AO-13 was the most complex amateur satellite to date. The satellite's computer follows a calendar in switching among transponders modes. Telemetry beacons transmit data via packet, cw and rtty. The hamsat delivered essential communications in 1992 after Hurricane Iniki leveled parts of Hawaii. After normal public circuits broke down, AO-13 and other hamsats moved health and welfare messages from devastated areas to anxious relatives and friends.
Solar power makes sunlight important.
Even a partial eclipse of the Sun by the Moon can affect a satellite. During a 1992 eclipse, sunlight reaching AO-13 was cut 40 percent. Twilight was reported in the satellite's housekeeping telemetry as a drop in solar panel temperature. The low illumination necessitated turning off a transponder for a time to allow full recharging of the satellite's battery. Amateur radio satellites are experimental, of course, so glitches do turn up.