FAQ: Blockstream Satellite

We’re pleased to have launched Blockstream Satellite today!

What did we announce?

We announced the launch of Blockstream Satellite, a new service that broadcasts real-time Bitcoin blockchain data from satellites in space to almost everyone on the planet.

Almost everyone?

Our plans cover 99.999996% of the world’s population, which does not include the few thousand people living in Antarctica. But if there’s a compelling use case for Blockstream Satellite in Antarctica, we’re open to covering it. Just let us know!

What is Blockstream Satellite for?

Blockstream Satellite helps make bitcoin available to even more people in the world, especially where internet access is either unavailable or expensive. The more people using bitcoin, the more use cases there are for bitcoin. This growth in usage strengthens the overall robustness of the network.

What else does Blockstream Satellite provide?

Blockstream Satellite also provides the following:

What’s the current bandwidth achieved on Blockstream Satellite so far?

The system is currently designed to guarantee 64kbit/sec. This provides adequate bandwidth to reliably maintain synchronization with the network with modest delay. Further upgrades to the radio system may achieve higher bandwidth.

What’s the latency for receiving the Blockstream Satellite broadcast?

The speed of light means that the transmission to geosynchronous orbit and back takes at least 280 milliseconds. In addition to the communications latency additional delays are caused by signal processing and needing to simply wait for the message to be transmitted. A whole block takes several minutes to transfer. Bitcoin is inherently delay tolerant and for most applications delays are basically irrelevant. Bitcoin mining is more delay sensitive and access to lower delay signals optimized for mining is one of the future services we plan to charge for.

Does this system allow for two-way communication?

Currently the system is only one-way. It provides a way to receive new blocks and ensure nodes stay in sync. However, transactions can be sent using other communication channels such as SMS or conventional satellite internet services. As transaction data is very small, even using the most expensive satellite internet service, it would cost less than $0.01 per transaction.

Are you charging fees for Blockstream Satellite?

With Blockstream Satellite, Blockstream is providing end users the blockchain data for free. We have plans to extend the network over time to be an open platform for application developers to build on. We will also charge for various future add-ons such as lower latency services. When we make available advanced features, capabilities, and services intended for business use, we plan on monetizing those.

Are these purpose-built or existing satellites within the Blockstream Satellite network?

We are leasing bandwidth on existing, commercial, geosynchronous satellites orbiting at over 22,000 miles above the Earth. There are many satellites already in space, so why not use them? So far we have active operations on these satellites: Galaxy 18 (covering North America), Eutelsat 113 (covering South America), and two transponders on the Telstar 11N satellite (one covering Africa and one covering Europe). We’ll be bringing on additional satellites soon to provide even more coverage.

Are the satellites running full Bitcoin nodes?

No, the satellites themselves don’t run nodes. The ground stations run the full nodes and then uplink the blockchain data to the satellites, which then broadcast the data to large areas of the planet. The satellites are acting as repeaters.

What will the interface be for people using Blockstream Satellite?

The user interface is the real magic of the system. Ordinarily, end user satellite equipment is very expensive (thousands of dollars). Blockstream Satellite is uniquely designed to dramatically reduce this cost. Using open source technologies, anyone can receive the signal with a small satellite dish (similar to a consumer satellite TV dish) and a USB SDR (software defined radio) interface. The total equipment cost for a user is only about $100. The software is free. The software interface is the open source GNU Radio software, which is the receiver. GNU Radio will send data to the FIBRE protocol, which is the bitcoin process and is where the blocks reside.

Using our website documentation, users can see the list of what they need to get started, including a list of equipment, how to point their antenna, and how to use the software.

Is this related to Jeff Garzik’s former BitSat idea?

No. We are long-time members of the Bitcoin community and of course heard of Jeff’s prior project to launch new satellites into space in order to broadcast the Bitcoin blockchain. Our idea and implementation is novel in several ways. There are many satellites already in space, so it is more effective to use them. We did the analysis and selected the approach of leasing capacity on existing, commercial, geosynchronous satellites already orbiting at over 22,000 miles above the Earth versus building and launching new satellites into space. Also, Blockstream Satellite makes extensive use of open source software, namely GNU Radio and FIBRE, which has allowed us to greatly reduce costs – both in order to run the network and for network users themselves – over conventional satellite projects.

Anything else to tell me about what Blockstream Satellite is or is not?

With the information above, you probably have a good understanding of what Blockstream Satellite is. Here are a few explanations of what Blockstream satellite is not:

What if after all of the above information, I am ready to get started?

Go for it! Visit the getting started page and make it happen. Power users may even want to make it more fun by sharing their most unique or challenging configurations. Could this be your next tweet?

I got Blockstream Satellite working on the side of the road with a petrol generator, a local wifi hotspot, and satellite wifi uplink to relay transactions! #bitcoinftw


What if after all of the above information, I still think this is terrible?

This helps the broad bitcoin ecosystem, for which we don’t apologize. It’d be nice if we all competed on that goal! We believe in choice, including the choice to offer services like these to make the world a better place.