About SpaceAPRS

The International Space Station carries an amateur radio packet digipeater, currently on 437.825 MHz (ARISS moves it between radios; their status page says which is on). A station on the ground sends an APRS packet with the path ARISS; if the station is above the horizon and hears it, it repeats the packet back down, where any station under the footprint can hear it. IGates that hear the downlink put it on the internet, and that is where this site listens. Those IGates are run by volunteers, amateur radio operators who keep a receiver and an internet connection going at their own expense so that packets like these reach anyone at all. Where they are is where the station can be heard from; a pass over open ocean, or over country with no IGate, leaves no trace here however many stations got through.

What counts as heard

A packet appears here only when the space station actually repeated it. That means its path carries one of the station's callsigns as a used hop, such as RS0ISS*. Asking for ARISS is not enough: most packets sent at a satellite are never heard by it, and they still carry the alias in their path. The station's own status beacons are logged separately.

Where the station is

The orbit is computed in your browser from the current two-line element set, fetched from CelesTrak twice a day. The footprint is the circle on the ground from which the station is above the horizon, about 2,200 km across. The ground track is the next orbit.

Quiet periods

The packet system is switched off during crew events and school contacts.

Sources

Packets come from the APRS-IS network. The orbit comes from CelesTrak. The map is © OpenStreetMap contributors, drawn with Protomaps.

Who

SpaceAPRS is built and run by APRS Connect, an APRS app that works the ISS from a phone and a handheld. The site is not an official ARISS service; ARISS itself is at ariss.org.