 Toby asks, how do Blockstream's Bitcoin satellites work, and what are their potential use cases? Blockstream runs five satellites orbiting the earth and sending blockchain data to almost any spot on our planet's surface. Can you explain how this works in detail? Are the satellites real full nodes, or do they just relay data from Earth? If they are full nodes, how do they update them? What is needed to feed my full nodes with their satellite data? What data are they broadcasting? Is it only the most recent, or could I do an initial block download with it? Finally, where do you think will they be adopted in the future, and what potential has the API they want to make available next January? Sorry for the amount of questions, but I hope you can elaborate a bit on this really interesting topic. This topic is fascinating, but I think there is a lot of misunderstanding and misinformation. Part of that is the term Bitcoin satellites, or Blockstream's Bitcoin satellites. What you imagine here is a super-secret project by a hidden, trillionaire, mega-evil person with lots of minions, who built rockets in order to launch into space special satellites on the outside, say Blockstream. Within those satellites, there are little jars of cloned matter from the DNA retrieved from Satoshi Nakamoto during the early stages of Bitcoin. Using this cloned data, Blockstream grows miniature Satoshi Nakamoto in space, who rewrite the software in orbit in order to ensure its validity. That is not what is happening. Also, they are not Bitcoin satellites. Also, Blockstream didn't launch satellites. Also, they are not full nodes. We kind of got on a wafer. Let's take this back down to Earth, because that is where all of it happens. The Blockstream satellite project is basically the leasing of broadcast bandwidth on specific frequencies from commercial communication satellites that lease frequencies to providers. Blockstream can use these lease frequencies to transmit a signal from ground stations that is repeated. This signal is an encoded signal that contains blocks and transactions broadcast from the ground, that are then bounced off satellites and transmitted to Earth. In order to use this, what you need to use is a relatively easy to find commercial TV satellite dish, in the areas where they have coverage, a regular dish. I have seen people use their direct TV satellite TV dish and repurposing it. You will need to change the transceiver at the end of the dish. That is the little piece of electronics that is sitting in the focal point of the parabolic dish, that actually receives the signal from the satellite. Those are relatively inexpensive. You connect that via a coaxial cable to a special device that is basically a software radio. It is a software-based broadband radio receiver that can take the entire coaxial signal and frequencies fed in. Using software can extract from that the encoded data that Blockstream is transmitting from ground stations. Specifically, what this is, is leasing on commercial satellites. There are no full nodes in space. That is not what has happened. Somebody actually suggested doing that, a project led by Jeff Garzik, one of the earlier core developers. That project failed, unfortunately. It would have been interesting, but that is not what is happening here. If you want to do this, you can buy the equipment for about $150. You can buy the software-defined radio, the transceiver, repurposed satellite dish, or buy a cheap one, or a second-hand one. You can do that. It is a lot easier to do in a stationary environment, where you can carefully calibrate and point the dish in the right direction. I have seen people try to do it on vans and mobile units, but unless you spend $2,000 or $3,000 for a server-motorized satellite tracking system that follows the satellite as you move, you will have to spend 20 or 30 minutes recalibrating and pointing the antenna in the right direction. It is not easy. If you have ever done satellite TV, you know what that is all about. What is this useful for? It is useful for receiving bitcoin information and keeping a node synced, and validating transactions in an environment where you are under heavy governmental censorship, or where there is a significant risk to anyone being able to see that that is the kind of traffic you are exchanging with the rest of the world. Imagine an environment where you are in a war zone, in a refugee center, in an area that is under civil war, or something like that. Disguising a satellite dish is fairly easy. You can put it in such a location that it is not visible from anywhere, not even from the sky. You can camouflage the fact that it is a dish, and you can receive this information. That makes it a very powerful tool, because it increases censorship resistance. At the same time, transmitting the signal out to the satellite can be done from any number of commercial ground stations, or possibly setting up a giant private dish to point towards the satellite, to do the uplink from other locations. These can be leased in different countries, so you have quite a bit of resilience there. You can do an initial block download with it. You can only get updated blocks and transactions, but it is still extremely useful. If you want to ensure that what you are receiving is real, other than the proof of work, obviously, can't be forged, but if you want to cross-check it against something else, then you would have to set up an alternative mechanism and compare the two. What you could do, for example, is download a much smaller amount of data off a modem, or VPN, or using some other communication medium, in order to cross-check with another node, the blocks you are receiving. For example, you could download just block headers off a modem, and then download the full blocks with all of the transactions off the satellites. That can be very useful in an environment where you have very limited bandwidth. I really, really wish that this was a series of giants, geostationary orbits, blockstream satellites that inside had rows of jars with clone DNA tissue of Satoshi Nakamoto, and many baby Satoshis that have been raised by robots to recode the Bitcoin Core software in space with their tiny little cute keyboards, while being fed from algae grown under UV light, but that is not exactly how it works.