Jacob Johnson
Senior Software Engineer at Ethermed
Jacob is an Elixir developer based in Minneapolis with 8+ years building on the BEAM — from healthcare data platforms to astronomical computation engines. Currently a senior engineer at Ethermed, he is building Turning Sky Labs: a pure-Elixir engine that computes planetary positions from NASA/JPL ephemeris data and serves them as an MCP server for AI agents. He likes hard problems that make the BEAM do things it wasn’t designed for.
Talk:
Calculating the Sky in Pure Elixir
NASA’s Jet Propulsion Laboratory publishes the same ephemeris data used to navigate interplanetary missions - planetary positions for the entire solar system. I built an engine that computes these positions in real-time, from the original JPL data, in pure Elixir. No C bindings, no NIFs, no ports. Pattern matching, ETS, and OTP all the way down.
This talk starts with a live demo: a 3D celestial sphere in the browser (https://ex-ephemeris.fly.dev), computing real astronomy on a $7/month fly.io machine with BEAM VM telemetry visible alongside the planets. From there, I’ll explore the architecture decisions that made it possible - why GenServer-per-observer, why ETS as a scientific data store, why a pipeline with telemetry at every stage - and where it’s going: as an MCP server providing real-world astronomical data to AI agents.
The BEAM wasn’t designed for scientific computing. I’ll show you why it should have been - and what becomes possible when you can compute the state of the sky for any observer, at any moment, and start correlating it with everything else.
Key takeaways:
- Why the BEAM is a legitimate platform for scientific computing - demonstrated with a working engine and benchmarked against established tools like Swiss Ephemeris and Python’s Skyfield for both accuracy and performance
- Architecture patterns for real-time scientific streaming: GenServer-per-observer, ETS as a hot-path data store, pipeline composition with telemetry at every stage boundary
- How to handle computationally intensive workloads on a single fly.io machine — 10 Hz streaming, backpressure via mailbox depth, and what the BEAM gives you for free (supervision, fault tolerance, graceful degradation) that C and Python libraries don’t
- Where domain-specific Elixir engines are going - a look at serving real-world computation through MCP for the emerging agent ecosystem
Target audience:
- Intermediate to advanced Elixir developers curious about pushing the BEAM beyond web applications. Developers who’ve wondered whether Elixir can handle computationally intensive, real-time workloads. Anyone interested in what OTP patterns look like when applied to scientific computing instead of web requests. No astronomy background needed - the patterns are universal, the domain is just uncommonly interesting.