APRS/MIR PACKET TEST 11 March 1998 Bob Bruninga, WB4APR On 11 March 1998 a special MIREX/APRS test was conducted via the packet system on the Space Station MIR. The test was to show possible methods for improving the visibility of MIREX communications to students and schools. The objectives were to: APRS/MIR TEST: Since the Mir packet system has been operating well the last few weeks, Dr. Larsen [ N6CO] of the MIREX group suggested the APRS Mir test be conducted as soon as possilbe since precession was taking Mir passes earlier every day and it would soon be out of view during school hours. He authorized the APRS/MIR test on only two orbits on the 10th of March. Unfortunately the MIR packet system went off the air on these two orbits, so the test was extended to the next few orbits over the USA. The test was limited to the USA only because it had the largest numbers of existing APRS ground stations ready to test in sufficient numbers to fully load the system. But the delay further complicated matters since the next orbits over the USA were between 0230 AM and 0400 AM local time. As a result, the test was extended for a full 5 orbits to allow testers to choose a pass and still get some sleep. Although these 5 pass's of MIR covered 70% of the world Hams To make Mir appear to move on all groundstation maps, three special tracking-uplink stations beaconed the moving position of MIR via the MIR digipeater. One from California using the callsign MIR-6, one from Michigan using MIR-8, and one in Maryland using MIR-3 to match their callsign areas. West coast stations typically saw the moving MIR-6, midwest stations typically saw the incoming MIR-6 change to a MIR-8 and then east coast stations saw the moving ICON on their maps change to a MIR-3. To inject the downlink from Mir into the Internet, a few of the normal APRS I-Gates tuned their radios from the normal APRS frequency to the Mir downlink frequency. These Mir packets were intermingled with the normal stream of APRS packets into the APRServe Internet system. ALthough they would be seen on the main www.aprs.net maps they would be hard to distinguish from the usual 1000 to 1200 or more APRS stations on the air. To provide a unique display of the APRS/Mir packets alone, a special WEB page was designated to filter out only the APRS/MIR packets and display them spearately to users. During the day of the event there were over 11,000 hits on the server system representing a peak load of 150 simultaneous users and as many as 1000 users. CONCLUSIONS: THe test was completely successful in meeting all of the original objectives. THe short notice and early morning hours helped to reduce the number of participants to a nominal 100 stations. We think this number is representative of the nominal number of schools that could be authorized to simultaneously participate in future such Mir experiments. The test demonstrated the value of using a UI frame one-to-all packet protocol to improve the delivery of information to all ground stations. Further, the test demonstrated the value of a few special MIREX ground stations to uplink the moving Mir position reports and to relay real-time MIREX bulletins and announcements that can be received by all stations in the footprint including receive-only school stations. Finally, the test showed the value of multiply internet connected ground stations for not only providing a continuum of data from the downlink across the whole country, but also for providing WEB access to students and schools outside of the footprint or without amateur radio equipment. All of the APRS stations want to thank the MIREX team and also those normal Mir BBS users who were inconvenienced by this test, for this opportunity to conduct this important experiment.