A payload adapter is the structural interface that connects a satellite to the launch vehicle's upper stage. It must securely hold the payload during the extreme vibration and acceleration of launch, then cleanly release it at the precise moment of deployment. Standard adapters use clamp bands, separation bolts, or low-shock separation systems to achieve reliable deployment.
For rideshare missions carrying multiple payloads, dispensers like ESPA (EELV Secondary Payload Adapter) rings allow several small satellites to be stacked around a central primary payload. Companies like D-Orbit and Momentus have built satellite deployer platforms that act as orbital transfer vehicles, accepting payloads from a single adapter and releasing each satellite into its specific target orbit.