Ask HN: Which protocols and data formats are used for space communication? | Hacker News Reader

Ask HN: Which protocols and data formats are used for space communication?

16 pointsjviotti7 comments

For engineers working at i.e. SpaceX, NASA, the European Space Agency, etc where can I learn more about the protocols, serialization formats and related technologies using for ground-space data interchange?

i.e. are the using technologies like ASN.1 over tuned versions of TCP for high-latency use cases?

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The protocols used for space communications are a mix of standards and proprietary. For example, the SpaceX Falcon 9 uses an Ethernet-based protocol called XDR (evolved from NASA's TDM) to communicate with ground stations during launch operations; this is also known as "ground station control" or GSC mode in industry parlance. This allows engineers at both ends - on Earth & onboard spacecraft --to monitor telemetry data being transmitted by sensors aboard their respective craft via standard IP packets over TCP/IP using UDP datagrams when necessary.

Daniel Estévez (https://destevez.net/) has lots of interesting blog posts on using tools like GNU Radio and Jupiter to decode transmissions from various objects in space. He's recently also been looking at LTE.

I would also recommend CuriousMarc who has done a lot of work with his friends on restoring some radio equipment from the Apollo missions: https://www.youtube.com/watch?v=v49ucdZcx9s&list=PL-_93BVApb... There are lots of good explanations of the how and why in those videos.

Traditionally, space agencies have used CCSDS (Consultative Committee for Space Data Systems) protocols for applications such as interoperability with ISS and Mars rovers and orbiters. Newer organizations use more contemporary protocols used by large communities for terrestrial applications to avoid engineering new solutions just for space.

https://public.ccsds.org/default.aspx

I had a friend who worked at Planet labs for a while - he had the craziest stories as to how laser based communication systems worked. He even had a co-worker who as a physicist had thought through how communicating with lasers between large interstellar distances could work. Very curious to see what this thread returns :)

In general, distant space based communication will use some sort of forward error correction because TCP-style interactive correction would cause huge delays. TCP is just not a protocol designed for latencies on the order of minutes. I could totally see them using UDP though either on top of or below the error correction.

Here is a good start: https://public.ccsds.org/default.aspx

im curious of anyone uses json in space

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