There are plenty of Artemis II trackers out there. I looked at a bunch and kept running into the same issues - some had data that didn't look right, it was hard to use on smaller screen, others felt overly complicated for what I actually wanted to know: what's the crew doing, where is Orion, how fast is it going. The best one I found was issinfo.net/artemis, which inspired a lot of the design.

So I built my own. The part that was genuinely interesting to me was the data. Turns out anyone can query JPL's Horizons API for full ephemeris data on the Orion spacecraft - position, velocity, range - for free. I had no idea this existed.

Even better: NASA's Deep Space Network publishes a live XML feed (eyes.nasa.gov/dsn/data/dsn.xml) that updates every 5 seconds showing exactly which ground antennas are talking to which spacecraft. Right now two dishes in Canberra are locked onto Orion - one sending commands, both receiving 6 Mbps of S-band telemetry at 296,000 km. You can see Juno at Jupiter, JWST, Mars Odyssey, all in the same feed. It's pretty amazing what's just sitting there in the open.

The app fetches trajectory from Horizons, crew activities from NASA's published flight plan, and live ground station status from DSN. I'll be honest - it's mostly vibe-coded with supervision. The data pipeline is the part that was more manual: figuring out what's publicly available, how to compute relative positions from raw vectors, how to cache and backfill. That was the fun part.

Code is open on GitHub. I built it for myself and as a fun exercise, but happy for any feedback - especially around data correctness and what other public data sources are out there that I might be missing.

Source: https://github.com/dmarchuk/artemis.fyi