SOURCES
Where this data comes from
Distance from the Sun, speed, and one-way light time all come from NASA JPL's Horizons System — the same ephemeris service that powers most professional solar-system navigation software. No authentication required. Each probe needs two separate requests, since Horizons only accepts one observing center per call: Sun-centered for distance and speed, Earth-centered for distance and light time.
ssd.jpl.nasa.gov/api/horizons.apiSignal/contact status comes from NASA's official Deep Space Network feed — the same XML data that drives the eyes.nasa.gov DSN visualization. A probe frequently shows "not in contact"; that's real dish-scheduling behavior, not an error state.
eyes.nasa.gov/dsn/data/dsn.xmlLaunch date, heliopause crossing date, and constellation heading are real facts, but baked into the app rather than fetched live — they don't change often enough to need a live source.
Instrument health, shown on each probe's detail page, is illustrative wireframe data, not real telemetry — there's no public API that decodes actual Voyager instrument status.
Live figures are cached locally and refresh at most once every 15 minutes. If a refresh fails, the last known good values are shown rather than breaking the page.