5G plans are mostly in the urban-focused higher spectra. We decided to stay with T-Mobile primarily because they are the only carrier heavily investing in rural coverage.

So, this Starlink partnership will absolutely be a huge win for T-Mobile simply as a way to clinch the deal with customers for whom rural coverage is paramount. My first thought when watching the announcement video last night was "well, I guess we know who we're staying with going forward!" A lot of customers are going to be making similar decisions based on this, especially once the service is widely rolled out and word of mouth starts spreading to non-experts.

Although we now just barely get a consistent 5G signal from T-Mobile at our house, most of the country roads we drive on in our area are constantly popping in and out of dead zones. We usually don't receive text messages until we reach our destination. The Starlink partnership has the potential to be an absolute game-changer for that. Even just having basic texting capability "everywhere" will work wonders for peace of mind about emergency scenarios.

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