The big win here is having a GC by default, with the ability to reduce heap allocations (via stack) just by adding in more typing annotations.
Switching to OxCaml with exclave_ stack_ annotations drops
p99.9 latency from 29 ns to 9 ns per packet on the dispatch
hot path, and removes GC pressure entirely (394 minor GCs to
zero over 25 million packets). Throughput is comparable [...]
I got a similar result with my 'httpz' stack a few months ago (https://anil.recoil.org/notes/oxcaml-httpz) which my website's been running on without drama. And, I gotta say, OxCaml's a surprisingly robust compiler for being packed full of bleeding edge extensions: not a single crash on my infra is attributable to a compiler bug (plenty of bad OCaml code, but not due to a compilation bug)
Yeah; all the really dangerous extensions are gated behind flags. But there's still a very significant number of optimisations available by default that just work well. I've taken to compiling my normal OCaml code with OxCaml these days to get a free speed boost (but buyer beware: the dependency management can be tricky; I have a giant monorepo to help out https://github.com/avsm/oxmono)
Nim does much the same. It prefers the stack, wraps dynamic heap types in value-semantic unique pointers by default, and avoids implicit copies wherever it can. I could see compiled languages trending in the stack-managed direction long term.
CCSDS guides you to reinvent everything from scratch, I doubt memory safety is the biggest attack surface when you implement this stack. I dont know how big players implement networking for their satellites, but personally I would choose to fit something existing and battle-tested like TLS instead of reinventing data encryption, just look at those documents: https://www.google.com/search?client=firefox-b-lm&q=ccsds+en...
The TL;DR here (https://ccsds.org/Pubs/350x9g2.pdf) seems to be "AES GCM", but with lots of lots of legacy protocols due to older birds in the sky. DTLS or HTTP3 would seem to be a better choice these days...
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