
A new firm says it can link satellites to ordinary smartphones - sohkamyung
https://www.economist.com/science-and-technology/2020/03/07/a-new-firm-says-it-can-link-satellites-to-ordinary-smartphones
======
londons_explore
Every time you see a claim like this, remember the Shannon–Hartley theorem[1].

If you want to get a decent bandwidth in aggregate for your mobile network,
you're going to need to consider:

* Maximize transmit Power: which is hard because phones are battery powered, and power is limited by law. Satellites are also battery powered.

* Maximize bandwidth: Also limited by rules and regulations.

* Maximize Directionality: If you have physically large antennas, you can direct your transmit power towards the receiver to make best use of it.

* Minimize Distance: Received signal power goes down the the square of he distance. Double the distance, and you get one quarter of the bandwidth, all other things being the same.

This proposal uses tiny existing antennas in phones, which means it must be
making other tradeoffs. My guess is it seriously sacrifices the total
throughput.

[1]:
[https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theore...](https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem)

~~~
amelius
> Satellites are also battery powered.

I thought they have solar panels.

Also, don't phones and satellites use small antenna arrays to direct power in
a certain direction?

~~~
moopling
The batteries are powered by solar panels. In either case the same arguments
apply - space is notoriously low power.

Phones can't use directional antennas, otherwise you'd have to point them at
radio towers. Using phased array antennas in which directionality is software
controlled, there's a trade off between size of antenna and how much you can
focus the beam - it wouldn't work in a phone (and would be too expensive
anyway).

~~~
Robotbeat
Space is notoriously expensive... until it isn’t. Launch costs have reduced by
an order of magnitude and may reduce by another as full reuse becomes
feasible. All of a sudden, you’re using near-commodity solar cells with a
higher capacity factor (and more consistency) than on the ground. Power is
thus not so expensive any more.

Industry rules of thumb are only good if the industry is stagnant.

~~~
new_realist
And yet SpaceX still struggles to find launch volume.

~~~
gpm
I'm not sure what you're trying to say here. That SpaceX's launch business
struggles to find enough customers, or that SpaceX's satellite business
struggles to get enough launches to orbit?

Ironically both are sort of true... and I'm not sure how either of them
respond to the post you replied to.

SpaceX has been struggling to get enough external customers recently, the
launch market has been in a bit of a slump and external customers haven't yet
substantially responded to the lowering launch costs.

SpaceX's Starlink constellation needs a huge number of launches, to the point
where it seems at best barely feasible in both cost and launch volume to
launch it on current rockets. They hope to fix this with their in-development
starship rocket which should be able to launch an order of magnitude more
satellites at a time (400 vs 60), at an order of magnitude less cost as a
result of full re-usability and easier construction of the rocket.

------
supernova87a
Having been an amateur watcher of the last 20 years of satellite ventures, I
find that going into the business of satellite internet/voice is only slightly
less profit making than starting an airline.

There's something exciting/sexy about launching satellites, which may be why
people so easily dump money into it. But from Iridium, Globalstar, Terrestar
(anyone remember that one? Seem to be quite relevant here), I don't think
anyone attempting to reach a broad consumer market has ever made big money, or
even survived long term. For some reason, the customer growth factors in their
profit models (at the offered service pricing) are always wrong by a few
hundred %, yet they keep being believed. Maybe it's because VCs think that
their desire for a strong signal on their yacht correspond's to the average
person's willingness to pay.

Maybe ventures like Elon Musk's may break the mold with a different cost
structure (while littering our outer space), but for a run of the mill
satellite, odds are you're going to fail quite soon.

The best way to make money related to satellites is to be the entity that buys
the initial satellite company after it goes bankrupt.

~~~
state_less
Your argument would be better if you had numbers to back it up. What is the
capital costs for the project? How much does the capital cost per year? How
many customers do you expect they will have?

If Starlink is a 5 or 10 billion dollar project, that's $250-500M to service
the capital. At $80 a month for service, you'd need ~500,000 subscribers to
cover that cost. I think Starlink can get at least 500k subscribers and keep
customers happy with bandwidth and latency.

Anyway, that's just napkin math, but might serve as a better foundation for
thinking how likely the business model is to succeed.

[https://en.wikipedia.org/wiki/Starlink](https://en.wikipedia.org/wiki/Starlink)

------
exar0815
As far as I can gleam from this report, they want to revitalize the old "bent
pipe" model of satellite communication, where the sat only acts as a repeater
. I am still very wary of it being feasible. While the track of BS->MS is
feasible, albeit with a high transmission loss, i cannot fathom how they want
to receive the <1W signal of the MS. Conventional way to pick up a signal
below the noise level would be decorrelation, and while 3G/4G work on that
principle, there would have to be additional information exchange between BS
and Satellite. Additionally, for that to work the SATs have to be in LEO, and
as they describe them as "massive"(most probably the high-gain antennas),
there then will be massive atmospheric drag, requiring either frequent
reboosting or replacing.

~~~
bucket2015
What's "BS" and "MS" here?

~~~
imglorp
Mobile Station and Base Station. They're used widely in the GSM specs but more
general now.

[https://www.ques10.com/p/5206/gsm-network-
architecture-1/](https://www.ques10.com/p/5206/gsm-network-architecture-1/)

------
nabla9
After Looking at the company FAQ all I can say: What the hell?

