Android 15 Developer Preview 2 rolling out to Pixel
Android 15 adds UI elements to ensure a consistent user experience across the satellite connectivity landscape." A system-level Auto-connected to satellite" notification conveys how You can send and receive messages without a mobile or Wi-Fi network" with a shortcut to Open Messages" or get more information. Meanwhile, note the status bar icon at the right.
Speaking of Google Messages, Android 15 provides support for SMS/ MMS applications as well as preloaded RCS applications to use satellite connectivity for sending and receiving messages." Other apps will also be able to detect when a device is connected to a satellite, giving them more awareness of why full network services may be unavailable."
Abner Li at 9To5Google
9To5Google also has a list of all the new features in this Developer Preview with copious amounts of screenshots.