What is the purpose of digital store-and-forward functions on an amateur radio satellite?
Why A low Earth orbit satellite is only in view of any given ground station for about 10 to 15 minutes per pass, so two distant stations are rarely in view at the same time. A store-and-forward digital satellite acts like a flying mailbox: it accepts uploaded messages into onboard memory, carries them around the orbit, and lets stations download them on a later pass when the satellite comes over the horizon. This is packet-style messaging rather than a real-time transponder relay.
Watch out The choice about relaying messages between satellites describes crosslinking, which is a different technique; store-and-forward moves mail between ground stations using the satellite's memory, not between spacecraft.
Store-and-forward = orbiting mailbox: upload now, someone downloads on a later pass.