\---

[https://ast-science.com/spacemobile/faqs/](https://ast-
science.com/spacemobile/faqs/)

* How does the technology work?

The technology is highly proprietary, and exactly how it works cannot be
disclosed. We can say that our engineers and space scientists have designed an
entirely new form factor and deployment method that significantly reduce the
time and costs associated with manufacturing, launching and operating
satellites. Our team also has worked – and continues to work – closely with
mobile network operators to ensure compatibility with today’s wireless
networks, including 5G.

* Do users need a satellite phone or special antenna?

No, SpaceMobile will be the first and only space-based network to work with
standard mobile phones. No separate or specialized satellite hardware is
required.

* Do you need clear line of sight to SpaceMobile satellites for connectivity?

No, our proprietary technology enables access to SpaceMobile from any location
— even inside — regardless of visibility to the satellites on orbit.

~~~
notyourday
Nah, it is just a stock pump and dump scheme for the gullible investors.

------
lgats
Experimental FCC licenses for AST & Science:

[https://fcc.report/ELS/AST-Science/0908-EX-
ST-2019](https://fcc.report/ELS/AST-Science/0908-EX-ST-2019)

2207.87500000-2208.52500000 MHz FX 10.000000 W

[https://fcc.report/ELS/AST-Science-LLC/0047-EX-
CN-2019](https://fcc.report/ELS/AST-Science-LLC/0047-EX-CN-2019)

2033.37500000-2033.62500000 MHz FX 10.000000 W 7100.000000 W P 0.00010000 %
250KG1W GMSK

2033.50000000- MHz FX 10.000000 W 7100.000000 W P 0.00010000 % 250KG1W GMSK

2207.87500000-2208.52500000 MHz FX 10.000000 W 7100.000000 W P 0.00010000 %
500KG1W GMSK

[https://fcc.report/ELS/AST-Science-LLC/0884-EX-
CN-2018](https://fcc.report/ELS/AST-Science-LLC/0884-EX-CN-2018)

New 891.50000000-894.00000000 MHz FX 3847.000000 W 3847.000000 W M 1.20000000
% 2M50FXD OFDM

New 846.50000000-849.00000000 MHz FX 3847.000000 W 3847.000000 W M 1.20000000
% 2M50FXD OFDM

------
AndrewDucker
I can see a satellite transmitting powerfully to reach a phone on the ground.

But how are they going to pick up the transmission from a phone, which is
incredibly low power and designed to be picked up from a maximum range of
70km.

The Wikipedia article also says that timing considerations give a maximum
range of 35km. Which is a lot lower than the 2,000km of Low Earth Orbit.

~~~
ellisv
> I can see a satellite transmitting powerfully to reach a phone on the
> ground.

Yes, wouldn’t this just be like GPS?

I’m also not convinced the phone->satellite is practical/feasible.

------
ficklepickle
I'm trying to reconcile the fact this sounds like BS with the fact they just
raised 110m from Vodaphone et al.

In this vodaphone press release[0] they say it's not just an investment but
also a strategic partnership.

The founder is Abel Avellan. He previously ran Emerging Markets
Communications, Inc. I can't tell if they are still in operation, but it looks
like they have folded.

I found some old paid press releases[1] claiming they were going to
revolutionize cloud computing in Africa with SpeedNet, boasting zero latency
with 100mb/s transfer speeds over existing satellite links. Best I can tell,
it was just a thin client. It is "zero" latency 100mb/s because it all runs on
the same servers. Very deceptive.

There is a whole slew of related companies. They all seem to make use of paid
press releases and similar promotional stunts.

They tend to be located in cheap rental offices in Florida, at addresses also
used by hundreds of other corps.

I'm on my phone so I didn't go deep, but there is a clear pattern. Exaggerated
announcements of technology breakthroughs, which never materializes.

I guess they upped their game and managed to put on a good enough show to get
a sizeable investment.

I imagine it's an easier technical problem when the weak transmitter is in
space, probably with a directional antenna, with no nearby sources of
interference. All very much unlike a real environment.

[0] [https://investors.vodafone.com/news-releases/news-release-
de...](https://investors.vodafone.com/news-releases/news-release-
details/vodafone-rakuten-lead-investors-spacemobile)

[1]
[https://www.businesswire.com/news/home/20120524005227/en/Eme...](https://www.businesswire.com/news/home/20120524005227/en/Emerging-
Markets-Communications’-SpeedNet-Named-“Most-Transformative)

------
jpm_sd
Battery life on those phones is going to be /terrible/. Max TX power all the
time?

------
tantalor
> no escaping a mobile signal

That's a bizarre phrasing. Is it meant to be ironic?

Signal is something you want to have, not escape from.

~~~
vinniejames
Some folks like to switch off with plausible deniability

~~~
Nextgrid
Dead batteries seem like a plausible excuse.

------
est31
Are there any european companies riding the current wave of trying to build
satellite internet? Or is it US only?

~~~
steve19
I think China is also looking at building a starlink-type network, although I
don't have a link on hand.

OneWeb are partnered with Airbus although post-brexit they are no longer
headquartered within EU (London and other cities around the world).

SES, an EU firm, is developing a medium earth orbit satellite network and
would be well positioned to develop a LEO network.

------
neonate
[https://archive.md/M0b2L](https://archive.md/M0b2L)

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kalium_xyz
A new firm lies

