Tech startup connects to two satellites in orbit from Earth via Bluetooth
techradar.com
techradar.com
It's one thing to use 2.4GHz spectrum in orbit between two satellites where there probably isn't much interference. That's interesting/cool. It's another thing to imply a BT consumer device on earth can connect to a satellite which seems like grossly misleading claim.
"Hubble’s approach directly tackles these problems by enabling standard Bluetooth devices to connect to their satellite network without cellular reception simply with a software update" towards the middle of the article.
Maybe the actual tech they’re shooting for is to wrap the BT protocol or modulate it up to blast at satellites? Then you could enable connectivity for existing BT sensor networks and such. They explicitly say that it doesn’t require a hardware retrofit, only firmware, though. I suppose you could hit some sort of harmonic on a 2.4GHz antenna, but that would be very dependent on the frontend and antenna design, and the SNR would probably suck. Something doesn’t add up.
Conceptually, I’m also not really sure if the pitch makes sense. Sure, let’s say you can do firmware patches to BT chipsets, but was that the expensive/hard part? Does the BT protocol and spec make sense in the context of hitting a satellite? It’s clearly not designed for it in terms of latencies, airtime, etc.
I guess they get 21dB from directional antenna, another 21dB from message coding (essentially repeating each bit 128 times to improve SNR)?
2.4 GHz is attenuated by water vapour, which there is less of at higher altitude and none in space. So I'd think the loss to atmospheric absorption looking up to a satellite would be much, much less than it is at sea level.
Using a calculator [1] that takes gain into account, looks like a narrow beam antenna at 35 dBi could bring it down to a comfortable -75dBm - and I imagine you could have even higher gain with phased array antennas. The real problem is aiming the beams, and SpaceX has already proven this is possible.
figures 2-2-8 and 2-2-9 graph attenuation due to oxygen and water vapor expected for frequencies 1-30GHz, on a vertical total atmospheric path (sea to vacuum)
page down for water droplet and rain losses per kilometer at various droplet sizes
Whereas Bluetooth speakers for example will all (of the ones I’ve come across) auto-accept the pin without user input, typically because (I guess) the limited amount of buttons and displays make user input difficult. And even if it was like use volume plus and volume minus and play button, and use it to step digit by digit while the speaker reads aloud, it would be super finicky. So instead typically the Bluetooth speakers are made so that you have to press and hold some button on startup for example or press a dedicated other button, in order to enter pairing mode and so random people will not be able to connect to your speakers from outside your house unless they happen to try to do it at the very same time as the short window of time where you’ve turned on pairing. And because of that those speakers don’t really need the PIN for protection.
However, even a lot of phones and computers will only allow pairing when you set the device “visible” I think, and that is often I think default to only stay on for some number of minutes in many cases. But I’m not sure if PIN is typically used in this situation or not also.
There are other modes depending on hardware availability. If the device only has a screen there's a mode where it displays a pin for you to enter on the host. If it only has input but no screen, the host can give you a pin to enter on the device.
The pin can be hardcoded (as with '0000') or generated on the fly. You can also have a pin-less device respond to pairing requests with a hardcoded pin, or obtain the pin through some side channel like a separate radio or a wired connection.
In all cases, the devices typically use diffe-hillman to negotiate a secure link after pairing. You do have the option to disable encryption.
Additionally, "pairable" and "visible" are totally independent concepts. A device can be "invisible" but still accept pairing from a device that knows its address. You can also be visible without accepting pair requests.
This part of the BT spec was actually thought out quite extensively. There seems to be a provision for every corner case I've been able to imagine. No matter your situation, there's always a mode you can use to get your connection up.
I'm always fascinated by the lack of incredulity of journalists to just parrot the most outlandish nonsense imaginable without question:
> With nearly five billion Bluetooth devices sold annually, the impact of this breakthrough could be huge.
Can you imagine? 5 billion devices all pairing with satellites? What a breakthrough!
What a joke
Beyond a single low bandwidth point to point connection, the pain increases exponentially as the signal quality degrades geometrically. It really is not meant for wide scale networks. Not in any way.
There is no application for "Bluetooth to orbit" that can't be served with other technology at lower cost and vastly improved performance. Bluetooth is just objectively the wrong technology for this.
> they’ve successfully reached their orbits and managed to receive signals [from Earth] from a simple 3.5mm Bluetooth chip over an astonishing distance of 600 km.
Does this mean you could eavesdrop all Bluetooth connections from a single satellite?
Beyond that case, you'd have to have a secret backdoor into the encryption algorithm, and we don't think there is such a backdoor (AFAIK).
You could of course sniff on all the unencrypted BLE beacons out there, but I seriously doubt that data is interesting enough to be worth a spy satellite network.
Far, far more concerning is the ability for a satellite to effectively jam Bluetooth across the continent. Bluetooth does not handle congestion well, and signal quality degrades very quickly with interference. Imagine your headphones cutting out when this satellite is overhead.
“Do you see a ‘forget satellite’ button?”
Also funny: "using off the shelf chip and a software update" is also a joke. Those IC's are software defined radios... Qualcom, Broadcom, spectrum regulatory authorities, whoever, won't let you do it. ( But the latter might send you to prison for trying to break the laws of men & physics )
Overall I don't think it's impossible: Someone stated it would be unidirectional, and the bitrate was not given (read: could even be minutes per bit for all we know).
But yeah, I'm sceptical, too. A gateway would have made more sense to me, because it does not require firmware-level cooperation with chip set manufacturers and you can reuse existing space networks. Especially since they're not aiming to add the feature into future ICs (which could have driven sales across the whole industry), but backport it instead, competing with the manufacturers and voiding existing FCC et al. certification.
It is very bold to claim that a phone can beam Bluetooth up to satellite with just a firmware update.
You can do firmware updates on bluetooth chipsets, say for example Silicon Labs EFR32, to have a custom 2.4 ghz protocol. Wirepas is an example of a proprietary protocol that runs on 802.15.4 SoCs.
Also, ofcourse you can change the software of a software defined radio. Why do we even have to mention this here ?
You've interpreted their hand wavey marketing statement far too literally. Of course a plain vanilla bluetooth hardware + software stack won't be able to communicate with a satellite. They are saying that you can run their protocol on standard bluetooth chipsets for people who are designing NEW products. Loading a custom protocol onto an already certified product would nullify its certification. Why do we have to mention this here ?
We'll see.
this article is apparently about a proof of concept to follow up with claims they have made previously for their funding round - where they had simply planned to launch a satellite to show this off. so now they've shown it off.
but if you were curious about any revolution or technical details, there are not any in any of their blog posts or this article.
its interesting but probably does more harm than good for them. the technical limitations aren't present, they probably have no moat for what they can do, or its all entirely bullshit.